On Wednesday, December 15, 2021 9:43 PM, Paolo Bonzini wrote: > It's still easier to return the full size of the buffer from > KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2). It makes the userspace code a > bit easier. OK. For the "full size" returned to userspace, would you prefer to directly use the value retrieved from guest CPUID(0xd), or get it from guest_fpu (i.e. fpstate->user_size)? (retrieved from CPUID will be the max size and should work fine as well) > > I'm also thinking that I prefer KVM_GET_XSAVE2 to > KVM_ENABLE_CAP(KVM_CAP_XSAVE2), after all. Since it would be a > backwards-incompatible change to an _old_ ioctl (KVM_GET_XSAVE), I prefer > to limit the ways that userspace can shoot itself in the foot. OK, we will use KVM_GET_XSAVE2. Thanks, Wei
