From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [CFT PATCH v2 0/2] KVM: support XSAVES usage in the host Date: Tue, 25 Nov 2014 15:17:20 +0100 Message-ID: <54748F70.70402@redhat.com> References: <1416847414-22253-1-git-send-email-pbonzini@redhat.com> <20141125101331.GA28985@kernel> <54745BB0.8080304@redhat.com> <400361E2-995A-44B4-B35A-0D35793B49DD@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Wanpeng Li , Linux Kernel Mailing List , kvm list , Nadav Amit , hpa@linux.intel.com To: Nadav Amit Return-path: In-Reply-To: <400361E2-995A-44B4-B35A-0D35793B49DD@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 25/11/2014 15:05, Nadav Amit wrote: > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 373b0ab9a32e..ca26681455c2 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -6955,6 +6955,9 @@ int fx_init(struct kvm_vcpu *vcpu) > > return err; > >=20 > > fpu_finit(&vcpu->arch.guest_fpu); > > + if (cpu_has_xsaves) > > + vcpu->arch.guest_fpu.state->xsave.xsave_hdr.xcomp_bv =3D > > + host_xcr0 | XSTATE_COMPACTION_ENABLED; > >=20 > > /* > > * Ensure guest xcr0 is valid for loading >=20 > The second version works for me (w/qemu v2.1.0; Linux 3.13 guest). I > did not need to apply this patch on top. [although I am not sure whet= her > relying on userspace to call KVM_SET_XSAVE early enough is a good pra= ctice]. Did you actually try the patch? :) If it works, I'm tempted to apply i= t anyway. > One disclaimer: Since I got limited time with the machine, I executed > a slightly modified kernel/qemu, and not the latest version. > Anyhow, I don=92t think these differences can have any impact. Yes, that is no problem. Paolo