Re: [PATCH v2 6/8] x86/iommu: call pi_update_irte through an hvm_function callback

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

On 1/12/23 14:37, Jan Beulich wrote:
> On 12.01.2023 13:16, Jan Beulich wrote:
> > On 04.01.2023 09:45, Xenia Ragiadakou wrote:
> > > --- a/xen/arch/x86/hvm/vmx/vmx.c
> > > +++ b/xen/arch/x86/hvm/vmx/vmx.c
> > > @@ -2143,6 +2143,14 @@ static bool cf_check vmx_test_pir(const struct vcpu *v, 
> > > uint8_t vec)
> > >       return pi_test_pir(vec, &v->arch.hvm.vmx.pi_desc);
> > >   }
> > >   
> > > +static int cf_check vmx_pi_update_irte(const struct vcpu *v,
> > > +                                       const struct pirq *pirq, uint8_t gvec)
> > > +{
> > > +    const struct pi_desc *pi_desc = v ? &v->arch.hvm.vmx.pi_desc : NULL;
> > > +
> > > +    return pi_update_irte(pi_desc, pirq, gvec);
> > > +}
> > This being the only caller of pi_update_irte(), I don't see the point in
> > having the extra wrapper. Adjust pi_update_irte() such that it can be
> > used as the intended hook directly. Plus perhaps prefix it with vtd_.
> Plus move it to vtd/x86/hvm.c (!HVM builds shouldn't need it), albeit I
> realize this could be done independent of your work. In principle the
> function shouldn't be VT-d specific (and could hence live in x86/hvm.c),
> as msi_msg_write_remap_rte() is already available as IOMMU hook anyway,
> provided struct pi_desc turns out compatible with what's going to be
> needed for AMD.
Since the posted interrupt descriptor is vmx specific while 
msi_msg_write_remap_rte is iommu specific, can I propose the following:
- Keep the name as is (i.e vmx_pi_update_irte) and keep its definition 
in xen/arch/x86/hvm/vmx/vmx.c
- Open code pi_update_irte() inside the body of vmx_pi_update_irte() but 
replace intel-specific msi_msg_write_remap_rte() with generic 
iommu_update_ire_from_msi().
Does this approach make sense?

--
Xenia