> -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > Behalf Of Avi Kivity > Sent: Friday, September 14, 2012 12:39 AM > To: Hao, Xudong > Cc: kvm@xxxxxxxxxxxxxxx; Zhang, Xiantao > Subject: Re: [PATCH v3] kvm/fpu: Enable fully eager restore kvm FPU > > On 09/12/2012 11:10 AM, Xudong Hao wrote: > > Enable KVM FPU fully eager restore, if there is other FPU state which isn't > > tracked by CR0.TS bit. > > > > v3 changes from v2: > > - Make fpu active explicitly while guest xsave is enabling and non-lazy xstate > bit > > exist. > > > > v2 changes from v1: > > - Expand KVM_XSTATE_LAZY to 64 bits before negating it. > > > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > index 248c2b4..853e875 100644 > > --- a/arch/x86/kvm/vmx.c > > +++ b/arch/x86/kvm/vmx.c > > @@ -3028,6 +3028,8 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, > unsigned long cr0) > > > > if (!vcpu->fpu_active) > > hw_cr0 |= X86_CR0_TS | X86_CR0_MP; > > + else > > + hw_cr0 &= ~(X86_CR0_TS | X86_CR0_MP); > > > > Why? The guest may wish to receive #NM faults. > Hmm, I wanted to clear TS bit to avoid vmexit if fpu_active=1, but missing to consider the guest inside. > > vmcs_writel(CR0_READ_SHADOW, cr0); > > vmcs_writel(GUEST_CR0, hw_cr0); > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 20f2266..183cf60 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -560,6 +560,8 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, > u64 xcr) > > return 1; > > if (xcr0 & ~host_xcr0) > > return 1; > > + if (xcr0 & ~((u64)KVM_XSTATE_LAZY)) > > + vcpu->fpu_active = 1; > > vcpu->arch.xcr0 = xcr0; > > vcpu->guest_xcr0_loaded = 0; > > return 0; > > @@ -5969,7 +5971,18 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) > > vcpu->guest_fpu_loaded = 0; > > fpu_save_init(&vcpu->arch.guest_fpu); > > ++vcpu->stat.fpu_reload; > > - kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu); > > + /* > > + * Currently KVM trigger FPU restore by #NM (via CR0.TS), > > + * till now only XCR0.bit0, XCR0.bit1, XCR0.bit2 is tracked > > "currently", "till now", don't tell someone reading the code in six > months anything. Just say how the code works. > Okay. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
