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KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES

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commit 28c1c9fabf upstream.

Intel processors use MSR_IA32_ARCH_CAPABILITIES MSR to indicate RDCL_NO
(bit 0) and IBRS_ALL (bit 1). This is a read-only MSR. By default the
contents will come directly from the hardware, but user-space can still
override it.

[dwmw2: The bit in kvm_cpuid_7_0_edx_x86_features can be unconditional]

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: kvm@vger.kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Link: https://lkml.kernel.org/r/1517522386-18410-4-git-send-email-karahmed@amazon.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
KarimAllah Ahmed 2018-02-01 22:59:44 +01:00 committed by Greg Kroah-Hartman
parent 4b3870c343
commit 337c26f50a
4 changed files with 33 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/x86/kvm/cpuid.c
View File

@ -362,6 +362,10 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
const u32 kvm_supported_word10_x86_features =
F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
/* cpuid 7.0.edx*/
const u32 kvm_cpuid_7_0_edx_x86_features =
F(ARCH_CAPABILITIES);
/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();
@ -439,11 +443,14 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
cpuid_mask(&entry->ebx, 9);
// TSC_ADJUST is emulated
entry->ebx |= F(TSC_ADJUST);
} else
entry->edx &= kvm_cpuid_7_0_edx_x86_features;
cpuid_mask(&entry->edx, CPUID_7_EDX);
} else {
entry->ebx = 0;
entry->edx = 0;
}
entry->eax = 0;
entry->ecx = 0;
entry->edx = 0;
break;
}
case 9:

8
arch/x86/kvm/cpuid.h
View File

@ -170,6 +170,14 @@ static inline bool guest_cpuid_has_ibpb(struct kvm_vcpu *vcpu)
return best && (best->edx & bit(X86_FEATURE_SPEC_CTRL));
}
static inline bool guest_cpuid_has_arch_capabilities(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 7, 0);
return best && (best->edx & bit(X86_FEATURE_ARCH_CAPABILITIES));
}
/*
* NRIPS is provided through cpuidfn 0x8000000a.edx bit 3

15
arch/x86/kvm/vmx.c
View File

@ -545,6 +545,8 @@ struct vcpu_vmx {
u64 msr_guest_kernel_gs_base;
#endif
u64 arch_capabilities;
u32 vm_entry_controls_shadow;
u32 vm_exit_controls_shadow;
/*
@ -2832,6 +2834,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_TSC:
msr_info->data = guest_read_tsc(vcpu);
break;
case MSR_IA32_ARCH_CAPABILITIES:
if (!msr_info->host_initiated &&
!guest_cpuid_has_arch_capabilities(vcpu))
return 1;
msr_info->data = to_vmx(vcpu)->arch_capabilities;
break;
case MSR_IA32_SYSENTER_CS:
msr_info->data = vmcs_read32(GUEST_SYSENTER_CS);
break;
@ -2958,6 +2966,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
vmx_disable_intercept_for_msr(vmx->vmcs01.msr_bitmap, MSR_IA32_PRED_CMD,
MSR_TYPE_W);
break;
case MSR_IA32_ARCH_CAPABILITIES:
if (!msr_info->host_initiated)
return 1;
vmx->arch_capabilities = data;
break;
case MSR_IA32_CR_PAT:
if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
@ -5002,6 +5015,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
++vmx->nmsrs;
}
if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
rdmsrl(MSR_IA32_ARCH_CAPABILITIES, vmx->arch_capabilities);
vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl);

1
arch/x86/kvm/x86.c
View File

@ -961,6 +961,7 @@ static u32 msrs_to_save[] = {
#endif
MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
MSR_IA32_ARCH_CAPABILITIES
};
static unsigned num_msrs_to_save;