On Fri, Nov 21, 2014 at 03:46:55PM +0100, Paolo Bonzini wrote: > > > On 20/11/2014 17:34, Nadav Amit wrote: > > Fenghua, > > > > I got KVM (v3.17) crashing on a machine that supports XRSTORS - It appears to get a #GP when it is trying to load the guest FPU. > > One reason for the #GP is that XCOMP_BV[63] is zeroed on the guest_fpu, but I am not sure it is the only problem. > > Was KVM ever tested with XRSTORS? > > What is the content of the CPUID[EAX=13,ECX=0] and CPUID[EAX=13,ECX=1] > leaves on the host? > > Fenghua, which processors have XSAVEC, which have XGETBV with ECX=1, and > which have XSAVES? We need to expose this in QEMU, for which I can send > a patch later today or next week (CCing Eduardo for this). > > We will also have to uncompact the XSAVE area either in KVM_GET_XSAVE or > in QEMU. It's probably not hard to do it in the kernel. Oh, now I see that KVM uses xsave_state(), which uses XSAVEOPT and XSAVES depending on the host CPU features. I didn't know that. QEMU already expects the standard format to be part of the KVM_GET_XSAVE ABI. So this would already cause problems in host CPUs supporting XSAVES, even if XSAVES is not exposed to guests yet. -- Eduardo -- 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
