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KVM: SVM: Emulate SYSENTER RIP/RSP behavior for all Intel compat vCPUs

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Emulate bits 63:32 of the SYSENTER_R{I,S}P MSRs for all vCPUs that are
compatible with Intel's architecture, not just strictly vCPUs that have
vendor==Intel.  The behavior of bits 63:32 is architecturally defined in
the SDM, i.e. not some uarch specific quirk of Intel CPUs.

Link: https://lore.kernel.org/r/20240405235603.1173076-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2024-04-05 16:56:00 -07:00
parent d99e4cb2ae
commit dc2b8b2b52
2 changed files with 7 additions and 15 deletions
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8
arch/x86/kvm/cpuid.h
View File

@ -112,14 +112,6 @@ static inline bool guest_cpuid_is_amd_or_hygon(struct kvm_vcpu *vcpu)
is_guest_vendor_hygon(best->ebx, best->ecx, best->edx));
}
static inline bool guest_cpuid_is_intel(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0);
return best && is_guest_vendor_intel(best->ebx, best->ecx, best->edx);
}
static inline bool guest_cpuid_is_amd_compatible(struct kvm_vcpu *vcpu)
{
return vcpu->arch.is_amd_compatible;

14
arch/x86/kvm/svm/svm.c
View File

@ -1196,7 +1196,7 @@ static inline void init_vmcb_after_set_cpuid(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
if (guest_cpuid_is_intel(vcpu)) {
if (guest_cpuid_is_intel_compatible(vcpu)) {
/*
* We must intercept SYSENTER_EIP and SYSENTER_ESP
* accesses because the processor only stores 32 bits.
@ -2855,12 +2855,12 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
break;
case MSR_IA32_SYSENTER_EIP:
msr_info->data = (u32)svm->vmcb01.ptr->save.sysenter_eip;
if (guest_cpuid_is_intel(vcpu))
if (guest_cpuid_is_intel_compatible(vcpu))
msr_info->data |= (u64)svm->sysenter_eip_hi << 32;
break;
case MSR_IA32_SYSENTER_ESP:
msr_info->data = svm->vmcb01.ptr->save.sysenter_esp;
if (guest_cpuid_is_intel(vcpu))
if (guest_cpuid_is_intel_compatible(vcpu))
msr_info->data |= (u64)svm->sysenter_esp_hi << 32;
break;
case MSR_TSC_AUX:
@ -3083,11 +3083,11 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
* 32 bit part of these msrs to support Intel's
* implementation of SYSENTER/SYSEXIT.
*/
svm->sysenter_eip_hi = guest_cpuid_is_intel(vcpu) ? (data >> 32) : 0;
svm->sysenter_eip_hi = guest_cpuid_is_intel_compatible(vcpu) ? (data >> 32) : 0;
break;
case MSR_IA32_SYSENTER_ESP:
svm->vmcb01.ptr->save.sysenter_esp = (u32)data;
svm->sysenter_esp_hi = guest_cpuid_is_intel(vcpu) ? (data >> 32) : 0;
svm->sysenter_esp_hi = guest_cpuid_is_intel_compatible(vcpu) ? (data >> 32) : 0;
break;
case MSR_TSC_AUX:
/*
@ -4337,11 +4337,11 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_LBRV);
/*
* Intercept VMLOAD if the vCPU mode is Intel in order to emulate that
* Intercept VMLOAD if the vCPU model is Intel in order to emulate that
* VMLOAD drops bits 63:32 of SYSENTER (ignoring the fact that exposing
* SVM on Intel is bonkers and extremely unlikely to work).
*/
if (!guest_cpuid_is_intel(vcpu))
if (!guest_cpuid_is_intel_compatible(vcpu))
kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_PAUSEFILTER);