[PATCH v2 47/49] KVM: x86: Drop superfluous host XSAVE check when adjusting guest XSAVES caps

From: Sean Christopherson
Date: Fri May 17 2024 - 13:54:11 EST


Drop the manual boot_cpu_has() checks on XSAVE when adjusting the guest's
XSAVES capabilities now that guest cpu_caps incorporates KVM's support.
The guest's cpu_caps are initialized from kvm_cpu_caps, which are in turn
initialized from boot_cpu_data, i.e. checking guest_cpu_cap_has() also
checks host/KVM capabilities (which is the entire point of cpu_caps).

Cc: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/svm/svm.c | 1 -
arch/x86/kvm/vmx/vmx.c | 3 +--
2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 06770b60c0ba..4aaffbf22531 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4340,7 +4340,6 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
* the guest read/write access to the host's XSS.
*/
guest_cpu_cap_change(vcpu, X86_FEATURE_XSAVES,
- boot_cpu_has(X86_FEATURE_XSAVE) &&
boot_cpu_has(X86_FEATURE_XSAVES) &&
guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVE));

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 741961a1edcc..6fbdf520c58b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7833,8 +7833,7 @@ void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
* to the guest. XSAVES depends on CR4.OSXSAVE, and CR4.OSXSAVE can be
* set if and only if XSAVE is supported.
*/
- if (!boot_cpu_has(X86_FEATURE_XSAVE) ||
- !guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVE))
+ if (!guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVE))
guest_cpu_cap_clear(vcpu, X86_FEATURE_XSAVES);

vmx_setup_uret_msrs(vmx);
--
2.45.0.215.g3402c0e53f-goog