Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-11 06:31:49 +00:00
Code Issues Packages Projects Releases Wiki Activity

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

Browse Source 
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/x86/kvm/cpuid.h
View File

@ -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;

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

@ -5917,6 +5917,7 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
vcpu->arch.xsaves_enabled = guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
boot_cpu_has(X86_FEATURE_XSAVE) &&
boot_cpu_has(X86_FEATURE_XSAVES);
/* Update nrips enabled cache */

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

@ -4049,6 +4049,7 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
if (vmx_xsaves_supported()) {
/* Exposing XSAVES only when XSAVE is exposed */
bool xsaves_enabled =
boot_cpu_has(X86_FEATURE_XSAVE) &&
guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
guest_cpuid_has(vcpu, X86_FEATURE_XSAVES);