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KVM: x86: Add a helper to dedup loading guest/host XCR0 and XSS

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Add and use a helper, kvm_load_xfeatures(), to dedup the code that loads
guest/host xfeatures.

Opportunistically return early if X86_CR4_OSXSAVE is not set to reduce
indentations.

No functional change intended.

Suggested-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://patch.msgid.link/20251110050539.3398759-1-binbin.wu@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Binbin Wu
2025-11-10 13:05:39 +08:00
committed by Sean Christopherson
parent 7649412af3
commit 0b28f21ad4
1 changed files with 10 additions and 23 deletions
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33
arch/x86/kvm/x86.c
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@@ -1205,34 +1205,21 @@ void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_lmsw);
static void kvm_load_guest_xfeatures(struct kvm_vcpu *vcpu)
static void kvm_load_xfeatures(struct kvm_vcpu *vcpu, bool load_guest)
{
if (vcpu->arch.guest_state_protected)
return;
if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {
if (vcpu->arch.xcr0 != kvm_host.xcr0)
xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
vcpu->arch.ia32_xss != kvm_host.xss)
wrmsrq(MSR_IA32_XSS, vcpu->arch.ia32_xss);
}
}
static void kvm_load_host_xfeatures(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.guest_state_protected)
if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE))
return;
if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {
if (vcpu->arch.xcr0 != kvm_host.xcr0)
xsetbv(XCR_XFEATURE_ENABLED_MASK, kvm_host.xcr0);
if (vcpu->arch.xcr0 != kvm_host.xcr0)
xsetbv(XCR_XFEATURE_ENABLED_MASK,
load_guest ? vcpu->arch.xcr0 : kvm_host.xcr0);
if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
vcpu->arch.ia32_xss != kvm_host.xss)
wrmsrq(MSR_IA32_XSS, kvm_host.xss);
}
if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
vcpu->arch.ia32_xss != kvm_host.xss)
wrmsrq(MSR_IA32_XSS, load_guest ? vcpu->arch.ia32_xss : kvm_host.xss);
}
static void kvm_load_guest_pkru(struct kvm_vcpu *vcpu)
@@ -11271,7 +11258,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (vcpu->arch.guest_fpu.xfd_err)
wrmsrq(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
kvm_load_guest_xfeatures(vcpu);
kvm_load_xfeatures(vcpu, true);
if (unlikely(vcpu->arch.switch_db_regs &&
!(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH))) {
@@ -11367,7 +11354,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
vcpu->mode = OUTSIDE_GUEST_MODE;
smp_wmb();
kvm_load_host_xfeatures(vcpu);
kvm_load_xfeatures(vcpu, false);
/*
* Sync xfd before calling handle_exit_irqoff() which may