From 476b7adaa3272557168b287175b1e9e943913404 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 13 Dec 2017 13:51:32 +0100 Subject: 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 Reviewed-by: Wanpeng Li Reviewed-by: Quan Xu Signed-off-by: Paolo Bonzini Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86') 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; } } -- cgit v1.2.3-55-g7522