On Tue, Nov 16, 2021, Thomas Gleixner wrote: > Now you could argue that the interrupt/softirq XSAVES should also read > the XFD MSR and save it in guest_fpstate.xfd. Same in schedule() > and kvm_put_guest_fpu(), i.e: > > XSAVES > if (fpstate->is_guest) { > rdmsrl(XFD, xfd); > fpstate->xfd = xfd; > __this_cpu_write(..., xfd); > } > > We can do that, but I'm unhappy about this conditional in schedule(). So > I was asking for doing a simple KVM only solution first: Ah, the schedule() conditional is the part I was missing. Thanks!