[PATCH v4 14/14] iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU
Baolu Lu
baolu.lu at linux.intel.com
Mon Jan 6 21:54:00 PST 2025
On 1/7/25 12:36, Nicolin Chen wrote:
> On Mon, Jan 06, 2025 at 10:46:21AM -0800, Nicolin Chen wrote:
>> On Mon, Jan 06, 2025 at 11:01:32AM +0800, Baolu Lu wrote:
>>> Nit: I think it would be more readable to add a check in the vevent
>>> reporting helper.
>>>
>>> diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
>>> index 77c34f8791ef..ccada0ada5ff 100644
>>> --- a/drivers/iommu/iommufd/driver.c
>>> +++ b/drivers/iommu/iommufd/driver.c
>>> @@ -86,6 +86,9 @@ int iommufd_viommu_report_event(struct iommufd_viommu
>>> *viommu,
>>> if (WARN_ON_ONCE(!data_len || !event_data))
>>> return -EINVAL;
>>>
>>> + if (WARN_ON_ONCE(type != IOMMU_VEVENTQ_TYPE_ARM_SMMUV3))
>>> + return -EINVAL;
>>> +
>> Hmm, that's a good point I think.
>>
>>> down_read(&viommu->veventqs_rwsem);
>>>
>>> veventq = iommufd_viommu_find_veventq(viommu, type);
>> ^
>> |
>> We actually have been missing a type validation entirely, so the
>> type could have been rejected by this function. Perhaps we should
>> add a static list of supported types to struct iommufd_viommu_ops
>> for drivers to report so that then the core could reject from the
>> first place during a vEVENTQ allocation.
> I added something like this. Will send a v5.
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> index 0c7a5894ba07..348179f3cf2a 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> @@ -399,9 +399,15 @@ static int arm_vsmmu_cache_invalidate(struct iommufd_viommu *viommu,
> return ret;
> }
>
> +static bool arm_vsmmu_supports_veventq(unsigned int type)
> +{
> + return type == IOMMU_VIOMMU_TYPE_ARM_SMMUV3;
Do you need to check the hardware capabilities before reporting this? I
am not familiar with the ARM architecture, but typically it's better to
make it like this,
static bool arm_vsmmu_supports_veventq(struct iommufd_viommu *viommu,
enum iommu_veventq_type type)
{
if (type != IOMMU_VEVENTQ_TYPE_ARM_SMMUV3)
return false;
if (hardware_not_capable(viommu))
return false;
return true;
}
> +}
> +
> static const struct iommufd_viommu_ops arm_vsmmu_ops = {
> .alloc_domain_nested = arm_vsmmu_alloc_domain_nested,
> .cache_invalidate = arm_vsmmu_cache_invalidate,
> + .supports_veventq = arm_vsmmu_supports_veventq,
> };
Others look good to me.
Thanks,
baolu
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