Hi Nadav, On Wed, Nov 26, 2014 at 11:00:34AM +0200, Nadav Amit wrote: >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… > Not yet, it is enabled in native currrently instead of vmx and my patch is still under debug. 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
