Re: [PATCH v4 2/3] virtio-iommu: Add a granule property

[Eric Auger <eric.auger@redhat.com>]

On 2/23/24 08:57, Philippe Mathieu-Daudé wrote:
> On 23/2/24 08:27, Eric Auger wrote:
>> This allows to choose which granule will be used by
>> default by the virtio-iommu. Current page size mask
>> default is qemu_target_page_mask so this translates
>> into a 4K granule.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>>
>> v3 -> v4:
>> - granule_mode introduction moved to that patch
>> ---
>>   include/hw/virtio/virtio-iommu.h |  1 +
>>   hw/virtio/virtio-iommu.c         | 27 ++++++++++++++++++++++++---
>>   qemu-options.hx                  |  3 +++
>>   3 files changed, 28 insertions(+), 3 deletions(-)
>
>
>> @@ -1324,7 +1324,26 @@ static void
>> virtio_iommu_device_realize(DeviceState *dev, Error **errp)
>>        * in vfio realize
>>        */
>>       s->config.bypass = s->boot_bypass;
>> -    s->config.page_size_mask = qemu_target_page_mask();
>> +
>> +    switch (s->granule_mode) {
>> +    case GRANULE_MODE_4K:
>> +        s->config.page_size_mask = ~0xFFF;
>
> Alternatively:
>
>           s->config.page_size_mask = -(4 * KiB);
Yep that's more readable.

Thanks

Eric
>
>> +        break;
>> +    case GRANULE_MODE_8K:
>> +        s->config.page_size_mask = ~0x1FFF;
>
>           s->config.page_size_mask = -(8 * KiB);
>
>> +        break;
>> +    case GRANULE_MODE_16K:
>> +        s->config.page_size_mask = ~0x3FFF;
>
> ...
>
>> +        break;
>> +    case GRANULE_MODE_64K:
>> +        s->config.page_size_mask = ~0xFFFF;
>> +        break;
>> +    case GRANULE_MODE_HOST:
>> +        s->config.page_size_mask = qemu_real_host_page_mask();
>> +        break;
>> +    default:
>> +        error_setg(errp, "Unsupported granule mode");
>> +    }
>