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| author | Paolo Bonzini <pbonzini@redhat.com> | 2017-12-13 15:51:32 +0300 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2018-01-16 18:34:13 +0300 |
| commit | 476b7adaa3272557168b287175b1e9e943913404 (patch) | |
| tree | 94fc0056f603db46d4026b5a179167783f728452 /arch/x86/kvm/x86.c | |
| parent | efdab992813fb2ed825745625b83c05032e9cda2 (diff) | |
| download | linux-476b7adaa3272557168b287175b1e9e943913404.tar.xz | |
KVM: x86: avoid unnecessary XSETBV on guest entry
xsetbv can be expensive when running on nested virtualization, try to
avoid it.
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Quan Xu <quan.xu0@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a3dd44bb6f1e..56d8a1e11e50 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -702,7 +702,8 @@ static 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 */ - xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0); + if (vcpu->arch.xcr0 != host_xcr0) + xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0); vcpu->guest_xcr0_loaded = 1; } } |