Commit 0b28f21a authored by Binbin Wu's avatar Binbin Wu Committed by Sean Christopherson
Browse files

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



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: default avatarChao Gao <chao.gao@intel.com>
Reviewed-by: default avatarChao Gao <chao.gao@intel.com>
Signed-off-by: default avatarBinbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Link: https://patch.msgid.link/20251110050539.3398759-1-binbin.wu@linux.intel.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 7649412a

arch/x86/kvm/x86.c

+10 −23
Original line number Diff line number Diff line
@@ -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);

		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);

	}

		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