On 10/15/2021 3:14 AM, Thomas Gleixner wrote: > Paolo, > [...] > >> vcpu_create() > >> > >> fpu_init_fpstate_user(guest_fpu, supported_xcr0) > >> > >> That will (it does not today) do: > >> > >> guest_fpu::__state_perm = supported_xcr0 & > >> xstate_get_group_perm(); > >> > >> The you have the information you need right in the guest FPU. > > > > Good, I wasn't aware of the APIs that will be there. > > Me neither, but that's a pretty obvious consequence of the work I'm doing > for AMX. So I made it up for you. :) Do you mean that fpu_init_fpstate_user() will be updated to add supported_xcr0 later? :) I'm thinking if guest_fpu::xfd is good to directly initialize as user's init_fpstate.xfd. Because before guest initializes XFD, "hardware" is reset value. So it would be better to make guest_fpu::xfd the same so no need to reload zero before vmenter during this time. Thanks, Jing
