On Fri, Sep 14, 2012 at 08:54:40AM +0000, Hao, Xudong wrote: > > -----Original Message----- > > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > > Behalf Of Marcelo Tosatti > > Sent: Friday, September 14, 2012 12:29 AM > > To: Hao, Xudong; Avi Kivity > > Cc: kvm@xxxxxxxxxxxxxxx; Zhang, Xiantao > > Subject: Re: [PATCH v3] kvm/fpu: Enable fully eager restore kvm FPU > > > > On Thu, Sep 13, 2012 at 01:26:36PM -0300, Marcelo Tosatti wrote: > > > On Wed, Sep 12, 2012 at 04:10:24PM +0800, 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. > > > > > > How about a "guest_xcr0_can_lazy_saverestore" bool to control this? > > > It only needs to be updated when guest xcr0 is updated. > > > > > > That seems cleaner. Avi? > > > > Reasoning below. > > > > > > v2 changes from v1: > > > > - Expand KVM_XSTATE_LAZY to 64 bits before negating it. > > > > > > > > Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx> > > > > --- > > > > arch/x86/include/asm/kvm.h | 4 ++++ > > > > arch/x86/kvm/vmx.c | 2 ++ > > > > arch/x86/kvm/x86.c | 15 ++++++++++++++- > > > > 3 files changed, 20 insertions(+), 1 deletions(-) > > > > > > > > diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h > > > > index 521bf25..4c27056 100644 > > > > --- a/arch/x86/include/asm/kvm.h > > > > +++ b/arch/x86/include/asm/kvm.h > > > > @@ -8,6 +8,8 @@ > > > > > > > > #include <linux/types.h> > > > > #include <linux/ioctl.h> > > > > +#include <asm/user.h> > > > > +#include <asm/xsave.h> > > > > > > > > /* Select x86 specific features in <linux/kvm.h> */ > > > > #define __KVM_HAVE_PIT > > > > @@ -30,6 +32,8 @@ > > > > /* Architectural interrupt line count. */ > > > > #define KVM_NR_INTERRUPTS 256 > > > > > > > > +#define KVM_XSTATE_LAZY (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) > > > > + > > > > struct kvm_memory_alias { > > > > __u32 slot; /* this has a different namespace than memory slots */ > > > > __u32 flags; > > > > 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); > > > > > > > > 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; > > > > This is confusing. The variable allows to decrease the number of places > > the decision is made. > > > > Hi, Marcelo, What does it mean? See Avi's reply. Better create a function lazy_fpu_allowed Which can be used to decide whether or not to allow guest owning FPU state. -- 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
