Re: [PATCH v3 22/22] kvm: x86: Disable interception for IA32_XFD on demand

[Sean Christopherson]

On Tue, Jan 04, 2022, Paolo Bonzini wrote:
> On 12/29/21 02:04, Sean Christopherson wrote:
> > 
> > Speaking of nested, interception of #NM in vmx_update_exception_bitmap() is wrong
> > with respect to nested guests.  Until XFD is supported for L2, which I didn't see
> > in this series, #NM should not be intercepted while L2 is running.
> 
> Why wouldn't L2 support XFD, since there are no new VMCS bits?  As long as
> L0 knows what to do with XFD and XFD_ERR, it will do the right thing no
> matter if L1 or L2 is running.

I incorrectly assumed there was something L0 needed to do in order to support
nested XFD.