Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx> wrote: > 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)? I guess this paragraph is intended for me. As I said before, I got limited access to the machine - I will not be able to run these experiments before Sunday, and I am not sure that I will have time to fully debug it. If you insist, the very least please run some experiments running a 3.16 (or older) guest kernel and running 3.17 with ‘noxsaves’ kernel parameter. > + 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. xsaves is already enabled in KVM (the host) since 3.17. It just didn’t work… 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
