On 15/11/2017 15:43, Rik van Riel wrote: >> Rik, be careful with VM migration. with you patch, I don't think you >> could load fpu/xstate >> context accurately after VM migration. > Can you explain why you believe that? > > Getting the guest FPU or XSTATE is done under the vcpu->mutex. > > This patch switches out guest and userspace FPU/XSTATE under the > vcpu->mutex, and switches it back before releasing the vcpu->mutex. > > By the time a KVM_GET_FPU has obtained the vcpu->mutex, the guest > FPU state will be in vcpu->arch.guest_fpu.state, where you expect > it to be. > > What am I missing? Nothing as far as I can see. :) Paolo
