Re: [PATCH v2 1/3] virtio-iommu: Add an option to define the input range width

[Cédric Le Goater]

On 2/5/24 10:14, Cédric Le Goater wrote:
> On 2/1/24 17:32, Eric Auger wrote:
> > aw-bits is a new option that allows to set the bit width of
> > the input address range. This value will be used as a default for
> > the device config input_range.end. By default it is set to 64 bits
> > which is the current value.
> >
> > Signed-off-by: Eric Auger <eric.auger@redhat.com>
> >
> > ---
> >
> > v1 -> v2:
> > - Check the aw-bits value is within [32,64]
> > ---
> >   include/hw/virtio/virtio-iommu.h | 1 +
> >   hw/virtio/virtio-iommu.c         | 7 ++++++-
> >   2 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h
> > index 781ebaea8f..5fbe4677c2 100644
> > --- a/include/hw/virtio/virtio-iommu.h
> > +++ b/include/hw/virtio/virtio-iommu.h
> > @@ -66,6 +66,7 @@ struct VirtIOIOMMU {
> >       bool boot_bypass;
> >       Notifier machine_done;
> >       bool granule_frozen;
> > +    uint8_t aw_bits;
> >   };
> >   #endif
> > diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> > index ec2ba11d1d..7870bdbeee 100644
> > --- a/hw/virtio/virtio-iommu.c
> > +++ b/hw/virtio/virtio-iommu.c
> > @@ -1314,7 +1314,11 @@ static void virtio_iommu_device_realize(DeviceState 
> > *dev, Error **errp)
> >        */
> >       s->config.bypass = s->boot_bypass;
> >       s->config.page_size_mask = qemu_real_host_page_mask();
> > -    s->config.input_range.end = UINT64_MAX;
> > +    if (s->aw_bits < 32 || s->aw_bits > 64) {
> > +        error_setg(errp, "aw-bits must be within [32,64]");
> > +    }
> > +    s->config.input_range.end =
> > +        s->aw_bits == 64 ? UINT64_MAX : BIT_ULL(s->aw_bits) - 1;
>
>
> This could be simplified :
>
>    s->config.input_range.end = BIT_ULL(s->aw_bits) - 1;

Forget that. We would need a int28.

Thanks,

C.



> Anyhow,
>
>
> Reviewed-by: Cédric Le Goater <clg@redhat.com>
>
> Thanks,
>
> C.
>
>
>
> >       s->config.domain_range.end = UINT32_MAX;
> >       s->config.probe_size = VIOMMU_PROBE_SIZE;
> > @@ -1525,6 +1529,7 @@ static Property virtio_iommu_properties[] = {
> >       DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
> >                        TYPE_PCI_BUS, PCIBus *),
> >       DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
> > +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
> >       DEFINE_PROP_END_OF_LIST(),
> >   };