Commit Graph

1974 Commits

Author SHA1 Message Date
Nicholas Piggin
4bf2c9605d KVM: PPC: Book3S HV: Tolerate treclaim. in fake-suspend mode changing registers
commit 267cdfa21385d78c794768233678756e32b39ead upstream.

POWER9 DD2.2 and 2.3 hardware implements a "fake-suspend" mode where
certain TM instructions executed in HV=0 mode cause softpatch interrupts
so the hypervisor can emulate them and prevent problematic processor
conditions. In this fake-suspend mode, the treclaim. instruction does
not modify registers.

Unfortunately the rfscv instruction executed by the guest do not
generate softpatch interrupts, which can cause the hypervisor to lose
track of the fake-suspend mode, and it can execute this treclaim. while
not in fake-suspend mode. This modifies GPRs and crashes the hypervisor.

It's not trivial to disable scv in the guest with HFSCR now, because
they assume a POWER9 has scv available. So this fix saves and restores
checkpointed registers across the treclaim.

Fixes: 7854f7545b ("KVM: PPC: Book3S: Rework TM save/restore code and make it C-callable")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210908101718.118522-2-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22 12:26:42 +02:00
Alexey Kardashevskiy
ec5cab3798 KVM: PPC: Fix clearing never mapped TCEs in realmode
[ Upstream commit 1d78dfde33a02da1d816279c2e3452978b7abd39 ]

Since commit e1a1ef84cd ("KVM: PPC: Book3S: Allocate guest TCEs on
demand too"), pages for TCE tables for KVM guests are allocated only
when needed. This allows skipping any update when clearing TCEs. This
works mostly fine as TCE updates are handled when the MMU is enabled.
The realmode handlers fail with H_TOO_HARD when pages are not yet
allocated, except when clearing a TCE in which case KVM prints a warning
and proceeds to dereference a NULL pointer, which crashes the host OS.

This has not been caught so far as the change in commit e1a1ef84cd is
reasonably new, and POWER9 runs mostly radix which does not use realmode
handlers. With hash, the default TCE table is memset() by QEMU when the
machine is reset which triggers page faults and the KVM TCE device's
kvm_spapr_tce_fault() handles those with MMU on. And the huge DMA
windows are not cleared by VMs which instead successfully create a DMA
window big enough to map the VM memory 1:1 and then VMs just map
everything without clearing.

This started crashing now as commit 381ceda88c4c ("powerpc/pseries/iommu:
Make use of DDW for indirect mapping") added a mode when a dymanic DMA
window not big enough to map the VM memory 1:1 but it is used anyway,
and the VM now is the first (i.e. not QEMU) to clear a just created
table. Note that upstream QEMU needs to be modified to trigger the VM to
trigger the host OS crash.

This replaces WARN_ON_ONCE_RM() with a check and return, and adds
another warning if TCE is not being cleared.

Fixes: e1a1ef84cd ("KVM: PPC: Book3S: Allocate guest TCEs on demand too")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210827040706.517652-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22 12:26:25 +02:00
Nicholas Piggin
ba5d4dc003 KVM: PPC: Book3S HV Nested: Reflect guest PMU in-use to L0 when guest SPRs are live
[ Upstream commit 1782663897945a5cf28e564ba5eed730098e9aa4 ]

After the L1 saves its PMU SPRs but before loading the L2's PMU SPRs,
switch the pmcregs_in_use field in the L1 lppaca to the value advertised
by the L2 in its VPA. On the way out of the L2, set it back after saving
the L2 PMU registers (if they were in-use).

This transfers the PMU liveness indication between the L1 and L2 at the
points where the registers are not live.

This fixes the nested HV bug for which a workaround was added to the L0
HV by commit 63279eeb7f ("KVM: PPC: Book3S HV: Always save guest pmu
for guest capable of nesting"), which explains the problem in detail.
That workaround is no longer required for guests that include this bug
fix.

Fixes: 360cae3137 ("KVM: PPC: Book3S HV: Nested guest entry via hypercall")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Link: https://lore.kernel.org/r/20210811160134.904987-10-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22 12:26:25 +02:00
Nicholas Piggin
962ce043ef KVM: PPC: Book3S HV Nested: Sanitise H_ENTER_NESTED TM state
commit d9c57d3ed52a92536f5fa59dc5ccdd58b4875076 upstream.

The H_ENTER_NESTED hypercall is handled by the L0, and it is a request
by the L1 to switch the context of the vCPU over to that of its L2
guest, and return with an interrupt indication. The L1 is responsible
for switching some registers to guest context, and the L0 switches
others (including all the hypervisor privileged state).

If the L2 MSR has TM active, then the L1 is responsible for
recheckpointing the L2 TM state. Then the L1 exits to L0 via the
H_ENTER_NESTED hcall, and the L0 saves the TM state as part of the exit,
and then it recheckpoints the TM state as part of the nested entry and
finally HRFIDs into the L2 with TM active MSR. Not efficient, but about
the simplest approach for something that's horrendously complicated.

Problems arise if the L1 exits to the L0 with a TM state which does not
match the L2 TM state being requested. For example if the L1 is
transactional but the L2 MSR is non-transactional, or vice versa. The
L0's HRFID can take a TM Bad Thing interrupt and crash.

Fix this by disallowing H_ENTER_NESTED in TM[T] state entirely, and then
ensuring that if the L1 is suspended then the L2 must have TM active,
and if the L1 is not suspended then the L2 must not have TM active.

Fixes: 360cae3137 ("KVM: PPC: Book3S HV: Nested guest entry via hypercall")
Cc: stable@vger.kernel.org # v4.20+
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-28 13:30:59 +02:00
Nicholas Piggin
2b9ffddd70 KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow
commit f62f3c20647ebd5fb6ecb8f0b477b9281c44c10a upstream.

The kvmppc_rtas_hcall() sets the host rtas_args.rets pointer based on
the rtas_args.nargs that was provided by the guest. That guest nargs
value is not range checked, so the guest can cause the host rets pointer
to be pointed outside the args array. The individual rtas function
handlers check the nargs and nrets values to ensure they are correct,
but if they are not, the handlers store a -3 (0xfffffffd) failure
indication in rets[0] which corrupts host memory.

Fix this by testing up front whether the guest supplied nargs and nret
would exceed the array size, and fail the hcall directly without storing
a failure indication to rets[0].

Also expand on a comment about why we kill the guest and try not to
return errors directly if we have a valid rets[0] pointer.

Fixes: 8e591cb720 ("KVM: PPC: Book3S: Add infrastructure to implement kernel-side RTAS calls")
Cc: stable@vger.kernel.org # v3.10+
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-28 13:30:59 +02:00
Nicholas Piggin
f38527f189 KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
[ Upstream commit bc4188a2f56e821ea057aca6bf444e138d06c252 ]

vcpu_put is not called if the user copy fails. This can result in preempt
notifier corruption and crashes, among other issues.

Fixes: b3cebfe8c1 ("KVM: PPC: Move vcpu_load/vcpu_put down to each ioctl case in kvm_arch_vcpu_ioctl")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210716024310.164448-2-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28 13:30:56 +02:00
Nicholas Piggin
b85dadd434 KVM: PPC: Book3S: Fix CONFIG_TRANSACTIONAL_MEM=n crash
[ Upstream commit bd31ecf44b8e18ccb1e5f6b50f85de6922a60de3 ]

When running CPU_FTR_P9_TM_HV_ASSIST, HFSCR[TM] is set for the guest
even if the host has CONFIG_TRANSACTIONAL_MEM=n, which causes it to be
unprepared to handle guest exits while transactional.

Normal guests don't have a problem because the HTM capability will not
be advertised, but a rogue or buggy one could crash the host.

Fixes: 4bb3c7a020 ("KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210716024310.164448-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28 13:30:56 +02:00
Suraj Jitindar Singh
f3d2278a81 KVM: PPC: Book3S HV: Fix TLB management on SMT8 POWER9 and POWER10 processors
[ Upstream commit 77bbbc0cf84834ed130838f7ac1988567f4d0288 ]

The POWER9 vCPU TLB management code assumes all threads in a core share
a TLB, and that TLBIEL execued by one thread will invalidate TLBs for
all threads. This is not the case for SMT8 capable POWER9 and POWER10
(big core) processors, where the TLB is split between groups of threads.
This results in TLB multi-hits, random data corruption, etc.

Fix this by introducing cpu_first_tlb_thread_sibling etc., to determine
which siblings share TLBs, and use that in the guest TLB flushing code.

[npiggin@gmail.com: add changelog and comment]

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210602040441.3984352-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:53:14 +02:00
Nathan Chancellor
684bddacf1 KVM: PPC: Book3S HV: Workaround high stack usage with clang
commit 51696f39cbee5bb684e7959c0c98b5f54548aa34 upstream.

LLVM does not emit optimal byteswap assembly, which results in high
stack usage in kvmhv_enter_nested_guest() due to the inlining of
byteswap_pt_regs(). With LLVM 12.0.0:

arch/powerpc/kvm/book3s_hv_nested.c:289:6: error: stack frame size of
2512 bytes in function 'kvmhv_enter_nested_guest' [-Werror,-Wframe-larger-than=]
long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
     ^
1 error generated.

While this gets fixed in LLVM, mark byteswap_pt_regs() as
noinline_for_stack so that it does not get inlined and break the build
due to -Werror by default in arch/powerpc/. Not inlining saves
approximately 800 bytes with LLVM 12.0.0:

arch/powerpc/kvm/book3s_hv_nested.c:290:6: warning: stack frame size of
1728 bytes in function 'kvmhv_enter_nested_guest' [-Wframe-larger-than=]
long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
     ^
1 warning generated.

Cc: stable@vger.kernel.org # v4.20+
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/1292
Link: https://bugs.llvm.org/show_bug.cgi?id=49610
Link: https://lore.kernel.org/r/202104031853.vDT0Qjqj-lkp@intel.com/
Link: https://gist.github.com/ba710e3703bf45043a31e2806c843ffd
Link: https://lore.kernel.org/r/20210621182440.990242-1-nathan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14 16:53:05 +02:00
Nicholas Piggin
bf365066fb KVM: PPC: Book3S HV P9: Restore host CTRL SPR after guest exit
[ Upstream commit 5088eb4092df12d701af8e0e92860b7186365279 ]

The host CTRL (runlatch) value is not restored after guest exit. The
host CTRL should always be 1 except in CPU idle code, so this can result
in the host running with runlatch clear, and potentially switching to
a different vCPU which then runs with runlatch clear as well.

This has little effect on P9 machines, CTRL is only responsible for some
PMU counter logic in the host and so other than corner cases of software
relying on that, or explicitly reading the runlatch value (Linux does
not appear to be affected but it's possible non-Linux guests could be),
there should be no execution correctness problem, though it could be
used as a covert channel between guests.

There may be microcontrollers, firmware or monitoring tools that sample
the runlatch value out-of-band, however since the register is writable
by guests, these values would (should) not be relied upon for correct
operation of the host, so suboptimal performance or incorrect reporting
should be the worst problem.

Fixes: 95a6432ce9 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210412014845.1517916-2-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:44:28 +02:00
Cédric Le Goater
8121f35cc6 KVM: PPC: Make the VMX instruction emulation routines static
[ Upstream commit 9236f57a9e51c72ce426ccd2e53e123de7196a0f ]

These are only used locally. It fixes these W=1 compile errors :

../arch/powerpc/kvm/powerpc.c:1521:5: error: no previous prototype for ‘kvmppc_get_vmx_dword’ [-Werror=missing-prototypes]
 1521 | int kvmppc_get_vmx_dword(struct kvm_vcpu *vcpu, int index, u64 *val)
      |     ^~~~~~~~~~~~~~~~~~~~
../arch/powerpc/kvm/powerpc.c:1539:5: error: no previous prototype for ‘kvmppc_get_vmx_word’ [-Werror=missing-prototypes]
 1539 | int kvmppc_get_vmx_word(struct kvm_vcpu *vcpu, int index, u64 *val)
      |     ^~~~~~~~~~~~~~~~~~~
../arch/powerpc/kvm/powerpc.c:1557:5: error: no previous prototype for ‘kvmppc_get_vmx_hword’ [-Werror=missing-prototypes]
 1557 | int kvmppc_get_vmx_hword(struct kvm_vcpu *vcpu, int index, u64 *val)
      |     ^~~~~~~~~~~~~~~~~~~~
../arch/powerpc/kvm/powerpc.c:1575:5: error: no previous prototype for ‘kvmppc_get_vmx_byte’ [-Werror=missing-prototypes]
 1575 | int kvmppc_get_vmx_byte(struct kvm_vcpu *vcpu, int index, u64 *val)
      |     ^~~~~~~~~~~~~~~~~~~

Fixes: acc9eb9305 ("KVM: PPC: Reimplement LOAD_VMX/STORE_VMX instruction mmio emulation with analyse_instr() input")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210104143206.695198-19-clg@kaod.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-04 10:26:31 +01:00
Cédric Le Goater
45b5f4b1b4 KVM: PPC: Book3S HV: XIVE: Fix possible oops when accessing ESB page
commit 75b49620267c700f0a07fec7f27f69852db70e46 upstream.

When accessing the ESB page of a source interrupt, the fault handler
will retrieve the page address from the XIVE interrupt 'xive_irq_data'
structure. If the associated KVM XIVE interrupt is not valid, that is
not allocated at the HW level for some reason, the fault handler will
dereference a NULL pointer leading to the oops below :

  WARNING: CPU: 40 PID: 59101 at arch/powerpc/kvm/book3s_xive_native.c:259 xive_native_esb_fault+0xe4/0x240 [kvm]
  CPU: 40 PID: 59101 Comm: qemu-system-ppc Kdump: loaded Tainted: G        W        --------- -  - 4.18.0-240.el8.ppc64le #1
  NIP:  c00800000e949fac LR: c00000000044b164 CTR: c00800000e949ec8
  REGS: c000001f69617840 TRAP: 0700   Tainted: G        W        --------- -  -  (4.18.0-240.el8.ppc64le)
  MSR:  9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 44044282  XER: 00000000
  CFAR: c00000000044b160 IRQMASK: 0
  GPR00: c00000000044b164 c000001f69617ac0 c00800000e96e000 c000001f69617c10
  GPR04: 05faa2b21e000080 0000000000000000 0000000000000005 ffffffffffffffff
  GPR08: 0000000000000000 0000000000000001 0000000000000000 0000000000000001
  GPR12: c00800000e949ec8 c000001ffffd3400 0000000000000000 0000000000000000
  GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
  GPR20: 0000000000000000 0000000000000000 c000001f5c065160 c000000001c76f90
  GPR24: c000001f06f20000 c000001f5c065100 0000000000000008 c000001f0eb98c78
  GPR28: c000001dcab40000 c000001dcab403d8 c000001f69617c10 0000000000000011
  NIP [c00800000e949fac] xive_native_esb_fault+0xe4/0x240 [kvm]
  LR [c00000000044b164] __do_fault+0x64/0x220
  Call Trace:
  [c000001f69617ac0] [0000000137a5dc20] 0x137a5dc20 (unreliable)
  [c000001f69617b50] [c00000000044b164] __do_fault+0x64/0x220
  [c000001f69617b90] [c000000000453838] do_fault+0x218/0x930
  [c000001f69617bf0] [c000000000456f50] __handle_mm_fault+0x350/0xdf0
  [c000001f69617cd0] [c000000000457b1c] handle_mm_fault+0x12c/0x310
  [c000001f69617d10] [c00000000007ef44] __do_page_fault+0x264/0xbb0
  [c000001f69617df0] [c00000000007f8c8] do_page_fault+0x38/0xd0
  [c000001f69617e30] [c00000000000a714] handle_page_fault+0x18/0x38
  Instruction dump:
  40c2fff0 7c2004ac 2fa90000 409e0118 73e90001 41820080 e8bd0008 7c2004ac
  7ca90074 39400000 915c0000 7929d182 <0b090000> 2fa50000 419e0080 e89e0018
  ---[ end trace 66c6ff034c53f64f ]---
  xive-kvm: xive_native_esb_fault: accessing invalid ESB page for source 8 !

Fix that by checking the validity of the KVM XIVE interrupt structure.

Fixes: 6520ca64cd ("KVM: PPC: Book3S HV: XIVE: Add a mapping for the source ESB pages")
Cc: stable@vger.kernel.org # v5.2+
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201105134713.656160-1-clg@kaod.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-02 08:49:46 +01:00
Fabiano Rosas
9b58c55ba8 KVM: PPC: Book3S HV: Do not allocate HPT for a nested guest
[ Upstream commit 05e6295dc7de859c9d56334805485c4d20bebf25 ]

The current nested KVM code does not support HPT guests. This is
informed/enforced in some ways:

- Hosts < P9 will not be able to enable the nested HV feature;

- The nested hypervisor MMU capabilities will not contain
  KVM_CAP_PPC_MMU_HASH_V3;

- QEMU reflects the MMU capabilities in the
  'ibm,arch-vec-5-platform-support' device-tree property;

- The nested guest, at 'prom_parse_mmu_model' ignores the
  'disable_radix' kernel command line option if HPT is not supported;

- The KVM_PPC_CONFIGURE_V3_MMU ioctl will fail if trying to use HPT.

There is, however, still a way to start a HPT guest by using
max-compat-cpu=power8 at the QEMU machine options. This leads to the
guest being set to use hash after QEMU calls the KVM_PPC_ALLOCATE_HTAB
ioctl.

With the guest set to hash, the nested hypervisor goes through the
entry path that has no knowledge of nesting (kvmppc_run_vcpu) and
crashes when it tries to execute an hypervisor-privileged (mtspr
HDEC) instruction at __kvmppc_vcore_entry:

root@L1:~ $ qemu-system-ppc64 -machine pseries,max-cpu-compat=power8 ...

<snip>
[  538.543303] CPU: 83 PID: 25185 Comm: CPU 0/KVM Not tainted 5.9.0-rc4 #1
[  538.543355] NIP:  c00800000753f388 LR: c00800000753f368 CTR: c0000000001e5ec0
[  538.543417] REGS: c0000013e91e33b0 TRAP: 0700   Not tainted  (5.9.0-rc4)
[  538.543470] MSR:  8000000002843033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE>  CR: 22422882  XER: 20040000
[  538.543546] CFAR: c00800000753f4b0 IRQMASK: 3
               GPR00: c0080000075397a0 c0000013e91e3640 c00800000755e600 0000000080000000
               GPR04: 0000000000000000 c0000013eab19800 c000001394de0000 00000043a054db72
               GPR08: 00000000003b1652 0000000000000000 0000000000000000 c0080000075502e0
               GPR12: c0000000001e5ec0 c0000007ffa74200 c0000013eab19800 0000000000000008
               GPR16: 0000000000000000 c00000139676c6c0 c000000001d23948 c0000013e91e38b8
               GPR20: 0000000000000053 0000000000000000 0000000000000001 0000000000000000
               GPR24: 0000000000000001 0000000000000001 0000000000000000 0000000000000001
               GPR28: 0000000000000001 0000000000000053 c0000013eab19800 0000000000000001
[  538.544067] NIP [c00800000753f388] __kvmppc_vcore_entry+0x90/0x104 [kvm_hv]
[  538.544121] LR [c00800000753f368] __kvmppc_vcore_entry+0x70/0x104 [kvm_hv]
[  538.544173] Call Trace:
[  538.544196] [c0000013e91e3640] [c0000013e91e3680] 0xc0000013e91e3680 (unreliable)
[  538.544260] [c0000013e91e3820] [c0080000075397a0] kvmppc_run_core+0xbc8/0x19d0 [kvm_hv]
[  538.544325] [c0000013e91e39e0] [c00800000753d99c] kvmppc_vcpu_run_hv+0x404/0xc00 [kvm_hv]
[  538.544394] [c0000013e91e3ad0] [c0080000072da4fc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[  538.544472] [c0000013e91e3af0] [c0080000072d61b8] kvm_arch_vcpu_ioctl_run+0x310/0x420 [kvm]
[  538.544539] [c0000013e91e3b80] [c0080000072c7450] kvm_vcpu_ioctl+0x298/0x778 [kvm]
[  538.544605] [c0000013e91e3ce0] [c0000000004b8c2c] sys_ioctl+0x1dc/0xc90
[  538.544662] [c0000013e91e3dc0] [c00000000002f9a4] system_call_exception+0xe4/0x1c0
[  538.544726] [c0000013e91e3e20] [c00000000000d140] system_call_common+0xf0/0x27c
[  538.544787] Instruction dump:
[  538.544821] f86d1098 60000000 60000000 48000099 e8ad0fe8 e8c500a0 e9264140 75290002
[  538.544886] 7d1602a6 7cec42a6 40820008 7d0807b4 <7d164ba6> 7d083a14 f90d10a0 480104fd
[  538.544953] ---[ end trace 74423e2b948c2e0c ]---

This patch makes the KVM_PPC_ALLOCATE_HTAB ioctl fail when running in
the nested hypervisor, causing QEMU to abort.

Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05 11:43:21 +01:00
Paul Mackerras
ad9940e377 KVM: PPC: Book3S HV: Close race with page faults around memslot flushes
[ Upstream commit 11362b1befeadaae4d159a8cddcdaf6b8afe08f9 ]

There is a potential race condition between hypervisor page faults
and flushing a memslot.  It is possible for a page fault to read the
memslot before a memslot is updated and then write a PTE to the
partition-scoped page tables after kvmppc_radix_flush_memslot has
completed.  (Note that this race has never been explicitly observed.)

To close this race, it is sufficient to increment the MMU sequence
number while the kvm->mmu_lock is held.  That will cause
mmu_notifier_retry() to return true, and the page fault will then
return to the guest without inserting a PTE.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:18:05 +02:00
Gustavo Romero
5d09e3edf5 KVM: PPC: Book3S HV: Treat TM-related invalid form instructions on P9 like the valid ones
[ Upstream commit 1dff3064c764b5a51c367b949b341d2e38972bec ]

On P9 DD2.2 due to a CPU defect some TM instructions need to be emulated by
KVM. This is handled at first by the hardware raising a softpatch interrupt
when certain TM instructions that need KVM assistance are executed in the
guest. Althought some TM instructions per Power ISA are invalid forms they
can raise a softpatch interrupt too. For instance, 'tresume.' instruction
as defined in the ISA must have bit 31 set (1), but an instruction that
matches 'tresume.' PO and XO opcode fields but has bit 31 not set (0), like
0x7cfe9ddc, also raises a softpatch interrupt. Similarly for 'treclaim.'
and 'trechkpt.' instructions with bit 31 = 0, i.e. 0x7c00075c and
0x7c0007dc, respectively. Hence, if a code like the following is executed
in the guest it will raise a softpatch interrupt just like a 'tresume.'
when the TM facility is enabled ('tabort. 0' in the example is used only
to enable the TM facility):

int main() { asm("tabort. 0; .long 0x7cfe9ddc;"); }

Currently in such a case KVM throws a complete trace like:

[345523.705984] WARNING: CPU: 24 PID: 64413 at arch/powerpc/kvm/book3s_hv_tm.c:211 kvmhv_p9_tm_emulation+0x68/0x620 [kvm_hv]
[345523.705985] Modules linked in: kvm_hv(E) xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp ip6table_mangle ip6table_nat
iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ebtable_filter ebtables ip6table_filter
ip6_tables iptable_filter bridge stp llc sch_fq_codel ipmi_powernv at24 vmx_crypto ipmi_devintf ipmi_msghandler
ibmpowernv uio_pdrv_genirq kvm opal_prd uio leds_powernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp
libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456
async_raid6_recov async_memcpy async_pq async_xor async_tx libcrc32c xor raid6_pq raid1 raid0 multipath linear tg3
crct10dif_vpmsum crc32c_vpmsum ipr [last unloaded: kvm_hv]
[345523.706030] CPU: 24 PID: 64413 Comm: CPU 0/KVM Tainted: G        W   E     5.5.0+ #1
[345523.706031] NIP:  c0080000072cb9c0 LR: c0080000072b5e80 CTR: c0080000085c7850
[345523.706034] REGS: c000000399467680 TRAP: 0700   Tainted: G        W   E      (5.5.0+)
[345523.706034] MSR:  900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]>  CR: 24022428  XER: 00000000
[345523.706042] CFAR: c0080000072b5e7c IRQMASK: 0
                GPR00: c0080000072b5e80 c000000399467910 c0080000072db500 c000000375ccc720
                GPR04: c000000375ccc720 00000003fbec0000 0000a10395dda5a6 0000000000000000
                GPR08: 000000007cfe9ddc 7cfe9ddc000005dc 7cfe9ddc7c0005dc c0080000072cd530
                GPR12: c0080000085c7850 c0000003fffeb800 0000000000000001 00007dfb737f0000
                GPR16: c0002001edcca558 0000000000000000 0000000000000000 0000000000000001
                GPR20: c000000001b21258 c0002001edcca558 0000000000000018 0000000000000000
                GPR24: 0000000001000000 ffffffffffffffff 0000000000000001 0000000000001500
                GPR28: c0002001edcc4278 c00000037dd80000 800000050280f033 c000000375ccc720
[345523.706062] NIP [c0080000072cb9c0] kvmhv_p9_tm_emulation+0x68/0x620 [kvm_hv]
[345523.706065] LR [c0080000072b5e80] kvmppc_handle_exit_hv.isra.53+0x3e8/0x798 [kvm_hv]
[345523.706066] Call Trace:
[345523.706069] [c000000399467910] [c000000399467940] 0xc000000399467940 (unreliable)
[345523.706071] [c000000399467950] [c000000399467980] 0xc000000399467980
[345523.706075] [c0000003994679f0] [c0080000072bd1c4] kvmhv_run_single_vcpu+0xa1c/0xb80 [kvm_hv]
[345523.706079] [c000000399467ac0] [c0080000072bd8e0] kvmppc_vcpu_run_hv+0x5b8/0xb00 [kvm_hv]
[345523.706087] [c000000399467b90] [c0080000085c93cc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[345523.706095] [c000000399467bb0] [c0080000085c582c] kvm_arch_vcpu_ioctl_run+0x244/0x420 [kvm]
[345523.706101] [c000000399467c40] [c0080000085b7498] kvm_vcpu_ioctl+0x3d0/0x7b0 [kvm]
[345523.706105] [c000000399467db0] [c0000000004adf9c] ksys_ioctl+0x13c/0x170
[345523.706107] [c000000399467e00] [c0000000004adff8] sys_ioctl+0x28/0x80
[345523.706111] [c000000399467e20] [c00000000000b278] system_call+0x5c/0x68
[345523.706112] Instruction dump:
[345523.706114] 419e0390 7f8a4840 409d0048 6d497c00 2f89075d 419e021c 6d497c00 2f8907dd
[345523.706119] 419e01c0 6d497c00 2f8905dd 419e00a4 <0fe00000> 38210040 38600000 ebc1fff0

and then treats the executed instruction as a 'nop'.

However the POWER9 User's Manual, in section "4.6.10 Book II Invalid
Forms", informs that for TM instructions bit 31 is in fact ignored, thus
for the TM-related invalid forms ignoring bit 31 and handling them like the
valid forms is an acceptable way to handle them. POWER8 behaves the same
way too.

This commit changes the handling of the cases here described by treating
the TM-related invalid forms that can generate a softpatch interrupt
just like their valid forms (w/ bit 31 = 1) instead of as a 'nop' and by
gently reporting any other unrecognized case to the host and treating it as
illegal instruction instead of throwing a trace and treating it as a 'nop'.

Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Acked-By: Michael Neuling <mikey@neuling.org>
Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:44 +02:00
Will Deacon
e1818ffcca KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()
commit fdfe7cbd58806522e799e2a50a15aee7f2cbb7b6 upstream.

The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.

Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.

Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-2-will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-26 10:41:08 +02:00
Aneesh Kumar K.V
1a570b8fae powerpc/kvm/book3s64: Fix kernel crash with nested kvm & DEBUG_VIRTUAL
[ Upstream commit c1ed1754f271f6b7acb1bfdc8cfb62220fbed423 ]

With CONFIG_DEBUG_VIRTUAL=y, __pa() checks for addr value and if it's
less than PAGE_OFFSET it leads to a BUG().

  #define __pa(x)
  ({
  	VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET);
  	(unsigned long)(x) & 0x0fffffffffffffffUL;
  })

  kernel BUG at arch/powerpc/kvm/book3s_64_mmu_radix.c:43!
  cpu 0x70: Vector: 700 (Program Check) at [c0000018a2187360]
      pc: c000000000161b30: __kvmhv_copy_tofrom_guest_radix+0x130/0x1f0
      lr: c000000000161d5c: kvmhv_copy_from_guest_radix+0x3c/0x80
  ...
  kvmhv_copy_from_guest_radix+0x3c/0x80
  kvmhv_load_from_eaddr+0x48/0xc0
  kvmppc_ld+0x98/0x1e0
  kvmppc_load_last_inst+0x50/0x90
  kvmppc_hv_emulate_mmio+0x288/0x2b0
  kvmppc_book3s_radix_page_fault+0xd8/0x2b0
  kvmppc_book3s_hv_page_fault+0x37c/0x1050
  kvmppc_vcpu_run_hv+0xbb8/0x1080
  kvmppc_vcpu_run+0x34/0x50
  kvm_arch_vcpu_ioctl_run+0x2fc/0x410
  kvm_vcpu_ioctl+0x2b4/0x8f0
  ksys_ioctl+0xf4/0x150
  sys_ioctl+0x28/0x80
  system_call_exception+0x104/0x1d0
  system_call_common+0xe8/0x214

kvmhv_copy_tofrom_guest_radix() uses a NULL value for to/from to
indicate direction of copy.

Avoid calling __pa() if the value is NULL to avoid the BUG().

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Massage change log a bit to mention CONFIG_DEBUG_VIRTUAL]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611120159.680284-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-16 08:16:35 +02:00
Qian Cai
e5497842e2 KVM: PPC: Book3S: Fix some RCU-list locks
[ Upstream commit ab8b65be183180c3eef405d449163964ecc4b571 ]

It is unsafe to traverse kvm->arch.spapr_tce_tables and
stt->iommu_tables without the RCU read lock held. Also, add
cond_resched_rcu() in places with the RCU read lock held that could take
a while to finish.

 arch/powerpc/kvm/book3s_64_vio.c:76 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 no locks held by qemu-kvm/4265.

 stack backtrace:
 CPU: 96 PID: 4265 Comm: qemu-kvm Not tainted 5.7.0-rc4-next-20200508+ #2
 Call Trace:
 [c000201a8690f720] [c000000000715948] dump_stack+0xfc/0x174 (unreliable)
 [c000201a8690f770] [c0000000001d9470] lockdep_rcu_suspicious+0x140/0x164
 [c000201a8690f7f0] [c008000010b9fb48] kvm_spapr_tce_release_iommu_group+0x1f0/0x220 [kvm]
 [c000201a8690f870] [c008000010b8462c] kvm_spapr_tce_release_vfio_group+0x54/0xb0 [kvm]
 [c000201a8690f8a0] [c008000010b84710] kvm_vfio_destroy+0x88/0x140 [kvm]
 [c000201a8690f8f0] [c008000010b7d488] kvm_put_kvm+0x370/0x600 [kvm]
 [c000201a8690f990] [c008000010b7e3c0] kvm_vm_release+0x38/0x60 [kvm]
 [c000201a8690f9c0] [c0000000005223f4] __fput+0x124/0x330
 [c000201a8690fa20] [c000000000151cd8] task_work_run+0xb8/0x130
 [c000201a8690fa70] [c0000000001197e8] do_exit+0x4e8/0xfa0
 [c000201a8690fb70] [c00000000011a374] do_group_exit+0x64/0xd0
 [c000201a8690fbb0] [c000000000132c90] get_signal+0x1f0/0x1200
 [c000201a8690fcc0] [c000000000020690] do_notify_resume+0x130/0x3c0
 [c000201a8690fda0] [c000000000038d64] syscall_exit_prepare+0x1a4/0x280
 [c000201a8690fe20] [c00000000000c8f8] system_call_common+0xf8/0x278

 ====
 arch/powerpc/kvm/book3s_64_vio.c:368 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 2 locks held by qemu-kvm/4264:
  #0: c000201ae2d000d8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xdc/0x950 [kvm]
  #1: c000200c9ed0c468 (&kvm->srcu){....}-{0:0}, at: kvmppc_h_put_tce+0x88/0x340 [kvm]

 ====
 arch/powerpc/kvm/book3s_64_vio.c:108 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 1 lock held by qemu-kvm/4257:
  #0: c000200b1b363a40 (&kv->lock){+.+.}-{3:3}, at: kvm_vfio_set_attr+0x598/0x6c0 [kvm]

 ====
 arch/powerpc/kvm/book3s_64_vio.c:146 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 1 lock held by qemu-kvm/4257:
  #0: c000200b1b363a40 (&kv->lock){+.+.}-{3:3}, at: kvm_vfio_set_attr+0x598/0x6c0 [kvm]

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-24 17:50:34 +02:00
Qian Cai
fd1a1089ae KVM: PPC: Book3S HV: Ignore kmemleak false positives
[ Upstream commit 0aca8a5575544bd21b3363058afb8f1e81505150 ]

kvmppc_pmd_alloc() and kvmppc_pte_alloc() allocate some memory but then
pud_populate() and pmd_populate() will use __pa() to reference the newly
allocated memory.

Since kmemleak is unable to track the physical memory resulting in false
positives, silence those by using kmemleak_ignore().

unreferenced object 0xc000201c382a1000 (size 4096):
 comm "qemu-kvm", pid 124828, jiffies 4295733767 (age 341.250s)
 hex dump (first 32 bytes):
   c0 00 20 09 f4 60 03 87 c0 00 20 10 72 a0 03 87  .. ..`.... .r...
   c0 00 20 0e 13 a0 03 87 c0 00 20 1b dc c0 03 87  .. ....... .....
 backtrace:
   [<000000004cc2790f>] kvmppc_create_pte+0x838/0xd20 [kvm_hv]
   kvmppc_pmd_alloc at arch/powerpc/kvm/book3s_64_mmu_radix.c:366
   (inlined by) kvmppc_create_pte at arch/powerpc/kvm/book3s_64_mmu_radix.c:590
   [<00000000d123c49a>] kvmppc_book3s_instantiate_page+0x2e0/0x8c0 [kvm_hv]
   [<00000000bb549087>] kvmppc_book3s_radix_page_fault+0x1b4/0x2b0 [kvm_hv]
   [<0000000086dddc0e>] kvmppc_book3s_hv_page_fault+0x214/0x12a0 [kvm_hv]
   [<000000005ae9ccc2>] kvmppc_vcpu_run_hv+0xc5c/0x15f0 [kvm_hv]
   [<00000000d22162ff>] kvmppc_vcpu_run+0x34/0x48 [kvm]
   [<00000000d6953bc4>] kvm_arch_vcpu_ioctl_run+0x314/0x420 [kvm]
   [<000000002543dd54>] kvm_vcpu_ioctl+0x33c/0x950 [kvm]
   [<0000000048155cd6>] ksys_ioctl+0xd8/0x130
   [<0000000041ffeaa7>] sys_ioctl+0x28/0x40
   [<000000004afc4310>] system_call_exception+0x114/0x1e0
   [<00000000fb70a873>] system_call_common+0xf0/0x278
unreferenced object 0xc0002001f0c03900 (size 256):
 comm "qemu-kvm", pid 124830, jiffies 4295735235 (age 326.570s)
 hex dump (first 32 bytes):
   c0 00 20 10 fa a0 03 87 c0 00 20 10 fa a1 03 87  .. ....... .....
   c0 00 20 10 fa a2 03 87 c0 00 20 10 fa a3 03 87  .. ....... .....
 backtrace:
   [<0000000023f675b8>] kvmppc_create_pte+0x854/0xd20 [kvm_hv]
   kvmppc_pte_alloc at arch/powerpc/kvm/book3s_64_mmu_radix.c:356
   (inlined by) kvmppc_create_pte at arch/powerpc/kvm/book3s_64_mmu_radix.c:593
   [<00000000d123c49a>] kvmppc_book3s_instantiate_page+0x2e0/0x8c0 [kvm_hv]
   [<00000000bb549087>] kvmppc_book3s_radix_page_fault+0x1b4/0x2b0 [kvm_hv]
   [<0000000086dddc0e>] kvmppc_book3s_hv_page_fault+0x214/0x12a0 [kvm_hv]
   [<000000005ae9ccc2>] kvmppc_vcpu_run_hv+0xc5c/0x15f0 [kvm_hv]
   [<00000000d22162ff>] kvmppc_vcpu_run+0x34/0x48 [kvm]
   [<00000000d6953bc4>] kvm_arch_vcpu_ioctl_run+0x314/0x420 [kvm]
   [<000000002543dd54>] kvm_vcpu_ioctl+0x33c/0x950 [kvm]
   [<0000000048155cd6>] ksys_ioctl+0xd8/0x130
   [<0000000041ffeaa7>] sys_ioctl+0x28/0x40
   [<000000004afc4310>] system_call_exception+0x114/0x1e0
   [<00000000fb70a873>] system_call_common+0xf0/0x278

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-24 17:50:34 +02:00
Michael Roth
ffbad91b66 KVM: PPC: Book3S HV: Fix H_CEDE return code for nested guests
[ Upstream commit 1f50cc1705350a4697923203fedd7d8fb1087fe2 ]

The h_cede_tm kvm-unit-test currently fails when run inside an L1 guest
via the guest/nested hypervisor.

  ./run-tests.sh -v
  ...
  TESTNAME=h_cede_tm TIMEOUT=90s ACCEL= ./powerpc/run powerpc/tm.elf -smp 2,threads=2 -machine cap-htm=on -append "h_cede_tm"
  FAIL h_cede_tm (2 tests, 1 unexpected failures)

While the test relates to transactional memory instructions, the actual
failure is due to the return code of the H_CEDE hypercall, which is
reported as 224 instead of 0. This happens even when no TM instructions
are issued.

224 is the value placed in r3 to execute a hypercall for H_CEDE, and r3
is where the caller expects the return code to be placed upon return.

In the case of guest running under a nested hypervisor, issuing H_CEDE
causes a return from H_ENTER_NESTED. In this case H_CEDE is
specially-handled immediately rather than later in
kvmppc_pseries_do_hcall() as with most other hcalls, but we forget to
set the return code for the caller, hence why kvm-unit-test sees the
224 return code and reports an error.

Guest kernels generally don't check the return value of H_CEDE, so
that likely explains why this hasn't caused issues outside of
kvm-unit-tests so far.

Fix this by setting r3 to 0 after we finish processing the H_CEDE.

RHBZ: 1778556

Fixes: 4bad77799f ("KVM: PPC: Book3S HV: Handle hypercalls correctly when nested")
Cc: linuxppc-dev@ozlabs.org
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-23 10:36:32 +02:00
zhengbin
88cf251d3c KVM: PPC: Remove set but not used variable 'ra', 'rs', 'rt'
[ Upstream commit 4de0a8355463e068e443b48eb5ae32370155368b ]

Fixes gcc '-Wunused-but-set-variable' warning:

arch/powerpc/kvm/emulate_loadstore.c: In function kvmppc_emulate_loadstore:
arch/powerpc/kvm/emulate_loadstore.c:87:6: warning: variable ra set but not used [-Wunused-but-set-variable]
arch/powerpc/kvm/emulate_loadstore.c: In function kvmppc_emulate_loadstore:
arch/powerpc/kvm/emulate_loadstore.c:87:10: warning: variable rs set but not used [-Wunused-but-set-variable]
arch/powerpc/kvm/emulate_loadstore.c: In function kvmppc_emulate_loadstore:
arch/powerpc/kvm/emulate_loadstore.c:87:14: warning: variable rt set but not used [-Wunused-but-set-variable]

They are not used since commit 2b33cb585f ("KVM: PPC: Reimplement
LOAD_FP/STORE_FP instruction mmio emulation with analyse_instr() input")

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-24 08:36:51 +01:00
Sean Christopherson
7426ddf01f KVM: Use vcpu-specific gva->hva translation when querying host page size
[ Upstream commit f9b84e19221efc5f493156ee0329df3142085f28 ]

Use kvm_vcpu_gfn_to_hva() when retrieving the host page size so that the
correct set of memslots is used when handling x86 page faults in SMM.

Fixes: 54bf36aac5 ("KVM: x86: use vcpu-specific functions to read/write/translate GFNs")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-11 04:35:54 -08:00
Sean Christopherson
9213699efd KVM: PPC: Book3S PR: Free shared page if mmu initialization fails
commit cb10bf9194f4d2c5d830eddca861f7ca0fecdbb4 upstream.

Explicitly free the shared page if kvmppc_mmu_init() fails during
kvmppc_core_vcpu_create(), as the page is freed only in
kvmppc_core_vcpu_free(), which is not reached via kvm_vcpu_uninit().

Fixes: 96bc451a15 ("KVM: PPC: Introduce shared page")
Cc: stable@vger.kernel.org
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11 04:35:39 -08:00
Sean Christopherson
b2301deda8 KVM: PPC: Book3S HV: Uninit vCPU if vcore creation fails
commit 1a978d9d3e72ddfa40ac60d26301b154247ee0bc upstream.

Call kvm_vcpu_uninit() if vcore creation fails to avoid leaking any
resources allocated by kvm_vcpu_init(), i.e. the vcpu->run page.

Fixes: 371fefd6f2 ("KVM: PPC: Allow book3s_hv guests to use SMT processor modes")
Cc: stable@vger.kernel.org
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11 04:35:39 -08:00
Marcus Comstedt
0c304e5368 KVM: PPC: Book3S HV: Fix regression on big endian hosts
commit 228b607d8ea1b7d4561945058d5692709099d432 upstream.

VCPU_CR is the offset of arch.regs.ccr in kvm_vcpu.
arch/powerpc/include/asm/kvm_host.h defines arch.regs as a struct
pt_regs, and arch/powerpc/include/asm/ptrace.h defines the ccr field
of pt_regs as "unsigned long ccr".  Since unsigned long is 64 bits, a
64-bit load needs to be used to load it, unless an endianness specific
correction offset is added to access the desired subpart.  In this
case there is no reason to _not_ use a 64 bit load though.

Fixes: 6c85b7bc63 ("powerpc/kvm: Use UV_RETURN ucall to return to ultravisor")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Marcus Comstedt <marcus@mc.pp.se>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191215094900.46740-1-marcus@mc.pp.se
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-31 16:46:21 +01:00
Greg Kurz
ff6900f46d KVM: PPC: Book3S HV: XIVE: Set kvm->arch.xive when VPs are allocated
commit e7d71c943040c23f2fd042033d319f56e84f845b upstream.

If we cannot allocate the XIVE VPs in OPAL, the creation of a XIVE or
XICS-on-XIVE device is aborted as expected, but we leave kvm->arch.xive
set forever since the release method isn't called in this case. Any
subsequent tentative to create a XIVE or XICS-on-XIVE for this VM will
thus always fail (DoS). This is a problem for QEMU since it destroys
and re-creates these devices when the VM is reset: the VM would be
restricted to using the much slower emulated XIVE or XICS forever.

As an alternative to adding rollback, do not assign kvm->arch.xive before
making sure the XIVE VPs are allocated in OPAL.

Cc: stable@vger.kernel.org # v5.2
Fixes: 5422e95103 ("KVM: PPC: Book3S HV: XIVE: Replace the 'destroy' method by a 'release' method")
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-13 08:42:59 +01:00
Greg Kurz
88c494172b KVM: PPC: Book3S HV: XIVE: Fix potential page leak on error path
commit 30486e72093ea2e594f44876b7a445c219449bce upstream.

We need to check the host page size is big enough to accomodate the
EQ. Let's do this before taking a reference on the EQ page to avoid
a potential leak if the check fails.

Cc: stable@vger.kernel.org # v5.2
Fixes: 13ce3297c5 ("KVM: PPC: Book3S HV: XIVE: Add controls for the EQ configuration")
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-13 08:42:58 +01:00
Greg Kurz
97c9c012fe KVM: PPC: Book3S HV: XIVE: Free previous EQ page when setting up a new one
commit 31a88c82b466d2f31a44e21c479f45b4732ccfd0 upstream.

The EQ page is allocated by the guest and then passed to the hypervisor
with the H_INT_SET_QUEUE_CONFIG hcall. A reference is taken on the page
before handing it over to the HW. This reference is dropped either when
the guest issues the H_INT_RESET hcall or when the KVM device is released.
But, the guest can legitimately call H_INT_SET_QUEUE_CONFIG several times,
either to reset the EQ (vCPU hot unplug) or to set a new EQ (guest reboot).
In both cases the existing EQ page reference is leaked because we simply
overwrite it in the XIVE queue structure without calling put_page().

This is especially visible when the guest memory is backed with huge pages:
start a VM up to the guest userspace, either reboot it or unplug a vCPU,
quit QEMU. The leak is observed by comparing the value of HugePages_Free in
/proc/meminfo before and after the VM is run.

Ideally we'd want the XIVE code to handle the EQ page de-allocation at the
platform level. This isn't the case right now because the various XIVE
drivers have different allocation needs. It could maybe worth introducing
hooks for this purpose instead of exposing XIVE internals to the drivers,
but this is certainly a huge work to be done later.

In the meantime, for easier backport, fix both vCPU unplug and guest reboot
leaks by introducing a wrapper around xive_native_configure_queue() that
does the necessary cleanup.

Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v5.2
Fixes: 13ce3297c5 ("KVM: PPC: Book3S HV: XIVE: Add controls for the EQ configuration")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Tested-by: Lijun Pan <ljp@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-13 08:42:58 +01:00
Michael Ellerman
fcddcfa746 KVM: PPC: Book3S HV: Flush link stack on guest exit to host kernel
commit af2e8c68b9c5403f77096969c516f742f5bb29e0 upstream.

On some systems that are vulnerable to Spectre v2, it is up to
software to flush the link stack (return address stack), in order to
protect against Spectre-RSB.

When exiting from a guest we do some house keeping and then
potentially exit to C code which is several stack frames deep in the
host kernel. We will then execute a series of returns without
preceeding calls, opening up the possiblity that the guest could have
poisoned the link stack, and direct speculative execution of the host
to a gadget of some sort.

To prevent this we add a flush of the link stack on exit from a guest.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29 10:10:32 +01:00
Greg Kurz
12ade69c1e KVM: PPC: Book3S HV: XIVE: Ensure VP isn't already in use
Connecting a vCPU to a XIVE KVM device means establishing a 1:1
association between a vCPU id and the offset (VP id) of a VP
structure within a fixed size block of VPs. We currently try to
enforce the 1:1 relationship by checking that a vCPU with the
same id isn't already connected. This is good but unfortunately
not enough because we don't map VP ids to raw vCPU ids but to
packed vCPU ids, and the packing function kvmppc_pack_vcpu_id()
isn't bijective by design. We got away with it because QEMU passes
vCPU ids that fit well in the packing pattern. But nothing prevents
userspace to come up with a forged vCPU id resulting in a packed id
collision which causes the KVM device to associate two vCPUs to the
same VP. This greatly confuses the irq layer and ultimately crashes
the kernel, as shown below.

Example: a guest with 1 guest thread per core, a core stride of
8 and 300 vCPUs has vCPU ids 0,8,16...2392. If QEMU is patched to
inject at some point an invalid vCPU id 348, which is the packed
version of itself and 2392, we get:

genirq: Flags mismatch irq 199. 00010000 (kvm-2-2392) vs. 00010000 (kvm-2-348)
CPU: 24 PID: 88176 Comm: qemu-system-ppc Not tainted 5.3.0-xive-nr-servers-5.3-gku+ #38
Call Trace:
[c000003f7f9937e0] [c000000000c0110c] dump_stack+0xb0/0xf4 (unreliable)
[c000003f7f993820] [c0000000001cb480] __setup_irq+0xa70/0xad0
[c000003f7f9938d0] [c0000000001cb75c] request_threaded_irq+0x13c/0x260
[c000003f7f993940] [c00800000d44e7ac] kvmppc_xive_attach_escalation+0x104/0x270 [kvm]
[c000003f7f9939d0] [c00800000d45013c] kvmppc_xive_connect_vcpu+0x424/0x620 [kvm]
[c000003f7f993ac0] [c00800000d444428] kvm_arch_vcpu_ioctl+0x260/0x448 [kvm]
[c000003f7f993b90] [c00800000d43593c] kvm_vcpu_ioctl+0x154/0x7c8 [kvm]
[c000003f7f993d00] [c0000000004840f0] do_vfs_ioctl+0xe0/0xc30
[c000003f7f993db0] [c000000000484d44] ksys_ioctl+0x104/0x120
[c000003f7f993e00] [c000000000484d88] sys_ioctl+0x28/0x80
[c000003f7f993e20] [c00000000000b278] system_call+0x5c/0x68
xive-kvm: Failed to request escalation interrupt for queue 0 of VCPU 2392
------------[ cut here ]------------
remove_proc_entry: removing non-empty directory 'irq/199', leaking at least 'kvm-2-348'
WARNING: CPU: 24 PID: 88176 at /home/greg/Work/linux/kernel-kvm-ppc/fs/proc/generic.c:684 remove_proc_entry+0x1ec/0x200
Modules linked in: kvm_hv kvm dm_mod vhost_net vhost tap xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter squashfs loop fuse i2c_dev sg ofpart ocxl powernv_flash at24 xts mtd uio_pdrv_genirq vmx_crypto opal_prd ipmi_powernv uio ipmi_devintf ipmi_msghandler ibmpowernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear sd_mod ast i2c_algo_bit drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci libata tg3 drm_panel_orientation_quirks [last unloaded: kvm]
CPU: 24 PID: 88176 Comm: qemu-system-ppc Not tainted 5.3.0-xive-nr-servers-5.3-gku+ #38
NIP:  c00000000053b0cc LR: c00000000053b0c8 CTR: c0000000000ba3b0
REGS: c000003f7f9934b0 TRAP: 0700   Not tainted  (5.3.0-xive-nr-servers-5.3-gku+)
MSR:  9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 48228222  XER: 20040000
CFAR: c000000000131a50 IRQMASK: 0
GPR00: c00000000053b0c8 c000003f7f993740 c0000000015ec500 0000000000000057
GPR04: 0000000000000001 0000000000000000 000049fb98484262 0000000000001bcf
GPR08: 0000000000000007 0000000000000007 0000000000000001 9000000000001033
GPR12: 0000000000008000 c000003ffffeb800 0000000000000000 000000012f4ce5a1
GPR16: 000000012ef5a0c8 0000000000000000 000000012f113bb0 0000000000000000
GPR20: 000000012f45d918 c000003f863758b0 c000003f86375870 0000000000000006
GPR24: c000003f86375a30 0000000000000007 c0002039373d9020 c0000000014c4a48
GPR28: 0000000000000001 c000003fe62a4f6b c00020394b2e9fab c000003fe62a4ec0
NIP [c00000000053b0cc] remove_proc_entry+0x1ec/0x200
LR [c00000000053b0c8] remove_proc_entry+0x1e8/0x200
Call Trace:
[c000003f7f993740] [c00000000053b0c8] remove_proc_entry+0x1e8/0x200 (unreliable)
[c000003f7f9937e0] [c0000000001d3654] unregister_irq_proc+0x114/0x150
[c000003f7f993880] [c0000000001c6284] free_desc+0x54/0xb0
[c000003f7f9938c0] [c0000000001c65ec] irq_free_descs+0xac/0x100
[c000003f7f993910] [c0000000001d1ff8] irq_dispose_mapping+0x68/0x80
[c000003f7f993940] [c00800000d44e8a4] kvmppc_xive_attach_escalation+0x1fc/0x270 [kvm]
[c000003f7f9939d0] [c00800000d45013c] kvmppc_xive_connect_vcpu+0x424/0x620 [kvm]
[c000003f7f993ac0] [c00800000d444428] kvm_arch_vcpu_ioctl+0x260/0x448 [kvm]
[c000003f7f993b90] [c00800000d43593c] kvm_vcpu_ioctl+0x154/0x7c8 [kvm]
[c000003f7f993d00] [c0000000004840f0] do_vfs_ioctl+0xe0/0xc30
[c000003f7f993db0] [c000000000484d44] ksys_ioctl+0x104/0x120
[c000003f7f993e00] [c000000000484d88] sys_ioctl+0x28/0x80
[c000003f7f993e20] [c00000000000b278] system_call+0x5c/0x68
Instruction dump:
2c230000 41820008 3923ff78 e8e900a0 3c82ff69 3c62ff8d 7fa6eb78 7fc5f378
3884f080 3863b948 4bbf6925 60000000 <0fe00000> 4bffff7c fba10088 4bbf6e41
---[ end trace b925b67a74a1d8d1 ]---
BUG: Kernel NULL pointer dereference at 0x00000010
Faulting instruction address: 0xc00800000d44fc04
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in: kvm_hv kvm dm_mod vhost_net vhost tap xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter squashfs loop fuse i2c_dev sg ofpart ocxl powernv_flash at24 xts mtd uio_pdrv_genirq vmx_crypto opal_prd ipmi_powernv uio ipmi_devintf ipmi_msghandler ibmpowernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear sd_mod ast i2c_algo_bit drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci libata tg3 drm_panel_orientation_quirks [last unloaded: kvm]
CPU: 24 PID: 88176 Comm: qemu-system-ppc Tainted: G        W         5.3.0-xive-nr-servers-5.3-gku+ #38
NIP:  c00800000d44fc04 LR: c00800000d44fc00 CTR: c0000000001cd970
REGS: c000003f7f9938e0 TRAP: 0300   Tainted: G        W          (5.3.0-xive-nr-servers-5.3-gku+)
MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 24228882  XER: 20040000
CFAR: c0000000001cd9ac DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0
GPR00: c00800000d44fc00 c000003f7f993b70 c00800000d468300 0000000000000000
GPR04: 00000000000000c7 0000000000000000 0000000000000000 c000003ffacd06d8
GPR08: 0000000000000000 c000003ffacd0738 0000000000000000 fffffffffffffffd
GPR12: 0000000000000040 c000003ffffeb800 0000000000000000 000000012f4ce5a1
GPR16: 000000012ef5a0c8 0000000000000000 000000012f113bb0 0000000000000000
GPR20: 000000012f45d918 00007ffffe0d9a80 000000012f4f5df0 000000012ef8c9f8
GPR24: 0000000000000001 0000000000000000 c000003fe4501ed0 c000003f8b1d0000
GPR28: c0000033314689c0 c000003fe4501c00 c000003fe4501e70 c000003fe4501e90
NIP [c00800000d44fc04] kvmppc_xive_cleanup_vcpu+0xfc/0x210 [kvm]
LR [c00800000d44fc00] kvmppc_xive_cleanup_vcpu+0xf8/0x210 [kvm]
Call Trace:
[c000003f7f993b70] [c00800000d44fc00] kvmppc_xive_cleanup_vcpu+0xf8/0x210 [kvm] (unreliable)
[c000003f7f993bd0] [c00800000d450bd4] kvmppc_xive_release+0xdc/0x1b0 [kvm]
[c000003f7f993c30] [c00800000d436a98] kvm_device_release+0xb0/0x110 [kvm]
[c000003f7f993c70] [c00000000046730c] __fput+0xec/0x320
[c000003f7f993cd0] [c000000000164ae0] task_work_run+0x150/0x1c0
[c000003f7f993d30] [c000000000025034] do_notify_resume+0x304/0x440
[c000003f7f993e20] [c00000000000dcc4] ret_from_except_lite+0x70/0x74
Instruction dump:
3bff0008 7fbfd040 419e0054 847e0004 2fa30000 419effec e93d0000 8929203c
2f890000 419effb8 4800821d e8410018 <e9230010> e9490008 9b2a0039 7c0004ac
---[ end trace b925b67a74a1d8d2 ]---

Kernel panic - not syncing: Fatal exception

This affects both XIVE and XICS-on-XIVE devices since the beginning.

Check the VP id instead of the vCPU id when a new vCPU is connected.
The allocation of the XIVE CPU structure in kvmppc_xive_connect_vcpu()
is moved after the check to avoid the need for rollback.

Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-10-15 16:09:11 +11:00
Jordan Niethe
7fe4e1176d powerpc/kvm: Fix kvmppc_vcore->in_guest value in kvmhv_switch_to_host
kvmhv_switch_to_host() in arch/powerpc/kvm/book3s_hv_rmhandlers.S
needs to set kvmppc_vcore->in_guest to 0 to signal secondary CPUs to
continue. This happens after resetting the PCR. Before commit
13c7bb3c57 ("powerpc/64s: Set reserved PCR bits"), r0 would always
be 0 before it was stored to kvmppc_vcore->in_guest. However because
of this change in the commit:

          /* Reset PCR */
          ld      r0, VCORE_PCR(r5)
  -       cmpdi   r0, 0
  +       LOAD_REG_IMMEDIATE(r6, PCR_MASK)
  +       cmpld   r0, r6
          beq     18f
  -       li      r0, 0
  -       mtspr   SPRN_PCR, r0
  +       mtspr   SPRN_PCR, r6
   18:
          /* Signal secondary CPUs to continue */
          stb     r0,VCORE_IN_GUEST(r5)

We are no longer comparing r0 against 0 and loading it with 0 if it
contains something else. Hence when we store r0 to
kvmppc_vcore->in_guest, it might not be 0. This means that secondary
CPUs will not be signalled to continue. Those CPUs get stuck and
errors like the following are logged:

    KVM: CPU 1 seems to be stuck
    KVM: CPU 2 seems to be stuck
    KVM: CPU 3 seems to be stuck
    KVM: CPU 4 seems to be stuck
    KVM: CPU 5 seems to be stuck
    KVM: CPU 6 seems to be stuck
    KVM: CPU 7 seems to be stuck

This can be reproduced with:
    $ for i in `seq 1 7` ; do chcpu -d $i ; done ;
    $ taskset -c 0 qemu-system-ppc64 -smp 8,threads=8 \
       -M pseries,accel=kvm,kvm-type=HV -m 1G -nographic -vga none \
       -kernel vmlinux -initrd initrd.cpio.xz

Fix by making sure r0 is 0 before storing it to
kvmppc_vcore->in_guest.

Fixes: 13c7bb3c57 ("powerpc/64s: Set reserved PCR bits")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191004025317.19340-1-jniethe5@gmail.com
2019-10-09 17:16:59 +11:00
Linus Torvalds
b145b0eb20 ARM and x86 bugfixes of all kinds. The most visible one is that migrating
a nested hypervisor has always been busted on Broadwell and newer processors,
 and that has finally been fixed.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "ARM and x86 bugfixes of all kinds.

  The most visible one is that migrating a nested hypervisor has always
  been busted on Broadwell and newer processors, and that has finally
  been fixed"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (22 commits)
  KVM: x86: omit "impossible" pmu MSRs from MSR list
  KVM: nVMX: Fix consistency check on injected exception error code
  KVM: x86: omit absent pmu MSRs from MSR list
  selftests: kvm: Fix libkvm build error
  kvm: vmx: Limit guest PMCs to those supported on the host
  kvm: x86, powerpc: do not allow clearing largepages debugfs entry
  KVM: selftests: x86: clarify what is reported on KVM_GET_MSRS failure
  KVM: VMX: Set VMENTER_L1D_FLUSH_NOT_REQUIRED if !X86_BUG_L1TF
  selftests: kvm: add test for dirty logging inside nested guests
  KVM: x86: fix nested guest live migration with PML
  KVM: x86: assign two bits to track SPTE kinds
  KVM: x86: Expose XSAVEERPTR to the guest
  kvm: x86: Enumerate support for CLZERO instruction
  kvm: x86: Use AMD CPUID semantics for AMD vCPUs
  kvm: x86: Improve emulation of CPUID leaves 0BH and 1FH
  KVM: X86: Fix userspace set invalid CR4
  kvm: x86: Fix a spurious -E2BIG in __do_cpuid_func
  KVM: LAPIC: Loosen filter for adaptive tuning of lapic_timer_advance_ns
  KVM: arm/arm64: vgic: Use the appropriate TRACE_INCLUDE_PATH
  arm64: KVM: Kill hyp_alternate_select()
  ...
2019-10-04 11:17:51 -07:00
Paolo Bonzini
833b45de69 kvm: x86, powerpc: do not allow clearing largepages debugfs entry
The largepages debugfs entry is incremented/decremented as shadow
pages are created or destroyed.  Clearing it will result in an
underflow, which is harmless to KVM but ugly (and could be
misinterpreted by tools that use debugfs information), so make
this particular statistic read-only.

Cc: kvm-ppc@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-09-30 18:52:00 +02:00
Aneesh Kumar K.V
047e6575ae powerpc/mm: Fixup tlbie vs mtpidr/mtlpidr ordering issue on POWER9
On POWER9, under some circumstances, a broadcast TLB invalidation will
fail to invalidate the ERAT cache on some threads when there are
parallel mtpidr/mtlpidr happening on other threads of the same core.
This can cause stores to continue to go to a page after it's unmapped.

The workaround is to force an ERAT flush using PID=0 or LPID=0 tlbie
flush. This additional TLB flush will cause the ERAT cache
invalidation. Since we are using PID=0 or LPID=0, we don't get
filtered out by the TLB snoop filtering logic.

We need to still follow this up with another tlbie to take care of
store vs tlbie ordering issue explained in commit:
a5d4b5891c ("powerpc/mm: Fixup tlbie vs store ordering issue on
POWER9"). The presence of ERAT cache implies we can still get new
stores and they may miss store queue marking flush.

Cc: stable@vger.kernel.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-3-aneesh.kumar@linux.ibm.com
2019-09-24 20:58:55 +10:00
Aneesh Kumar K.V
09ce98cacd powerpc/book3s64/radix: Rename CPU_FTR_P9_TLBIE_BUG feature flag
Rename the #define to indicate this is related to store vs tlbie
ordering issue. In the next patch, we will be adding another feature
flag that is used to handles ERAT flush vs tlbie ordering issue.

Fixes: a5d4b5891c ("powerpc/mm: Fixup tlbie vs store ordering issue on POWER9")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-2-aneesh.kumar@linux.ibm.com
2019-09-24 20:58:47 +10:00
Michael Roth
3a83f677a6 KVM: PPC: Book3S HV: use smp_mb() when setting/clearing host_ipi flag
On a 2-socket Power9 system with 32 cores/128 threads (SMT4) and 1TB
of memory running the following guest configs:

  guest A:
    - 224GB of memory
    - 56 VCPUs (sockets=1,cores=28,threads=2), where:
      VCPUs 0-1 are pinned to CPUs 0-3,
      VCPUs 2-3 are pinned to CPUs 4-7,
      ...
      VCPUs 54-55 are pinned to CPUs 108-111

  guest B:
    - 4GB of memory
    - 4 VCPUs (sockets=1,cores=4,threads=1)

with the following workloads (with KSM and THP enabled in all):

  guest A:
    stress --cpu 40 --io 20 --vm 20 --vm-bytes 512M

  guest B:
    stress --cpu 4 --io 4 --vm 4 --vm-bytes 512M

  host:
    stress --cpu 4 --io 4 --vm 2 --vm-bytes 256M

the below soft-lockup traces were observed after an hour or so and
persisted until the host was reset (this was found to be reliably
reproducible for this configuration, for kernels 4.15, 4.18, 5.0,
and 5.3-rc5):

  [ 1253.183290] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1253.183319] rcu:     124-....: (5250 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=1941
  [ 1256.287426] watchdog: BUG: soft lockup - CPU#105 stuck for 23s! [CPU 52/KVM:19709]
  [ 1264.075773] watchdog: BUG: soft lockup - CPU#24 stuck for 23s! [worker:19913]
  [ 1264.079769] watchdog: BUG: soft lockup - CPU#31 stuck for 23s! [worker:20331]
  [ 1264.095770] watchdog: BUG: soft lockup - CPU#45 stuck for 23s! [worker:20338]
  [ 1264.131773] watchdog: BUG: soft lockup - CPU#64 stuck for 23s! [avocado:19525]
  [ 1280.408480] watchdog: BUG: soft lockup - CPU#124 stuck for 22s! [ksmd:791]
  [ 1316.198012] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1316.198032] rcu:     124-....: (21003 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=8243
  [ 1340.411024] watchdog: BUG: soft lockup - CPU#124 stuck for 22s! [ksmd:791]
  [ 1379.212609] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1379.212629] rcu:     124-....: (36756 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=14714
  [ 1404.413615] watchdog: BUG: soft lockup - CPU#124 stuck for 22s! [ksmd:791]
  [ 1442.227095] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1442.227115] rcu:     124-....: (52509 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=21403
  [ 1455.111787] INFO: task worker:19907 blocked for more than 120 seconds.
  [ 1455.111822]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.111833] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.111884] INFO: task worker:19908 blocked for more than 120 seconds.
  [ 1455.111905]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.111925] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.111966] INFO: task worker:20328 blocked for more than 120 seconds.
  [ 1455.111986]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.111998] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112048] INFO: task worker:20330 blocked for more than 120 seconds.
  [ 1455.112068]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112097] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112138] INFO: task worker:20332 blocked for more than 120 seconds.
  [ 1455.112159]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112179] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112210] INFO: task worker:20333 blocked for more than 120 seconds.
  [ 1455.112231]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112242] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112282] INFO: task worker:20335 blocked for more than 120 seconds.
  [ 1455.112303]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112332] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112372] INFO: task worker:20336 blocked for more than 120 seconds.
  [ 1455.112392]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1

CPUs 45, 24, and 124 are stuck on spin locks, likely held by
CPUs 105 and 31.

CPUs 105 and 31 are stuck in smp_call_function_many(), waiting on
target CPU 42. For instance:

  # CPU 105 registers (via xmon)
  R00 = c00000000020b20c   R16 = 00007d1bcd800000
  R01 = c00000363eaa7970   R17 = 0000000000000001
  R02 = c0000000019b3a00   R18 = 000000000000006b
  R03 = 000000000000002a   R19 = 00007d537d7aecf0
  R04 = 000000000000002a   R20 = 60000000000000e0
  R05 = 000000000000002a   R21 = 0801000000000080
  R06 = c0002073fb0caa08   R22 = 0000000000000d60
  R07 = c0000000019ddd78   R23 = 0000000000000001
  R08 = 000000000000002a   R24 = c00000000147a700
  R09 = 0000000000000001   R25 = c0002073fb0ca908
  R10 = c000008ffeb4e660   R26 = 0000000000000000
  R11 = c0002073fb0ca900   R27 = c0000000019e2464
  R12 = c000000000050790   R28 = c0000000000812b0
  R13 = c000207fff623e00   R29 = c0002073fb0ca808
  R14 = 00007d1bbee00000   R30 = c0002073fb0ca800
  R15 = 00007d1bcd600000   R31 = 0000000000000800
  pc  = c00000000020b260 smp_call_function_many+0x3d0/0x460
  cfar= c00000000020b270 smp_call_function_many+0x3e0/0x460
  lr  = c00000000020b20c smp_call_function_many+0x37c/0x460
  msr = 900000010288b033   cr  = 44024824
  ctr = c000000000050790   xer = 0000000000000000   trap =  100

CPU 42 is running normally, doing VCPU work:

  # CPU 42 stack trace (via xmon)
  [link register   ] c00800001be17188 kvmppc_book3s_radix_page_fault+0x90/0x2b0 [kvm_hv]
  [c000008ed3343820] c000008ed3343850 (unreliable)
  [c000008ed33438d0] c00800001be11b6c kvmppc_book3s_hv_page_fault+0x264/0xe30 [kvm_hv]
  [c000008ed33439d0] c00800001be0d7b4 kvmppc_vcpu_run_hv+0x8dc/0xb50 [kvm_hv]
  [c000008ed3343ae0] c00800001c10891c kvmppc_vcpu_run+0x34/0x48 [kvm]
  [c000008ed3343b00] c00800001c10475c kvm_arch_vcpu_ioctl_run+0x244/0x420 [kvm]
  [c000008ed3343b90] c00800001c0f5a78 kvm_vcpu_ioctl+0x470/0x7c8 [kvm]
  [c000008ed3343d00] c000000000475450 do_vfs_ioctl+0xe0/0xc70
  [c000008ed3343db0] c0000000004760e4 ksys_ioctl+0x104/0x120
  [c000008ed3343e00] c000000000476128 sys_ioctl+0x28/0x80
  [c000008ed3343e20] c00000000000b388 system_call+0x5c/0x70
  --- Exception: c00 (System Call) at 00007d545cfd7694
  SP (7d53ff7edf50) is in userspace

It was subsequently found that ipi_message[PPC_MSG_CALL_FUNCTION]
was set for CPU 42 by at least 1 of the CPUs waiting in
smp_call_function_many(), but somehow the corresponding
call_single_queue entries were never processed by CPU 42, causing the
callers to spin in csd_lock_wait() indefinitely.

Nick Piggin suggested something similar to the following sequence as
a possible explanation (interleaving of CALL_FUNCTION/RESCHEDULE
IPI messages seems to be most common, but any mix of CALL_FUNCTION and
!CALL_FUNCTION messages could trigger it):

    CPU
      X: smp_muxed_ipi_set_message():
      X:   smp_mb()
      X:   message[RESCHEDULE] = 1
      X: doorbell_global_ipi(42):
      X:   kvmppc_set_host_ipi(42, 1)
      X:   ppc_msgsnd_sync()/smp_mb()
      X:   ppc_msgsnd() -> 42
     42: doorbell_exception(): // from CPU X
     42:   ppc_msgsync()
    105: smp_muxed_ipi_set_message():
    105:   smb_mb()
         // STORE DEFERRED DUE TO RE-ORDERING
  --105:   message[CALL_FUNCTION] = 1
  | 105: doorbell_global_ipi(42):
  | 105:   kvmppc_set_host_ipi(42, 1)
  |  42:   kvmppc_set_host_ipi(42, 0)
  |  42: smp_ipi_demux_relaxed()
  |  42: // returns to executing guest
  |      // RE-ORDERED STORE COMPLETES
  ->105:   message[CALL_FUNCTION] = 1
    105:   ppc_msgsnd_sync()/smp_mb()
    105:   ppc_msgsnd() -> 42
     42: local_paca->kvm_hstate.host_ipi == 0 // IPI ignored
    105: // hangs waiting on 42 to process messages/call_single_queue

This can be prevented with an smp_mb() at the beginning of
kvmppc_set_host_ipi(), such that stores to message[<type>] (or other
state indicated by the host_ipi flag) are ordered vs. the store to
to host_ipi.

However, doing so might still allow for the following scenario (not
yet observed):

    CPU
      X: smp_muxed_ipi_set_message():
      X:   smp_mb()
      X:   message[RESCHEDULE] = 1
      X: doorbell_global_ipi(42):
      X:   kvmppc_set_host_ipi(42, 1)
      X:   ppc_msgsnd_sync()/smp_mb()
      X:   ppc_msgsnd() -> 42
     42: doorbell_exception(): // from CPU X
     42:   ppc_msgsync()
         // STORE DEFERRED DUE TO RE-ORDERING
  -- 42:   kvmppc_set_host_ipi(42, 0)
  |  42: smp_ipi_demux_relaxed()
  | 105: smp_muxed_ipi_set_message():
  | 105:   smb_mb()
  | 105:   message[CALL_FUNCTION] = 1
  | 105: doorbell_global_ipi(42):
  | 105:   kvmppc_set_host_ipi(42, 1)
  |      // RE-ORDERED STORE COMPLETES
  -> 42:   kvmppc_set_host_ipi(42, 0)
     42: // returns to executing guest
    105:   ppc_msgsnd_sync()/smp_mb()
    105:   ppc_msgsnd() -> 42
     42: local_paca->kvm_hstate.host_ipi == 0 // IPI ignored
    105: // hangs waiting on 42 to process messages/call_single_queue

Fixing this scenario would require an smp_mb() *after* clearing
host_ipi flag in kvmppc_set_host_ipi() to order the store vs.
subsequent processing of IPI messages.

To handle both cases, this patch splits kvmppc_set_host_ipi() into
separate set/clear functions, where we execute smp_mb() prior to
setting host_ipi flag, and after clearing host_ipi flag. These
functions pair with each other to synchronize the sender and receiver
sides.

With that change in place the above workload ran for 20 hours without
triggering any lock-ups.

Fixes: 755563bc79 ("powerpc/powernv: Fixes for hypervisor doorbell handling") # v4.0
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190911223155.16045-1-mdroth@linux.vnet.ibm.com
2019-09-24 12:46:26 +10:00
Jordan Niethe
13c7bb3c57 powerpc/64s: Set reserved PCR bits
Currently the reserved bits of the Processor Compatibility
Register (PCR) are cleared as per the Programming Note in Section
1.3.3 of version 3.0B of the Power ISA. This causes all new
architecture features to be made available when running on newer
processors with new architecture features added to the PCR as bits
must be set to disable a given feature.

For example to disable new features added as part of Version 2.07 of
the ISA the corresponding bit in the PCR needs to be set.

As new processor features generally require explicit kernel support
they should be disabled until such support is implemented. Therefore
kernels should set all unknown/reserved bits in the PCR such that any
new architecture features which the kernel does not currently know
about get disabled.

An update is planned to the ISA to clarify that the PCR is an
exception to the Programming Note on reserved bits in Section 1.3.3.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190917004605.22471-2-alistair@popple.id.au
2019-09-21 08:36:53 +10:00
Linus Torvalds
45824fc0da powerpc updates for 5.4
- Initial support for running on a system with an Ultravisor, which is software
    that runs below the hypervisor and protects guests against some attacks by
    the hypervisor.
 
  - Support for building the kernel to run as a "Secure Virtual Machine", ie. as
    a guest capable of running on a system with an Ultravisor.
 
  - Some changes to our DMA code on bare metal, to allow devices with medium
    sized DMA masks (> 32 && < 59 bits) to use more than 2GB of DMA space.
 
  - Support for firmware assisted crash dumps on bare metal (powernv).
 
  - Two series fixing bugs in and refactoring our PCI EEH code.
 
  - A large series refactoring our exception entry code to use gas macros, both
    to make it more readable and also enable some future optimisations.
 
 As well as many cleanups and other minor features & fixups.
 
 Thanks to:
   Adam Zerella, Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh
   Kumar K.V, Anju T Sudhakar, Anshuman Khandual, Balbir Singh, Benjamin
   Herrenschmidt, Cédric Le Goater, Christophe JAILLET, Christophe Leroy,
   Christopher M. Riedl, Christoph Hellwig, Claudio Carvalho, Daniel Axtens,
   David Gibson, David Hildenbrand, Desnes A. Nunes do Rosario, Ganesh Goudar,
   Gautham R. Shenoy, Greg Kurz, Guerney Hunt, Gustavo Romero, Halil Pasic, Hari
   Bathini, Joakim Tjernlund, Jonathan Neuschafer, Jordan Niethe, Leonardo Bras,
   Lianbo Jiang, Madhavan Srinivasan, Mahesh Salgaonkar, Mahesh Salgaonkar,
   Masahiro Yamada, Maxiwell S. Garcia, Michael Anderson, Nathan Chancellor,
   Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Qian Cai, Ram
   Pai, Ravi Bangoria, Reza Arbab, Ryan Grimm, Sam Bobroff, Santosh Sivaraj,
   Segher Boessenkool, Sukadev Bhattiprolu, Thiago Bauermann, Thiago Jung
   Bauermann, Thomas Gleixner, Tom Lendacky, Vasant Hegde.
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Merge tag 'powerpc-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "This is a bit late, partly due to me travelling, and partly due to a
  power outage knocking out some of my test systems *while* I was
  travelling.

   - Initial support for running on a system with an Ultravisor, which
     is software that runs below the hypervisor and protects guests
     against some attacks by the hypervisor.

   - Support for building the kernel to run as a "Secure Virtual
     Machine", ie. as a guest capable of running on a system with an
     Ultravisor.

   - Some changes to our DMA code on bare metal, to allow devices with
     medium sized DMA masks (> 32 && < 59 bits) to use more than 2GB of
     DMA space.

   - Support for firmware assisted crash dumps on bare metal (powernv).

   - Two series fixing bugs in and refactoring our PCI EEH code.

   - A large series refactoring our exception entry code to use gas
     macros, both to make it more readable and also enable some future
     optimisations.

  As well as many cleanups and other minor features & fixups.

  Thanks to: Adam Zerella, Alexey Kardashevskiy, Alistair Popple, Andrew
  Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Anshuman Khandual,
  Balbir Singh, Benjamin Herrenschmidt, Cédric Le Goater, Christophe
  JAILLET, Christophe Leroy, Christopher M. Riedl, Christoph Hellwig,
  Claudio Carvalho, Daniel Axtens, David Gibson, David Hildenbrand,
  Desnes A. Nunes do Rosario, Ganesh Goudar, Gautham R. Shenoy, Greg
  Kurz, Guerney Hunt, Gustavo Romero, Halil Pasic, Hari Bathini, Joakim
  Tjernlund, Jonathan Neuschafer, Jordan Niethe, Leonardo Bras, Lianbo
  Jiang, Madhavan Srinivasan, Mahesh Salgaonkar, Mahesh Salgaonkar,
  Masahiro Yamada, Maxiwell S. Garcia, Michael Anderson, Nathan
  Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Oliver
  O'Halloran, Qian Cai, Ram Pai, Ravi Bangoria, Reza Arbab, Ryan Grimm,
  Sam Bobroff, Santosh Sivaraj, Segher Boessenkool, Sukadev Bhattiprolu,
  Thiago Bauermann, Thiago Jung Bauermann, Thomas Gleixner, Tom
  Lendacky, Vasant Hegde"

* tag 'powerpc-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (264 commits)
  powerpc/mm/mce: Keep irqs disabled during lockless page table walk
  powerpc: Use ftrace_graph_ret_addr() when unwinding
  powerpc/ftrace: Enable HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
  ftrace: Look up the address of return_to_handler() using helpers
  powerpc: dump kernel log before carrying out fadump or kdump
  docs: powerpc: Add missing documentation reference
  powerpc/xmon: Fix output of XIVE IPI
  powerpc/xmon: Improve output of XIVE interrupts
  powerpc/mm/radix: remove useless kernel messages
  powerpc/fadump: support holes in kernel boot memory area
  powerpc/fadump: remove RMA_START and RMA_END macros
  powerpc/fadump: update documentation about option to release opalcore
  powerpc/fadump: consider f/w load area
  powerpc/opalcore: provide an option to invalidate /sys/firmware/opal/core file
  powerpc/opalcore: export /sys/firmware/opal/core for analysing opal crashes
  powerpc/fadump: update documentation about CONFIG_PRESERVE_FA_DUMP
  powerpc/fadump: add support to preserve crash data on FADUMP disabled kernel
  powerpc/fadump: improve how crashed kernel's memory is reserved
  powerpc/fadump: consider reserved ranges while releasing memory
  powerpc/fadump: make crash memory ranges array allocation generic
  ...
2019-09-20 11:48:06 -07:00
Linus Torvalds
fe38bd6862 * s390: ioctl hardening, selftests
* ARM: ITS translation cache; support for 512 vCPUs, various cleanups
 and bugfixes
 
 * PPC: various minor fixes and preparation
 
 * x86: bugfixes all over the place (posted interrupts, SVM, emulation
 corner cases, blocked INIT), some IPI optimizations
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "s390:
   - ioctl hardening
   - selftests

  ARM:
   - ITS translation cache
   - support for 512 vCPUs
   - various cleanups and bugfixes

  PPC:
   - various minor fixes and preparation

  x86:
   - bugfixes all over the place (posted interrupts, SVM, emulation
     corner cases, blocked INIT)
   - some IPI optimizations"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (75 commits)
  KVM: X86: Use IPI shorthands in kvm guest when support
  KVM: x86: Fix INIT signal handling in various CPU states
  KVM: VMX: Introduce exit reason for receiving INIT signal on guest-mode
  KVM: VMX: Stop the preemption timer during vCPU reset
  KVM: LAPIC: Micro optimize IPI latency
  kvm: Nested KVM MMUs need PAE root too
  KVM: x86: set ctxt->have_exception in x86_decode_insn()
  KVM: x86: always stop emulation on page fault
  KVM: nVMX: trace nested VM-Enter failures detected by H/W
  KVM: nVMX: add tracepoint for failed nested VM-Enter
  x86: KVM: svm: Fix a check in nested_svm_vmrun()
  KVM: x86: Return to userspace with internal error on unexpected exit reason
  KVM: x86: Add kvm_emulate_{rd,wr}msr() to consolidate VXM/SVM code
  KVM: x86: Refactor up kvm_{g,s}et_msr() to simplify callers
  doc: kvm: Fix return description of KVM_SET_MSRS
  KVM: X86: Tune PLE Window tracepoint
  KVM: VMX: Change ple_window type to unsigned int
  KVM: X86: Remove tailing newline for tracepoints
  KVM: X86: Trace vcpu_id for vmexit
  KVM: x86: Manually calculate reserved bits when loading PDPTRS
  ...
2019-09-18 09:49:13 -07:00
Paolo Bonzini
8146856b0a PPC KVM update for 5.4
- Some prep for extending the uses of the rmap array
 - Various minor fixes
 - Commits from the powerpc topic/ppc-kvm branch, which fix a problem
   with interrupts arriving after free_irq, causing host hangs and crashes.
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Merge tag 'kvm-ppc-next-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD

PPC KVM update for 5.4

- Some prep for extending the uses of the rmap array
- Various minor fixes
- Commits from the powerpc topic/ppc-kvm branch, which fix a problem
  with interrupts arriving after free_irq, causing host hangs and crashes.
2019-09-10 16:51:17 +02:00
Nicholas Piggin
2275d7b575 powerpc/64s/radix: introduce options to disable use of the tlbie instruction
Introduce two options to control the use of the tlbie instruction. A
boot time option which completely disables the kernel using the
instruction, this is currently incompatible with HASH MMU, KVM, and
coherent accelerators.

And a debugfs option can be switched at runtime and avoids using tlbie
for invalidating CPU TLBs for normal process and kernel address
mappings. Coherent accelerators are still managed with tlbie, as will
KVM partition scope translations.

Cross-CPU TLB flushing is implemented with IPIs and tlbiel. This is a
basic implementation which does not attempt to make any optimisation
beyond the tlbie implementation.

This is useful for performance testing among other things. For example
in certain situations on large systems, using IPIs may be faster than
tlbie as they can be directed rather than broadcast. Later we may also
take advantage of the IPIs to do more interesting things such as trim
the mm cpumask more aggressively.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190902152931.17840-7-npiggin@gmail.com
2019-09-05 14:22:41 +10:00
Nicholas Piggin
fd13daea5f powerpc/64s: make mmu_partition_table_set_entry TLB flush optional
No functional change.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190902152931.17840-4-npiggin@gmail.com
2019-09-05 14:22:40 +10:00
Nicholas Piggin
99161de3a2 powerpc/64s/radix: tidy up TLB flushing code
There should be no functional changes.

- Use calls to existing radix_tlb.c functions in flush_partition.

- Rename radix__flush_tlb_lpid to radix__flush_all_lpid and similar,
  because they flush everything, matching flush_all_mm rather than
  flush_tlb_mm for the lpid.

- Remove some unused radix_tlb.c flush primitives.

Signed-off: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190902152931.17840-3-npiggin@gmail.com
2019-09-05 14:22:40 +10:00
Michael Ellerman
9044adca78 Merge branch 'topic/ppc-kvm' into next
Merge our ppc-kvm topic branch to bring in the Ultravisor support
patches.
2019-08-30 09:52:57 +10:00
Sukadev Bhattiprolu
6c85b7bc63 powerpc/kvm: Use UV_RETURN ucall to return to ultravisor
When an SVM makes an hypercall or incurs some other exception, the
Ultravisor usually forwards (a.k.a. reflects) the exceptions to the
Hypervisor. After processing the exception, Hypervisor uses the
UV_RETURN ultracall to return control back to the SVM.

The expected register state on entry to this ultracall is:

* Non-volatile registers are restored to their original values.
* If returning from an hypercall, register R0 contains the return value
  (unlike other ultracalls) and, registers R4 through R12 contain any
  output values of the hypercall.
* R3 contains the ultracall number, i.e UV_RETURN.
* If returning with a synthesized interrupt, R2 contains the
  synthesized interrupt number.

Thanks to input from Paul Mackerras, Ram Pai and Mike Anderson.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190822034838.27876-8-cclaudio@linux.ibm.com
2019-08-30 09:40:16 +10:00
Alexey Kardashevskiy
01b7d128b5 KVM: PPC: Book3S: Invalidate multiple TCEs at once
Invalidating a TCE cache entry for each updated TCE is quite expensive.
This makes use of the new iommu_table_ops::xchg_no_kill()/tce_kill()
callbacks to bring down the time spent in mapping a huge guest DMA window;
roughly 20s to 10s for each guest's 100GB of DMA space.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190829085252.72370-3-aik@ozlabs.ru
2019-08-30 09:40:14 +10:00
Alexey Kardashevskiy
4f916593be KVM: PPC: Book3S: Fix incorrect guest-to-user-translation error handling
H_PUT_TCE_INDIRECT handlers receive a page with up to 512 TCEs from
a guest. Although we verify correctness of TCEs before we do anything
with the existing tables, there is a small window when a check in
kvmppc_tce_validate might pass and right after that the guest alters
the page with TCEs which can cause early exit from the handler and
leave srcu_read_lock(&vcpu->kvm->srcu) (virtual mode) or lock_rmap(rmap)
(real mode) locked.

This fixes the bug by jumping to the common exit code with an appropriate
unlock.

Fixes: 121f80ba68 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190826045520.92153-1-aik@ozlabs.ru
2019-08-30 09:40:14 +10:00
Radim Krčmář
c91ff72142 Merge tag 'kvm-ppc-fixes-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
KVM/PPC fix for 5.3

- Fix bug which could leave locks locked in the host on return
  to a guest.
2019-08-27 16:02:48 +02:00
Paul Mackerras
ff42df49e7 KVM: PPC: Book3S HV: Don't lose pending doorbell request on migration on P9
On POWER9, when userspace reads the value of the DPDES register on a
vCPU, it is possible for 0 to be returned although there is a doorbell
interrupt pending for the vCPU.  This can lead to a doorbell interrupt
being lost across migration.  If the guest kernel uses doorbell
interrupts for IPIs, then it could malfunction because of the lost
interrupt.

This happens because a newly-generated doorbell interrupt is signalled
by setting vcpu->arch.doorbell_request to 1; the DPDES value in
vcpu->arch.vcore->dpdes is not updated, because it can only be updated
when holding the vcpu mutex, in order to avoid races.

To fix this, we OR in vcpu->arch.doorbell_request when reading the
DPDES value.

Cc: stable@vger.kernel.org # v4.13+
Fixes: 579006944e ("KVM: PPC: Book3S HV: Virtualize doorbell facility on POWER9")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
2019-08-27 14:08:22 +10:00
Paul Mackerras
d28eafc5a6 KVM: PPC: Book3S HV: Check for MMU ready on piggybacked virtual cores
When we are running multiple vcores on the same physical core, they
could be from different VMs and so it is possible that one of the
VMs could have its arch.mmu_ready flag cleared (for example by a
concurrent HPT resize) when we go to run it on a physical core.
We currently check the arch.mmu_ready flag for the primary vcore
but not the flags for the other vcores that will be run alongside
it.  This adds that check, and also a check when we select the
secondary vcores from the preempted vcores list.

Cc: stable@vger.kernel.org # v4.14+
Fixes: 38c53af853 ("KVM: PPC: Book3S HV: Fix exclusion between HPT resizing and other HPT updates")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-08-27 14:08:10 +10:00