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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: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: I7b1eb9b62969d7bbb2850f27e42f863421641b23
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Aaron Lewis 2019-10-21 16:30:22 -07:00 committed by Paolo Bonzini
parent c034f2aa86
commit 78958563d8
2 changed files with 5 additions and 12 deletions
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16
arch/x86/kvm/x86.c
View File

@ -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)
xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
vcpu->guest_xcr0_loaded = 1;
}
vcpu->arch.xcr0 != host_xcr0)
xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
}
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)
xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);
vcpu->guest_xcr0_loaded = 0;
}
if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&
vcpu->arch.xcr0 != host_xcr0)
xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);
}
EXPORT_SYMBOL_GPL(kvm_put_guest_xcr0);

1
include/linux/kvm_host.h
View File

@ -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;