Hi all, On Tue, Nov 25, 2014 at 04:50:06PM +0200, Nadav Amit wrote: > >> On Nov 25, 2014, at 16:17, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >> >> >> >> 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; >>>> >>>> fpu_finit(&vcpu->arch.guest_fpu); >>>> + if (cpu_has_xsaves) >>>> + vcpu->arch.guest_fpu.state->xsave.xsave_hdr.xcomp_bv = >>>> + host_xcr0 | XSTATE_COMPACTION_ENABLED; >>>> >>>> /* >>>> * Ensure guest xcr0 is valid for loading >>> >>> The second version works for me (w/qemu v2.1.0; Linux 3.13 guest). I Could you try 3.17 guest which has xsaves enabled? Because I'm not sure if the below codes from Paolo is enough to mask XSAVES, should we also add F(XSAVES)? + const u32 kvm_supported_word10_x86_features = + F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1); + In addition, the 3.17 guest is still hang as I mentioned even if I add the F(XSAVES) to the kvm_supported_word10_x86_features. >>> did not need to apply this patch on top. [although I am not sure whether >>> relying on userspace to call KVM_SET_XSAVE early enough is a good practice]. >> >> Did you actually try the patch? :) If it works, I'm tempted to apply it >> anyway. >Yes, I tried it both with and without this patch. >Due to time constraints I only tested minimal functionality (Linux boot). >I will run more tests in the near future. Anyhow, you can put the: > >Tested-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx> > >> >>> 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’t think these differences can have any impact. >> >> Yes, that is no problem. > >I am just worried that Wanpeng reported it fails, while I report it works... > I have another patch which enable xsaves in KVM and the patch is still under debug with Paolo's patch "KVM: x86: support XSAVES usage in the host", so the 1/2 patch from Paolo can be dropped if my patch is ready. Anyway, a quick fix is needed before enable xsaves in kvm. Regards, Wanpeng Li >Nadav -- 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
