On 18/10/2023 23:44, Jason Gunthorpe wrote:
> On Wed, Oct 18, 2023 at 09:27:05PM +0100, Joao Martins wrote:
>> Extend IOMMUFD_CMD_GET_HW_INFO op to query generic iommu capabilities for a
>> given device.
>>
>> Capabilities are IOMMU agnostic and use device_iommu_capable() API passing
>> one of the IOMMU_CAP_*. Enumerate IOMMU_CAP_DIRTY for now in the
>> out_capabilities field returned back to userspace.
>>
>> Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
>> ---
>> drivers/iommu/iommufd/device.c | 4 ++++
>> include/uapi/linux/iommufd.h | 11 +++++++++++
>> 2 files changed, 15 insertions(+)
>>
>> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
>> index e88fa73a45e6..71ee22dc1a85 100644
>> --- a/drivers/iommu/iommufd/device.c
>> +++ b/drivers/iommu/iommufd/device.c
>> @@ -1185,6 +1185,10 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd)
>> */
>> cmd->data_len = data_len;
>>
>> + cmd->out_capabilities = 0;
>> + if (device_iommu_capable(idev->dev, IOMMU_CAP_DIRTY))
>> + cmd->out_capabilities |= IOMMU_HW_CAP_DIRTY_TRACKING;
>> +
>> rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
>> out_free:
>> kfree(data);
>> diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
>> index efeb12c1aaeb..91de0043e73f 100644
>> --- a/include/uapi/linux/iommufd.h
>> +++ b/include/uapi/linux/iommufd.h
>> @@ -419,6 +419,14 @@ enum iommu_hw_info_type {
>> IOMMU_HW_INFO_TYPE_INTEL_VTD,
>> };
>>
>> +/**
>> + * enum iommufd_hw_info_capabilities
>> + * @IOMMU_CAP_DIRTY_TRACKING: IOMMU hardware support for dirty tracking
>> + */
>
> Lets write more details here, which iommufd APIs does this flag mean
> work.
>
I added this below. It is relatively brief as I expect people to read what each
of the API do. Unless I should be expanding in length here?
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index ef8a1243eb57..43ed2f208503 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -422,6 +422,12 @@ enum iommu_hw_info_type {
/**
* enum iommufd_hw_info_capabilities
* @IOMMU_CAP_DIRTY_TRACKING: IOMMU hardware support for dirty tracking
+ * If available, it means the following APIs
+ * are supported:
+ *
+ * IOMMU_HWPT_GET_DIRTY_IOVA
+ * IOMMU_HWPT_SET_DIRTY
+ *
*/
enum iommufd_hw_capabilities {
IOMMU_HW_CAP_DIRTY_TRACKING = 1 << 0,
