Re: [PATCH v7 6/9] virtio-iommu: Add an option to define the input range width

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 6/3/24 21:32, 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>
> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> Reviewed-by: Cédric Le Goater <clg@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 67ea5022af..83a52cc446 100644
> --- a/include/hw/virtio/virtio-iommu.h
> +++ b/include/hw/virtio/virtio-iommu.h
> @@ -68,6 +68,7 @@ struct VirtIOIOMMU {
>       Notifier machine_done;
>       bool granule_frozen;
>       GranuleMode granule_mode;
> +    uint8_t aw_bits;
>   };
>   
>   #endif
> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> index aab97e1527..9b2813188b 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)
>        * in vfio realize
>        */
>       s->config.bypass = s->boot_bypass;
> -    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]");

Don't we need to return?

> +    }
> +    s->config.input_range.end =
> +        s->aw_bits == 64 ? UINT64_MAX : BIT_ULL(s->aw_bits) - 1;
>   
>       switch (s->granule_mode) {
>       case GRANULE_MODE_4K:
> @@ -1544,6 +1548,7 @@ static Property virtio_iommu_properties[] = {
>       DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
>       DEFINE_PROP_GRANULE_MODE("granule", VirtIOIOMMU, granule_mode,
>                                GRANULE_MODE_HOST),
> +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
>       DEFINE_PROP_END_OF_LIST(),
>   };
>