Re: [PATCH v3] x86/hvm: Widen condition for is_hvm_pv_evtchn_domain() and report fix in CPUID

["Roger Pau Monné" <roger.pau@citrix.com>]

On Tue, May 24, 2022 at 05:14:12PM +0200, Jan Beulich wrote:
> On 18.05.2022 15:27, Jane Malalane wrote:
> > --- a/xen/arch/x86/include/asm/domain.h
> > +++ b/xen/arch/x86/include/asm/domain.h
> > @@ -14,8 +14,14 @@
> >  
> >  #define has_32bit_shinfo(d)    ((d)->arch.has_32bit_shinfo)
> >  
> > +/*
> > + * Set to true if either the global vector-type callback or per-vCPU
> > + * LAPIC vectors are used. Assume all vCPUs will use
> > + * HVMOP_set_evtchn_upcall_vector as long as the initial vCPU does.
> > + */
> >  #define is_hvm_pv_evtchn_domain(d) (is_hvm_domain(d) && \
> > -        (d)->arch.hvm.irq->callback_via_type == HVMIRQ_callback_vector)
> > +        ((d)->arch.hvm.irq->callback_via_type == HVMIRQ_callback_vector || \
> > +         (d)->vcpu[0]->arch.hvm.evtchn_upcall_vector))
> >  #define is_hvm_pv_evtchn_vcpu(v) (is_hvm_pv_evtchn_domain(v->domain))
> 
> I continue to think that with the vCPU0 dependency added to
> is_hvm_pv_evtchn_domain(), is_hvm_pv_evtchn_vcpu() should either
> be adjusted as well (to check the correct vCPU's field) or be
> deleted (and the sole caller be replaced).

I would be fine with replacing, the sole caller of
is_hvm_pv_evtchn_vcpu(v) is never reached if the upcall vector is in
use.

Thanks, Roger.