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KVM: x86: Drop special XSAVE handling from guest_cpuid_has()

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Now that KVM prevents setting host-reserved CR4 bits, drop the dedicated
XSAVE check in guest_cpuid_has() in favor of open coding similar checks
in the SVM/VMX XSAVES enabling flows.

Note, checking boot_cpu_has(X86_FEATURE_XSAVE) in the XSAVES flows is
technically redundant with respect to the CR4 reserved bit checks, e.g.
XSAVES #UDs if CR4.OSXSAVE=0 and arch.xsaves_enabled is consumed if and
only if CR4.OXSAVE=1 in guest.  Keep (add?) the explicit boot_cpu_has()
checks to help document KVM's usage of arch.xsaves_enabled.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2019-12-10 14:44:15 -08:00
committed by Paolo Bonzini
parent f1cdecf580
commit 96be4e069c
3 changed files with 2 additions and 4 deletions
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4
arch/x86/kvm/cpuid.h
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@@ -93,10 +93,6 @@ static __always_inline bool guest_cpuid_has(struct kvm_vcpu *vcpu, unsigned x86_
{
int *reg;
if (x86_feature == X86_FEATURE_XSAVE &&
!static_cpu_has(X86_FEATURE_XSAVE))
return false;
reg = guest_cpuid_get_register(vcpu, x86_feature);
if (!reg)
return false;