Re: [Xen-devel] [PATCH XEN] x86/pt: add a MSI unmask flag to XEN_DOMCTL_bind_pt_irq

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 24.08.17 at 12:12, <roger.pau@xxxxxxxxxx> wrote:
> On Thu, Aug 24, 2017 at 04:07:40AM -0600, Jan Beulich wrote:
>> >>> On 24.08.17 at 11:47, <roger.pau@xxxxxxxxxx> wrote:
>> > @@ -438,6 +439,22 @@ int pt_irq_create_bind(
>> >              pi_update_irte(vcpu ? &vcpu->arch.hvm_vmx.pi_desc : NULL,
>> >                             info, pirq_dpci->gmsi.gvec);
>> >  
>> > +        if ( pt_irq_bind->u.msi.gflags & VMSI_UNMASKED )
>> > +        {
>> > +            struct irq_desc *desc = irq_to_desc(info->arch.irq);
>> > +            unsigned long flags;
>> > +
>> > +            if ( !desc )
>> > +            {
>> > +                pt_irq_destroy_bind(d, pt_irq_bind);
>> > +                return -EINVAL;
>> > +            }
>> > +
>> > +            spin_lock_irqsave(&desc->lock, flags);
>> > +            guest_mask_msi_irq(desc, false);
>> > +            spin_unlock_irqrestore(&desc->lock, flags);
>> > +        }
>> > +
>> >          break;
>> >      }
>> 
>> I think you would better use pirq_spin_lock_irq_desc() here. And
>> wouldn't the addition better be moved up a little (perhaps right
>> after the dropping of the domain's event lock)?
> 
> Shouldn't the unmask happen after the posted interrupt is setup? Or it
> doesn't really matter?
> 
> I though it was safer to unmask once the bind process was finished.

Yeah, I'm not entirely certain either, hence I've put it as a question.
Kevin, Chao?

Jan


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