linux-brain/arch
Sean Christopherson 06dad664d4 KVM: nVMX: Unconditionally clear nested.pi_pending on nested VM-Enter
commit f7782bb8d818d8f47c26b22079db10599922787a upstream.

Clear nested.pi_pending on nested VM-Enter even if L2 will run without
posted interrupts enabled.  If nested.pi_pending is left set from a
previous L2, vmx_complete_nested_posted_interrupt() will pick up the
stale flag and exit to userspace with an "internal emulation error" due
the new L2 not having a valid nested.pi_desc.

Arguably, vmx_complete_nested_posted_interrupt() should first check for
posted interrupts being enabled, but it's also completely reasonable that
KVM wouldn't screw up a fundamental flag.  Not to mention that the mere
existence of nested.pi_pending is a long-standing bug as KVM shouldn't
move the posted interrupt out of the IRR until it's actually processed,
e.g. KVM effectively drops an interrupt when it performs a nested VM-Exit
with a "pending" posted interrupt.  Fixing the mess is a future problem.

Prior to vmx_complete_nested_posted_interrupt() interpreting a null PI
descriptor as an error, this was a benign bug as the null PI descriptor
effectively served as a check on PI not being enabled.  Even then, the
new flow did not become problematic until KVM started checking the result
of kvm_check_nested_events().

Fixes: 705699a139 ("KVM: nVMX: Enable nested posted interrupt processing")
Fixes: 966eefb89657 ("KVM: nVMX: Disable vmcs02 posted interrupts if vmcs12 PID isn't mappable")
Fixes: 47d3530f86c0 ("KVM: x86: Exit to userspace when kvm_check_nested_events fails")
Cc: stable@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210810144526.2662272-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-15 09:47:41 +02:00
..
alpha alpha: Send stop IPI to send to online CPUs 2021-08-12 13:21:05 +02:00
arc ARC: wireup clone3 syscall 2021-09-12 08:56:40 +02:00
arm bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-09-15 09:47:38 +02:00
arm64 bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-09-15 09:47:38 +02:00
c6x mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
csky csky: change a Kconfig symbol name to fix e1000 build error 2021-04-28 13:19:16 +02:00
h8300 h8300: fix PREEMPTION build, TI_PRE_COUNT undefined 2021-02-17 10:35:18 +01:00
hexagon hexagon: use common DISCARDS macro 2021-07-20 16:10:50 +02:00
ia64 ia64: mca_drv: fix incorrect array size calculation 2021-07-14 16:53:19 +02:00
m68k m68k: emu: Fix invalid free in nfeth_cleanup() 2021-09-15 09:47:28 +02:00
microblaze microblaze: Prevent the overflow of the start 2020-02-24 08:37:02 +01:00
mips bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-09-15 09:47:38 +02:00
nds32 nds32: fix up stack guard gap 2021-07-28 13:31:01 +02:00
nios2 nios2 update for v5.4-rc1 2019-09-27 13:02:19 -07:00
openrisc openrisc: Define memory barrier mb 2021-06-03 08:59:11 +02:00
parisc Revert "parisc: Add assembly implementations for memset, strlen, strcpy, strncpy and strcat" 2021-09-03 10:08:16 +02:00
powerpc bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-09-15 09:47:38 +02:00
riscv bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-09-15 09:47:38 +02:00
s390 KVM: s390: index kvm->arch.idle_mask by vcpu_idx 2021-09-15 09:47:40 +02:00
sh sh: dma: fix kconfig dependency for G2_DMA 2021-01-27 11:47:52 +01:00
sparc bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-09-15 09:47:38 +02:00
um um: fix error return code in winch_tramp() 2021-07-20 16:10:49 +02:00
unicore32 mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
x86 KVM: nVMX: Unconditionally clear nested.pi_pending on nested VM-Enter 2021-09-15 09:47:41 +02:00
xtensa xtensa: fix kconfig unmet dependency warning for HAVE_FUTEX_CMPXCHG 2021-09-12 08:56:39 +02:00
.gitignore
Kconfig Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" 2020-12-30 11:51:47 +01:00