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

[Eric Auger]

On 3/6/24 21:45, Philippe Mathieu-Daudé wrote:
> 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?
It looks better. Nevertheless this was tested and it gives the expected
behavior.

Thanks

Eric
>
>> +    }
>> +    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(),
>>   };
>>   
>