Re: [CFT PATCH 0/2] KVM: support XSAVES usage in the host

From: Paolo Bonzini
Date: Mon Nov 24 2014 - 10:54:50 EST




On 24/11/2014 16:28, Nadav Amit wrote:
> Since kvm_load_guest_fpu is called before the guest_fpu is ever stored, there are 2 more problems that currently cause #GP:
> 1. XCOMP_BV[63] = 0
> 2. XSTATE_BV sets a bit (including bit 63) that is not set in XCOMP_BV (XCOMP_BV is initialised to zero).
>
> [see SDM 13.11 "OPERATION OF XRSTORSâ]
>
> Once I initialise XCOMP_BV to (1ull << 63) | XSTATE_BV, the guest runs successfully.
> I have not checked any other qemu functionality that might be affected by the patch.

Ah, so the problem is with KVM_SET_XSAVE. Thanks!

Paolo
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