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  3. [PATCH v7 00/28] iommufd: Add vIOMMU infrastructure (Part-4 HW QUEUE)
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[PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id

Nicolin Chen posted 28 patches 3 months, 1 week ago
There is a newer version of this series
[PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id
Posted by Nicolin Chen 3 months, 1 week ago 
The "id" is too genernal to get its meaning easily. Rename it explicitly to
"virt_id" and update the kdocs for readability. No functional changes.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h | 7 ++++++-
 drivers/iommu/iommufd/driver.c          | 2 +-
 drivers/iommu/iommufd/viommu.c          | 4 ++--
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 4f5e8cd99c96..09f895638f68 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -634,7 +634,12 @@ struct iommufd_vdevice {
 	struct iommufd_object obj;
 	struct iommufd_viommu *viommu;
 	struct device *dev;
-	u64 id; /* per-vIOMMU virtual ID */
+
+	/*
+	 * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID of
+	 * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table
+	 */
+	u64 virt_id;
 };
 
 #ifdef CONFIG_IOMMUFD_TEST
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 2fee399a148e..887719016804 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -30,7 +30,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
 	xa_lock(&viommu->vdevs);
 	xa_for_each(&viommu->vdevs, index, vdev) {
 		if (vdev->dev == dev) {
-			*vdev_id = vdev->id;
+			*vdev_id = vdev->virt_id;
 			rc = 0;
 			break;
 		}
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 25ac08fbb52a..bc8796e6684e 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -111,7 +111,7 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj)
 	struct iommufd_viommu *viommu = vdev->viommu;
 
 	/* xa_cmpxchg is okay to fail if alloc failed xa_cmpxchg previously */
-	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
+	xa_cmpxchg(&viommu->vdevs, vdev->virt_id, vdev, NULL, GFP_KERNEL);
 	refcount_dec(&viommu->obj.users);
 	put_device(vdev->dev);
 }
@@ -150,7 +150,7 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
 		goto out_put_idev;
 	}
 
-	vdev->id = virt_id;
+	vdev->virt_id = virt_id;
 	vdev->dev = idev->dev;
 	get_device(idev->dev);
 	vdev->viommu = viommu;
-- 
2.43.0
Re: [PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id
Posted by Jason Gunthorpe 3 months ago 
On Thu, Jun 26, 2025 at 12:34:33PM -0700, Nicolin Chen wrote:
> The "id" is too genernal to get its meaning easily. Rename it explicitly to
> "virt_id" and update the kdocs for readability. No functional changes.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/iommufd/iommufd_private.h | 7 ++++++-
>  drivers/iommu/iommufd/driver.c          | 2 +-
>  drivers/iommu/iommufd/viommu.c          | 4 ++--
>  3 files changed, 9 insertions(+), 4 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason
RE: [PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id
Posted by Tian, Kevin 3 months, 1 week ago 
> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Friday, June 27, 2025 3:35 AM
> +
> +	/*
> +	 * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3,
> vDeviceID of
> +	 * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table
> +	 */
> +	u64 virt_id;

Just "vRID of Intel VT-d"? the current description is not very clear
to me.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Re: [PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id
Posted by Nicolin Chen 3 months, 1 week ago 
On Wed, Jul 02, 2025 at 09:40:50AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen <nicolinc@nvidia.com>
> > Sent: Friday, June 27, 2025 3:35 AM
> > +
> > +	/*
> > +	 * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3,
> > vDeviceID of
> > +	 * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table
> > +	 */
> > +	u64 virt_id;
> 
> Just "vRID of Intel VT-d"? the current description is not very clear
> to me.

Looks like we use "vRID of Intel VT-d to a Context Table" in the
Documentation/userspace-api/iommufd.rst, but forgot to change in
the uAPI header:
 * @virt_id: Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID
 *           of AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table

Let me correct both of them.

Thanks
Nicolin
Re: [PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id
Posted by Pranjal Shrivastava 3 months, 1 week ago 
On Thu, Jun 26, 2025 at 12:34:33PM -0700, Nicolin Chen wrote:
> The "id" is too genernal to get its meaning easily. Rename it explicitly to
> "virt_id" and update the kdocs for readability. No functional changes.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/iommufd/iommufd_private.h | 7 ++++++-
>  drivers/iommu/iommufd/driver.c          | 2 +-
>  drivers/iommu/iommufd/viommu.c          | 4 ++--
>  3 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
> index 4f5e8cd99c96..09f895638f68 100644
> --- a/drivers/iommu/iommufd/iommufd_private.h
> +++ b/drivers/iommu/iommufd/iommufd_private.h
> @@ -634,7 +634,12 @@ struct iommufd_vdevice {
>  	struct iommufd_object obj;
>  	struct iommufd_viommu *viommu;
>  	struct device *dev;
> -	u64 id; /* per-vIOMMU virtual ID */
> +
> +	/*
> +	 * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID of
> +	 * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table
> +	 */
> +	u64 virt_id;
>  };
>  
>  #ifdef CONFIG_IOMMUFD_TEST
> diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
> index 2fee399a148e..887719016804 100644
> --- a/drivers/iommu/iommufd/driver.c
> +++ b/drivers/iommu/iommufd/driver.c
> @@ -30,7 +30,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
>  	xa_lock(&viommu->vdevs);
>  	xa_for_each(&viommu->vdevs, index, vdev) {
>  		if (vdev->dev == dev) {
> -			*vdev_id = vdev->id;
> +			*vdev_id = vdev->virt_id;
>  			rc = 0;
>  			break;
>  		}
> diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
> index 25ac08fbb52a..bc8796e6684e 100644
> --- a/drivers/iommu/iommufd/viommu.c
> +++ b/drivers/iommu/iommufd/viommu.c
> @@ -111,7 +111,7 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj)
>  	struct iommufd_viommu *viommu = vdev->viommu;
>  
>  	/* xa_cmpxchg is okay to fail if alloc failed xa_cmpxchg previously */
> -	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> +	xa_cmpxchg(&viommu->vdevs, vdev->virt_id, vdev, NULL, GFP_KERNEL);
>  	refcount_dec(&viommu->obj.users);
>  	put_device(vdev->dev);
>  }
> @@ -150,7 +150,7 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
>  		goto out_put_idev;
>  	}
>  
> -	vdev->id = virt_id;
> +	vdev->virt_id = virt_id;
>  	vdev->dev = idev->dev;
>  	get_device(idev->dev);
>  	vdev->viommu = viommu;

Reviewed-by: Pranjal Shrivastava <praan@google.com>

> -- 
> 2.43.0
>

Patchew 2.1-devel-b67e4c2

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