Commit 78958563 authored by Aaron Lewis's avatar Aaron Lewis Committed by Paolo Bonzini
Browse files

KVM: x86: Remove unneeded kvm_vcpu variable, guest_xcr0_loaded 



The kvm_vcpu variable, guest_xcr0_loaded, is a waste of an 'int'
and a conditional branch.  VMX and SVM are the only users, and both
unconditionally pair kvm_load_guest_xcr0() with kvm_put_guest_xcr0()
making this check unnecessary. Without this variable, the predicates in
kvm_load_guest_xcr0 and kvm_put_guest_xcr0 should match.

Suggested-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarAaron Lewis <aaronlewis@google.com>
Change-Id: I7b1eb9b62969d7bbb2850f27e42f863421641b23
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c034f2aa

arch/x86/kvm/x86.c

+5 −11
Original line number Diff line number Diff line
@@ -811,22 +811,16 @@ EXPORT_SYMBOL_GPL(kvm_lmsw); 
void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu)

{

	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&

			!vcpu->guest_xcr0_loaded) {

		/* kvm_set_xcr() also depends on this */

		if (vcpu->arch.xcr0 != host_xcr0)

	    vcpu->arch.xcr0 != host_xcr0)

		xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);

		vcpu->guest_xcr0_loaded = 1;

	}

}

EXPORT_SYMBOL_GPL(kvm_load_guest_xcr0);



void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)

{

	if (vcpu->guest_xcr0_loaded) {

		if (vcpu->arch.xcr0 != host_xcr0)

	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&

	    vcpu->arch.xcr0 != host_xcr0)

		xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);

		vcpu->guest_xcr0_loaded = 0;

	}

}

EXPORT_SYMBOL_GPL(kvm_put_guest_xcr0);

include/linux/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -278,7 +278,6 @@ struct kvm_vcpu { 
	struct mutex mutex;

	struct kvm_run *run;



	int guest_xcr0_loaded;

	struct swait_queue_head wq;

	struct pid __rcu *pid;

	int sigset_active;