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>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 38131c8340911c5c8068615472eff2b823aab09a..7141f81141a24d282a1e374145c46b0db3ddd70b 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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);
 

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 719fc3e15ea4e0181f314718951f9ff4fc2505c6..d2017302996c4a641ffca626ae75805770b6f6e9 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -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;