On Mon, Feb 7, 2022 at 6:00 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 2/7/22 21:24, Leonardo Bras Soares Passos wrote: > >> With this patch, > >> we have to reason about the effect of calling KVM_SET_CPUID2 twice calls > >> back to back. I think an "&=" would be wrong in that case. > > > > So, you suggest something like this ? > > > > vcpu->arch.guest_fpu.fpstate->xfeatures = > > fpu_user_cfg.default_features & vcpu->arch.guest_supported_xcr0; > > > > Yes, but you need to change user_xfeatures instead of xfeatures. > KVM_GET_XSAVE and KVM_SET_XSAVE will take it into account automatically: > > - KVM_GET_XSAVE: fpu_copy_guest_fpstate_to_uabi -> __copy_xstate_to_uabi_buf > > - KVM_SET_XSAVE: fpu_copy_uabi_to_guest_fpstate -> > copy_uabi_from_kernel_to_xstate -> copy_uabi_to_xstate -> > validate_user_xstate_buffer Ok, I understand how this replaces patch 2/2, so no issue on that. About patch 1/2, you suggest that instead of fixing what we save in the regs buffer, we fix only what we want to return to the user when they call KVM_GET_XSAVE, is that correct? > > Paolo >
