From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2] kvm/fpu: Enable fully eager restore kvm FPU Date: Wed, 05 Sep 2012 16:12:55 +0300 Message-ID: <50474FD7.3020301@redhat.com> References: <1346808370-28376-1-git-send-email-xudong.hao@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, xiantao.zhang@intel.com, Joerg.Roedel@amd.com To: Xudong Hao Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34736 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751067Ab2IENNB (ORCPT ); Wed, 5 Sep 2012 09:13:01 -0400 In-Reply-To: <1346808370-28376-1-git-send-email-xudong.hao@intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/05/2012 04:26 AM, Xudong Hao wrote: > Enable KVM FPU fully eager restore, if there is other FPU state which isn't > tracked by CR0.TS bit. > > Changes from v1: > Expand KVM_XSTATE_LAZY to 64 bits before negating it. > > Signed-off-by: Xudong Hao > --- > arch/x86/include/asm/kvm.h | 4 ++++ > arch/x86/kvm/x86.c | 13 ++++++++++++- > 2 files changed, 16 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 > #include > +#include > +#include > > /* Select x86 specific features in */ > #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/x86.c b/arch/x86/kvm/x86.c > index 20f2266..a632042 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5969,7 +5969,18 @@ 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 > + * by TS bit, there might be other FPU state is not tracked > + * by TS bit. Here it only make FPU deactivate request and do > + * FPU lazy restore for these cases: 1)xsave isn't enabled > + * in guest, 2)all guest FPU states can be tracked by TS bit. > + * For others, doing fully FPU eager restore. > + */ > + if (!kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) || > + !(vcpu->arch.xcr0 & ~((u64)KVM_XSTATE_LAZY))) > + kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu); > trace_kvm_fpu(0); > } > I think something is missing. This patch prevents KVM_REQ_DEACTIVATE_FPU, but the fpu may not be active when non-lazy bits are added to xcr0 (or cr4.osxsave is enabled). I think you need to activate the fpu at that time as well. -- error compiling committee.c: too many arguments to function