[PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Nicolin Chen]

Following the previous vIOMMU series, this adds another vDEVICE structure,
representing the association from an iommufd_device to an iommufd_viommu.
This gives the whole architecture a new "v" layer:
  _______________________________________________________________________
 |                      iommufd (with vIOMMU/vDEVICE)                    |
 |                        _____________      _____________               |
 |                       |             |    |             |              |
 |      |----------------|    vIOMMU   |<---|   vDEVICE   |<------|      |
 |      |                |             |    |_____________|       |      |
 |      |     ______     |             |     _____________     ___|____  |
 |      |    |      |    |             |    |             |   |        | |
 |      |    | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
 |      |    |______|    |_____________|    |_____________|   |________| |
 |______|________|______________|__________________|_______________|_____|
        |        |              |                  |               |
  ______v_____   |        ______v_____       ______v_____       ___v__
 |   struct   |  |  PFN  |  (paging)  |     |  (nested)  |     |struct|
 |iommu_device|  |------>|iommu_domain|<----|iommu_domain|<----|device|
 |____________|   storage|____________|     |____________|     |______|

This vDEVICE object is used to collect and store all vIOMMU-related device
information/attributes in a VM. As an initial series for vDEVICE, add only
the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM:
e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to
a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID
of the device against the physical IOMMU instance. This is essential for a
vIOMMU-based invalidation, where the request contains a device's vID for a
device cache flush, e.g. ATC invalidation.

Therefore, with this vDEVICE object, support a vIOMMU-based invalidation,
by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache
with a given driver data.

As for the implementation of the series, add driver support in ARM SMMUv3
for a real world use case.

This series is on Github:
https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v6
(QEMU branch for testing will be provided in Jason's nesting series)

Changelog
v6
 * Fixed kdoc in the uAPI header
 * Fixed indentations in iommufd.rst
 * Replaced vdev->idev with vdev->dev
 * Added "Reviewed-by" from Kevin and Jason
 * Updated kdoc of struct iommu_vdevice_alloc
 * Fixed lockdep function call in iommufd_viommu_find_dev
 * Added missing iommu_dev validation between viommu and idev
 * Skipped SMMUv3 driver changes (to post in a separate series)
 * Replaced !cache_invalidate_user in WARN_ON of the allocation path
   with cache_invalidate_user validation in iommufd_hwpt_invalidate
v5
 https://lore.kernel.org/all/cover.1729897278.git.nicolinc@nvidia.com/
 * Dropped driver-allocated vDEVICE support
 * Changed vdev_to_dev helper to iommufd_viommu_find_dev
v4
 https://lore.kernel.org/all/cover.1729555967.git.nicolinc@nvidia.com/
 * Added missing brackets in switch-case
 * Fixed the unreleased idev refcount issue
 * Reworked the iommufd_vdevice_alloc allocator
 * Dropped support for IOMMU_VIOMMU_TYPE_DEFAULT
 * Added missing TEST_LENGTH and fail_nth coverages
 * Added a verification to the driver-allocated vDEVICE object
 * Added an iommufd_vdevice_abort for a missing mutex protection
 * Added a u64 structure arm_vsmmu_invalidation_cmd for user command
   conversion
v3
 https://lore.kernel.org/all/cover.1728491532.git.nicolinc@nvidia.com/
 * Added Jason's Reviewed-by
 * Split this invalidation part out of the part-1 series
 * Repurposed VDEV_ID ioctl to a wider vDEVICE structure and ioctl
 * Reduced viommu_api functions by allowing drivers to access viommu
   and vdevice structure directly
 * Dropped vdevs_rwsem by using xa_lock instead
 * Dropped arm_smmu_cache_invalidate_user
v2
 https://lore.kernel.org/all/cover.1724776335.git.nicolinc@nvidia.com/
 * Limited vdev_id to one per idev
 * Added a rw_sem to protect the vdev_id list
 * Reworked driver-level APIs with proper lockings
 * Added a new viommu_api file for IOMMUFD_DRIVER config
 * Dropped useless iommu_dev point from the viommu structure
 * Added missing index numnbers to new types in the uAPI header
 * Dropped IOMMU_VIOMMU_INVALIDATE uAPI; Instead, reuse the HWPT one
 * Reworked mock_viommu_cache_invalidate() using the new iommu helper
 * Reordered details of set/unset_vdev_id handlers for proper lockings
v1
 https://lore.kernel.org/all/cover.1723061377.git.nicolinc@nvidia.com/

Thanks!
Nicolin

Jason Gunthorpe (1):
  iommu: Add iommu_copy_struct_from_full_user_array helper

Nicolin Chen (9):
  iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl
  iommufd/selftest: Add IOMMU_VDEVICE_ALLOC test coverage
  iommu/viommu: Add cache_invalidate to iommufd_viommu_ops
  iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE
  iommufd/viommu: Add iommufd_viommu_find_dev helper
  iommufd/selftest: Add mock_viommu_cache_invalidate
  iommufd/selftest: Add IOMMU_TEST_OP_DEV_CHECK_CACHE test command
  iommufd/selftest: Add vIOMMU coverage for IOMMU_HWPT_INVALIDATE ioctl
  Documentation: userspace-api: iommufd: Update vDEVICE

 drivers/iommu/iommufd/iommufd_private.h       |  18 ++
 drivers/iommu/iommufd/iommufd_test.h          |  30 +++
 include/linux/iommu.h                         |  48 ++++-
 include/linux/iommufd.h                       |  22 ++
 include/uapi/linux/iommufd.h                  |  31 ++-
 tools/testing/selftests/iommu/iommufd_utils.h |  83 +++++++
 drivers/iommu/iommufd/driver.c                |  13 ++
 drivers/iommu/iommufd/hw_pagetable.c          |  40 +++-
 drivers/iommu/iommufd/main.c                  |   6 +
 drivers/iommu/iommufd/selftest.c              |  98 ++++++++-
 drivers/iommu/iommufd/viommu.c                |  76 +++++++
 tools/testing/selftests/iommu/iommufd.c       | 204 +++++++++++++++++-
 .../selftests/iommu/iommufd_fail_nth.c        |   4 +
 Documentation/userspace-api/iommufd.rst       |  41 +++-
 14 files changed, 688 insertions(+), 26 deletions(-)

-- 
2.43.0

[PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Nicolin Chen]

Introduce a new IOMMUFD_OBJ_VDEVICE to represent a physical device (struct
device) against a vIOMMU (struct iommufd_viommu) object in a VM.

This vDEVICE object (and its structure) holds all the infos and attributes
in the VM, regarding the device related to the vIOMMU.

As an initial patch, add a per-vIOMMU virtual ID. This can be:
 - Virtual StreamID on a nested ARM SMMUv3, an index to a Stream Table
 - Virtual DeviceID on a nested AMD IOMMU, an index to a Device Table
 - Virtual RID on a nested Intel VT-D IOMMU, an index to a Context Table
Potentially, this vDEVICE structure would hold some vData for Confidential
Compute Architecture (CCA). Use this virtual ID to index an "vdevs" xarray
that belongs to a vIOMMU object.

Add a new ioctl for vDEVICE allocations. Since a vDEVICE is a connection
of a device object and an iommufd_viommu object, take two refcounts in the
ioctl handler.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h | 18 ++++++
 include/linux/iommufd.h                 |  4 ++
 include/uapi/linux/iommufd.h            | 22 +++++++
 drivers/iommu/iommufd/main.c            |  6 ++
 drivers/iommu/iommufd/viommu.c          | 76 +++++++++++++++++++++++++
 5 files changed, 126 insertions(+)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index e8f5ef550cc9..062656c19a07 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -507,8 +507,26 @@ static inline int iommufd_hwpt_replace_device(struct iommufd_device *idev,
 	return iommu_group_replace_domain(idev->igroup->group, hwpt->domain);
 }
 
+static inline struct iommufd_viommu *
+iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
+{
+	return container_of(iommufd_get_object(ucmd->ictx, id,
+					       IOMMUFD_OBJ_VIOMMU),
+			    struct iommufd_viommu, obj);
+}
+
 int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
 void iommufd_viommu_destroy(struct iommufd_object *obj);
+int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd);
+void iommufd_vdevice_destroy(struct iommufd_object *obj);
+
+struct iommufd_vdevice {
+	struct iommufd_object obj;
+	struct iommufd_ctx *ictx;
+	struct iommufd_viommu *viommu;
+	struct device *dev;
+	u64 id; /* per-vIOMMU virtual ID */
+};
 
 #ifdef CONFIG_IOMMUFD_TEST
 int iommufd_test(struct iommufd_ucmd *ucmd);
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index f03c75410938..ee58c5c573ec 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -10,6 +10,7 @@
 #include <linux/errno.h>
 #include <linux/refcount.h>
 #include <linux/types.h>
+#include <linux/xarray.h>
 
 struct device;
 struct file;
@@ -31,6 +32,7 @@ enum iommufd_object_type {
 	IOMMUFD_OBJ_ACCESS,
 	IOMMUFD_OBJ_FAULT,
 	IOMMUFD_OBJ_VIOMMU,
+	IOMMUFD_OBJ_VDEVICE,
 #ifdef CONFIG_IOMMUFD_TEST
 	IOMMUFD_OBJ_SELFTEST,
 #endif
@@ -89,6 +91,8 @@ struct iommufd_viommu {
 
 	const struct iommufd_viommu_ops *ops;
 
+	struct xarray vdevs;
+
 	unsigned int type;
 };
 
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index a498d4838f9a..9b5236004b8e 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -53,6 +53,7 @@ enum {
 	IOMMUFD_CMD_FAULT_QUEUE_ALLOC = 0x8e,
 	IOMMUFD_CMD_IOAS_MAP_FILE = 0x8f,
 	IOMMUFD_CMD_VIOMMU_ALLOC = 0x90,
+	IOMMUFD_CMD_VDEVICE_ALLOC = 0x91,
 };
 
 /**
@@ -864,4 +865,25 @@ struct iommu_viommu_alloc {
 	__u32 out_viommu_id;
 };
 #define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)
+
+/**
+ * struct iommu_vdevice_alloc - ioctl(IOMMU_VDEVICE_ALLOC)
+ * @size: sizeof(struct iommu_vdevice_alloc)
+ * @viommu_id: vIOMMU ID to associate with the virtual device
+ * @dev_id: The physical device to allocate a virtual instance on the vIOMMU
+ * @out_vdevice_id: Object handle for the vDevice. Pass to IOMMU_DESTORY
+ * @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
+ *
+ * Allocate a virtual device instance (for a physical device) against a vIOMMU.
+ * This instance holds the device's information (related to its vIOMMU) in a VM.
+ */
+struct iommu_vdevice_alloc {
+	__u32 size;
+	__u32 viommu_id;
+	__u32 dev_id;
+	__u32 out_vdevice_id;
+	__aligned_u64 virt_id;
+};
+#define IOMMU_VDEVICE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VDEVICE_ALLOC)
 #endif
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index cc514f9bc3e6..d735fe04197f 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -308,6 +308,7 @@ union ucmd_buffer {
 	struct iommu_option option;
 	struct iommu_vfio_ioas vfio_ioas;
 	struct iommu_viommu_alloc viommu;
+	struct iommu_vdevice_alloc vdev;
 #ifdef CONFIG_IOMMUFD_TEST
 	struct iommu_test_cmd test;
 #endif
@@ -363,6 +364,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 __reserved),
 	IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
 		 struct iommu_viommu_alloc, out_viommu_id),
+	IOCTL_OP(IOMMU_VDEVICE_ALLOC, iommufd_vdevice_alloc_ioctl,
+		 struct iommu_vdevice_alloc, virt_id),
 #ifdef CONFIG_IOMMUFD_TEST
 	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
@@ -501,6 +504,9 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
 	[IOMMUFD_OBJ_VIOMMU] = {
 		.destroy = iommufd_viommu_destroy,
 	},
+	[IOMMUFD_OBJ_VDEVICE] = {
+		.destroy = iommufd_vdevice_destroy,
+	},
 #ifdef CONFIG_IOMMUFD_TEST
 	[IOMMUFD_OBJ_SELFTEST] = {
 		.destroy = iommufd_selftest_destroy,
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 888239b78667..c82b4a07a4b1 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -11,6 +11,7 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
 	if (viommu->ops && viommu->ops->destroy)
 		viommu->ops->destroy(viommu);
 	refcount_dec(&viommu->hwpt->common.obj.users);
+	xa_destroy(&viommu->vdevs);
 }
 
 int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
@@ -53,6 +54,7 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
 		goto out_put_hwpt;
 	}
 
+	xa_init(&viommu->vdevs);
 	viommu->type = cmd->type;
 	viommu->ictx = ucmd->ictx;
 	viommu->hwpt = hwpt_paging;
@@ -79,3 +81,77 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
 	iommufd_put_object(ucmd->ictx, &idev->obj);
 	return rc;
 }
+
+void iommufd_vdevice_destroy(struct iommufd_object *obj)
+{
+	struct iommufd_vdevice *vdev =
+		container_of(obj, struct iommufd_vdevice, obj);
+	struct iommufd_viommu *viommu = vdev->viommu;
+
+	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
+	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
+	refcount_dec(&viommu->obj.users);
+	put_device(vdev->dev);
+}
+
+int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_vdevice_alloc *cmd = ucmd->cmd;
+	struct iommufd_vdevice *vdev, *curr;
+	struct iommufd_viommu *viommu;
+	struct iommufd_device *idev;
+	u64 virt_id = cmd->virt_id;
+	int rc = 0;
+
+	/* virt_id indexes an xarray */
+	if (virt_id > ULONG_MAX)
+		return -EINVAL;
+
+	viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+	if (IS_ERR(viommu))
+		return PTR_ERR(viommu);
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev)) {
+		rc = PTR_ERR(idev);
+		goto out_put_viommu;
+	}
+
+	if (viommu->iommu_dev != __iommu_get_iommu_dev(idev->dev)) {
+		rc = -EINVAL;
+		goto out_put_idev;
+	}
+
+	vdev = iommufd_object_alloc(ucmd->ictx, vdev, IOMMUFD_OBJ_VDEVICE);
+	if (IS_ERR(vdev)) {
+		rc = PTR_ERR(vdev);
+		goto out_put_idev;
+	}
+
+	vdev->id = virt_id;
+	vdev->dev = idev->dev;
+	get_device(idev->dev);
+	vdev->viommu = viommu;
+	refcount_inc(&viommu->obj.users);
+
+	curr = xa_cmpxchg(&viommu->vdevs, virt_id, NULL, vdev, GFP_KERNEL);
+	if (curr) {
+		rc = xa_err(curr) ?: -EEXIST;
+		goto out_abort;
+	}
+
+	cmd->out_vdevice_id = vdev->obj.id;
+	rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+	if (rc)
+		goto out_abort;
+	iommufd_object_finalize(ucmd->ictx, &vdev->obj);
+	goto out_put_idev;
+
+out_abort:
+	iommufd_object_abort_and_destroy(ucmd->ictx, &vdev->obj);
+out_put_idev:
+	iommufd_put_object(ucmd->ictx, &idev->obj);
+out_put_viommu:
+	iommufd_put_object(ucmd->ictx, &viommu->obj);
+	return rc;
+}
-- 
2.43.0

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Jason Gunthorpe]

On Wed, Oct 30, 2024 at 02:35:27PM -0700, Nicolin Chen wrote:
> +void iommufd_vdevice_destroy(struct iommufd_object *obj)
> +{
> +	struct iommufd_vdevice *vdev =
> +		container_of(obj, struct iommufd_vdevice, obj);
> +	struct iommufd_viommu *viommu = vdev->viommu;
> +
> +	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
> +	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);

There are crazy races that would cause this not to work. Another
thread could have successfully destroyed whatever caused EEXIST and
the successfully registered this same vdev to the same id. Then this
will wrongly erase the other threads entry.

It would be better to skip the erase directly if the EEXIST unwind is
being taken.

Jason

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Nicolin Chen]

On Thu, Oct 31, 2024 at 10:29:41AM -0300, Jason Gunthorpe wrote:
> On Wed, Oct 30, 2024 at 02:35:27PM -0700, Nicolin Chen wrote:
> > +void iommufd_vdevice_destroy(struct iommufd_object *obj)
> > +{
> > +	struct iommufd_vdevice *vdev =
> > +		container_of(obj, struct iommufd_vdevice, obj);
> > +	struct iommufd_viommu *viommu = vdev->viommu;
> > +
> > +	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
> > +	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> 
> There are crazy races that would cause this not to work. Another
> thread could have successfully destroyed whatever caused EEXIST and
> the successfully registered this same vdev to the same id. Then this
> will wrongly erase the other threads entry.
>
> It would be better to skip the erase directly if the EEXIST unwind is
> being taken.

Hmm, is the "another thread" an alloc() or a destroy()? It doesn't
seem to me that there could be another destroy() on the same object
since this current destroy() is the abort to an unfinalized object.
And it doesn't seem that another alloc() will get the same vdev ptr
since every vdev allocation in the alloc() will be different?

That being said, I think we could play safer with the followings:
-------------------------------------------------------------------
@@ -88,7 +88,6 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj)
                container_of(obj, struct iommufd_vdevice, obj);
        struct iommufd_viommu *viommu = vdev->viommu;

-       /* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
        xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
        refcount_dec(&viommu->obj.users);
        put_device(vdev->dev);
@@ -128,18 +127,19 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
                goto out_put_idev;
        }

+       curr = xa_cmpxchg(&viommu->vdevs, virt_id, NULL, vdev, GFP_KERNEL);
+       if (curr) {
+               iommufd_object_abort(ucmd->ictx, &vdev->obj);
+               rc = xa_err(curr) ?: -EEXIST;
+               goto out_put_idev;
+       }
+
        vdev->id = virt_id;
        vdev->dev = idev->dev;
        get_device(idev->dev);
        vdev->viommu = viommu;
        refcount_inc(&viommu->obj.users);

-       curr = xa_cmpxchg(&viommu->vdevs, virt_id, NULL, vdev, GFP_KERNEL);
-       if (curr) {
-               rc = xa_err(curr) ?: -EEXIST;
-               goto out_abort;
-       }
-
        cmd->out_vdevice_id = vdev->obj.id;
        rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
        if (rc)
-------------------------------------------------------------------

Thanks
Nicolin

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Jason Gunthorpe]

On Thu, Oct 31, 2024 at 09:56:37AM -0700, Nicolin Chen wrote:
> On Thu, Oct 31, 2024 at 10:29:41AM -0300, Jason Gunthorpe wrote:
> > On Wed, Oct 30, 2024 at 02:35:27PM -0700, Nicolin Chen wrote:
> > > +void iommufd_vdevice_destroy(struct iommufd_object *obj)
> > > +{
> > > +	struct iommufd_vdevice *vdev =
> > > +		container_of(obj, struct iommufd_vdevice, obj);
> > > +	struct iommufd_viommu *viommu = vdev->viommu;
> > > +
> > > +	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
> > > +	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> > 
> > There are crazy races that would cause this not to work. Another
> > thread could have successfully destroyed whatever caused EEXIST and
> > the successfully registered this same vdev to the same id. Then this
> > will wrongly erase the other threads entry.
> >
> > It would be better to skip the erase directly if the EEXIST unwind is
> > being taken.
>
> Hmm, is the "another thread" an alloc() or a destroy()? 

I was thinking both

> It doesn't seem to me that there could be another destroy() on the
> same object since this current destroy() is the abort to an
> unfinalized object.  And it doesn't seem that another alloc() will
> get the same vdev ptr since every vdev allocation in the alloc()
> will be different?

Ah so you are saying that since the vdev 'old' is local to this thread
it can't possibly by aliased by another?

I was worried the id could be aliased, but yes, that seems right that
the vdev cmpxchg would reject that.

So lets leave it

Jason

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Nicolin Chen]

On Thu, Oct 31, 2024 at 02:04:46PM -0300, Jason Gunthorpe wrote:
> On Thu, Oct 31, 2024 at 09:56:37AM -0700, Nicolin Chen wrote:
> > On Thu, Oct 31, 2024 at 10:29:41AM -0300, Jason Gunthorpe wrote:
> > > On Wed, Oct 30, 2024 at 02:35:27PM -0700, Nicolin Chen wrote:
> > > > +void iommufd_vdevice_destroy(struct iommufd_object *obj)
> > > > +{
> > > > +	struct iommufd_vdevice *vdev =
> > > > +		container_of(obj, struct iommufd_vdevice, obj);
> > > > +	struct iommufd_viommu *viommu = vdev->viommu;
> > > > +
> > > > +	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
> > > > +	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> > > 
> > > There are crazy races that would cause this not to work. Another
> > > thread could have successfully destroyed whatever caused EEXIST and
> > > the successfully registered this same vdev to the same id. Then this
> > > will wrongly erase the other threads entry.
> > >
> > > It would be better to skip the erase directly if the EEXIST unwind is
> > > being taken.
> >
> > Hmm, is the "another thread" an alloc() or a destroy()? 
> 
> I was thinking both
> 
> > It doesn't seem to me that there could be another destroy() on the
> > same object since this current destroy() is the abort to an
> > unfinalized object.  And it doesn't seem that another alloc() will
> > get the same vdev ptr since every vdev allocation in the alloc()
> > will be different?
> 
> Ah so you are saying that since the vdev 'old' is local to this thread
> it can't possibly by aliased by another?
> 
> I was worried the id could be aliased, but yes, that seems right that
> the vdev cmpxchg would reject that.
> 
> So lets leave it

Ack. I'll still update this since xa_cmpxchg can give other errno:
+	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
-	/* xa_cmpxchg is okay to fail if alloc failed xa_cmpxchg previously */

Thanks
Nicolin

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Alexey Kardashevskiy]

On 31/10/24 08:35, Nicolin Chen wrote:
> Introduce a new IOMMUFD_OBJ_VDEVICE to represent a physical device (struct
> device) against a vIOMMU (struct iommufd_viommu) object in a VM.
> 
> This vDEVICE object (and its structure) holds all the infos and attributes
> in the VM, regarding the device related to the vIOMMU.
> 
> As an initial patch, add a per-vIOMMU virtual ID. This can be:
>   - Virtual StreamID on a nested ARM SMMUv3, an index to a Stream Table
>   - Virtual DeviceID on a nested AMD IOMMU, an index to a Device Table
>   - Virtual RID on a nested Intel VT-D IOMMU, an index to a Context Table
> Potentially, this vDEVICE structure would hold some vData for Confidential
> Compute Architecture (CCA). Use this virtual ID to index an "vdevs" xarray
> that belongs to a vIOMMU object.
> 
> Add a new ioctl for vDEVICE allocations. Since a vDEVICE is a connection
> of a device object and an iommufd_viommu object, take two refcounts in the
> ioctl handler.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>   drivers/iommu/iommufd/iommufd_private.h | 18 ++++++
>   include/linux/iommufd.h                 |  4 ++
>   include/uapi/linux/iommufd.h            | 22 +++++++
>   drivers/iommu/iommufd/main.c            |  6 ++
>   drivers/iommu/iommufd/viommu.c          | 76 +++++++++++++++++++++++++
>   5 files changed, 126 insertions(+)
> 
> diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
> index e8f5ef550cc9..062656c19a07 100644
> --- a/drivers/iommu/iommufd/iommufd_private.h
> +++ b/drivers/iommu/iommufd/iommufd_private.h
> @@ -507,8 +507,26 @@ static inline int iommufd_hwpt_replace_device(struct iommufd_device *idev,
>   	return iommu_group_replace_domain(idev->igroup->group, hwpt->domain);
>   }
>   
> +static inline struct iommufd_viommu *
> +iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
> +{
> +	return container_of(iommufd_get_object(ucmd->ictx, id,
> +					       IOMMUFD_OBJ_VIOMMU),
> +			    struct iommufd_viommu, obj);
> +}
> +
>   int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
>   void iommufd_viommu_destroy(struct iommufd_object *obj);
> +int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd);
> +void iommufd_vdevice_destroy(struct iommufd_object *obj);
> +
> +struct iommufd_vdevice {
> +	struct iommufd_object obj;
> +	struct iommufd_ctx *ictx;
> +	struct iommufd_viommu *viommu;
> +	struct device *dev;
> +	u64 id; /* per-vIOMMU virtual ID */
> +};
>   
>   #ifdef CONFIG_IOMMUFD_TEST
>   int iommufd_test(struct iommufd_ucmd *ucmd);
> diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
> index f03c75410938..ee58c5c573ec 100644
> --- a/include/linux/iommufd.h
> +++ b/include/linux/iommufd.h
> @@ -10,6 +10,7 @@
>   #include <linux/errno.h>
>   #include <linux/refcount.h>
>   #include <linux/types.h>
> +#include <linux/xarray.h>
>   
>   struct device;
>   struct file;
> @@ -31,6 +32,7 @@ enum iommufd_object_type {
>   	IOMMUFD_OBJ_ACCESS,
>   	IOMMUFD_OBJ_FAULT,
>   	IOMMUFD_OBJ_VIOMMU,
> +	IOMMUFD_OBJ_VDEVICE,
>   #ifdef CONFIG_IOMMUFD_TEST
>   	IOMMUFD_OBJ_SELFTEST,
>   #endif
> @@ -89,6 +91,8 @@ struct iommufd_viommu {
>   
>   	const struct iommufd_viommu_ops *ops;
>   
> +	struct xarray vdevs;
> +
>   	unsigned int type;
>   };
>   
> diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
> index a498d4838f9a..9b5236004b8e 100644
> --- a/include/uapi/linux/iommufd.h
> +++ b/include/uapi/linux/iommufd.h
> @@ -53,6 +53,7 @@ enum {
>   	IOMMUFD_CMD_FAULT_QUEUE_ALLOC = 0x8e,
>   	IOMMUFD_CMD_IOAS_MAP_FILE = 0x8f,
>   	IOMMUFD_CMD_VIOMMU_ALLOC = 0x90,
> +	IOMMUFD_CMD_VDEVICE_ALLOC = 0x91,
>   };
>   
>   /**
> @@ -864,4 +865,25 @@ struct iommu_viommu_alloc {
>   	__u32 out_viommu_id;
>   };
>   #define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)
> +
> +/**
> + * struct iommu_vdevice_alloc - ioctl(IOMMU_VDEVICE_ALLOC)
> + * @size: sizeof(struct iommu_vdevice_alloc)
> + * @viommu_id: vIOMMU ID to associate with the virtual device
> + * @dev_id: The physical device to allocate a virtual instance on the vIOMMU
> + * @out_vdevice_id: Object handle for the vDevice. Pass to IOMMU_DESTORY
> + * @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


So it is one vdevice per a passed through device (say, a network 
adapter), right? I am asking as there are passed through devices and 
IOMMU devices, and (at least on AMD) IOMMUs look like PCI devices, both 
in hosts and guests. For example, from the above: "@dev_id: The physical 
device ..." - both a network card and IOMMU are physical, so dev_id is a 
NIC or IOMMU? I assume that шы a NIC (but it is a source of constant 
confusion).

Is there any plan to add guest device BDFn as well, or I can add one 
here for my TEE-IO exercise, if it is the right place? It is the same as 
vDeviceID for AMD but I am not sure about the others, hence the 
question. Thanks,


> + *
> + * Allocate a virtual device instance (for a physical device) against a vIOMMU.
> + * This instance holds the device's information (related to its vIOMMU) in a VM.
> + */
> +struct iommu_vdevice_alloc {
> +	__u32 size;
> +	__u32 viommu_id;
> +	__u32 dev_id;
> +	__u32 out_vdevice_id;
> +	__aligned_u64 virt_id;
> +};
> +#define IOMMU_VDEVICE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VDEVICE_ALLOC)
>   #endif
> diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
> index cc514f9bc3e6..d735fe04197f 100644
> --- a/drivers/iommu/iommufd/main.c
> +++ b/drivers/iommu/iommufd/main.c
> @@ -308,6 +308,7 @@ union ucmd_buffer {
>   	struct iommu_option option;
>   	struct iommu_vfio_ioas vfio_ioas;
>   	struct iommu_viommu_alloc viommu;
> +	struct iommu_vdevice_alloc vdev;
>   #ifdef CONFIG_IOMMUFD_TEST
>   	struct iommu_test_cmd test;
>   #endif
> @@ -363,6 +364,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
>   		 __reserved),
>   	IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
>   		 struct iommu_viommu_alloc, out_viommu_id),
> +	IOCTL_OP(IOMMU_VDEVICE_ALLOC, iommufd_vdevice_alloc_ioctl,
> +		 struct iommu_vdevice_alloc, virt_id),
>   #ifdef CONFIG_IOMMUFD_TEST
>   	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
>   #endif
> @@ -501,6 +504,9 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
>   	[IOMMUFD_OBJ_VIOMMU] = {
>   		.destroy = iommufd_viommu_destroy,
>   	},
> +	[IOMMUFD_OBJ_VDEVICE] = {
> +		.destroy = iommufd_vdevice_destroy,
> +	},
>   #ifdef CONFIG_IOMMUFD_TEST
>   	[IOMMUFD_OBJ_SELFTEST] = {
>   		.destroy = iommufd_selftest_destroy,
> diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
> index 888239b78667..c82b4a07a4b1 100644
> --- a/drivers/iommu/iommufd/viommu.c
> +++ b/drivers/iommu/iommufd/viommu.c
> @@ -11,6 +11,7 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
>   	if (viommu->ops && viommu->ops->destroy)
>   		viommu->ops->destroy(viommu);
>   	refcount_dec(&viommu->hwpt->common.obj.users);
> +	xa_destroy(&viommu->vdevs);
>   }
>   
>   int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
> @@ -53,6 +54,7 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
>   		goto out_put_hwpt;
>   	}
>   
> +	xa_init(&viommu->vdevs);
>   	viommu->type = cmd->type;
>   	viommu->ictx = ucmd->ictx;
>   	viommu->hwpt = hwpt_paging;
> @@ -79,3 +81,77 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
>   	iommufd_put_object(ucmd->ictx, &idev->obj);
>   	return rc;
>   }
> +
> +void iommufd_vdevice_destroy(struct iommufd_object *obj)
> +{
> +	struct iommufd_vdevice *vdev =
> +		container_of(obj, struct iommufd_vdevice, obj);
> +	struct iommufd_viommu *viommu = vdev->viommu;
> +
> +	/* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
> +	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> +	refcount_dec(&viommu->obj.users);
> +	put_device(vdev->dev);
> +}
> +
> +int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
> +{
> +	struct iommu_vdevice_alloc *cmd = ucmd->cmd;
> +	struct iommufd_vdevice *vdev, *curr;
> +	struct iommufd_viommu *viommu;
> +	struct iommufd_device *idev;
> +	u64 virt_id = cmd->virt_id;
> +	int rc = 0;
> +
> +	/* virt_id indexes an xarray */
> +	if (virt_id > ULONG_MAX)
> +		return -EINVAL;
> +
> +	viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
> +	if (IS_ERR(viommu))
> +		return PTR_ERR(viommu);
> +
> +	idev = iommufd_get_device(ucmd, cmd->dev_id);
> +	if (IS_ERR(idev)) {
> +		rc = PTR_ERR(idev);
> +		goto out_put_viommu;
> +	}
> +
> +	if (viommu->iommu_dev != __iommu_get_iommu_dev(idev->dev)) {
> +		rc = -EINVAL;
> +		goto out_put_idev;
> +	}
> +
> +	vdev = iommufd_object_alloc(ucmd->ictx, vdev, IOMMUFD_OBJ_VDEVICE);
> +	if (IS_ERR(vdev)) {
> +		rc = PTR_ERR(vdev);
> +		goto out_put_idev;
> +	}
> +
> +	vdev->id = virt_id;
> +	vdev->dev = idev->dev;
> +	get_device(idev->dev);
> +	vdev->viommu = viommu;
> +	refcount_inc(&viommu->obj.users);
> +
> +	curr = xa_cmpxchg(&viommu->vdevs, virt_id, NULL, vdev, GFP_KERNEL);
> +	if (curr) {
> +		rc = xa_err(curr) ?: -EEXIST;
> +		goto out_abort;
> +	}
> +
> +	cmd->out_vdevice_id = vdev->obj.id;
> +	rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
> +	if (rc)
> +		goto out_abort;
> +	iommufd_object_finalize(ucmd->ictx, &vdev->obj);
> +	goto out_put_idev;
> +
> +out_abort:
> +	iommufd_object_abort_and_destroy(ucmd->ictx, &vdev->obj);
> +out_put_idev:
> +	iommufd_put_object(ucmd->ictx, &idev->obj);
> +out_put_viommu:
> +	iommufd_put_object(ucmd->ictx, &viommu->obj);
> +	return rc;
> +}

-- 
Alexey

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Nicolin Chen]

On Thu, Nov 07, 2024 at 09:11:27PM +1100, Alexey Kardashevskiy wrote:
> On 31/10/24 08:35, Nicolin Chen wrote:
> > Introduce a new IOMMUFD_OBJ_VDEVICE to represent a physical device (struct
> > device) against a vIOMMU (struct iommufd_viommu) object in a VM.
> > 
> > This vDEVICE object (and its structure) holds all the infos and attributes
> > in the VM, regarding the device related to the vIOMMU.
> > 
> > As an initial patch, add a per-vIOMMU virtual ID. This can be:
> >   - Virtual StreamID on a nested ARM SMMUv3, an index to a Stream Table
> >   - Virtual DeviceID on a nested AMD IOMMU, an index to a Device Table
> >   - Virtual RID on a nested Intel VT-D IOMMU, an index to a Context Table
> > Potentially, this vDEVICE structure would hold some vData for Confidential
> > Compute Architecture (CCA). Use this virtual ID to index an "vdevs" xarray
> > that belongs to a vIOMMU object.
> > 
> > Add a new ioctl for vDEVICE allocations. Since a vDEVICE is a connection
> > of a device object and an iommufd_viommu object, take two refcounts in the
> > ioctl handler.

> > +/**
> > + * struct iommu_vdevice_alloc - ioctl(IOMMU_VDEVICE_ALLOC)
> > + * @size: sizeof(struct iommu_vdevice_alloc)
> > + * @viommu_id: vIOMMU ID to associate with the virtual device
> > + * @dev_id: The physical device to allocate a virtual instance on the vIOMMU
> > + * @out_vdevice_id: Object handle for the vDevice. Pass to IOMMU_DESTORY
> > + * @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
> 
> 
> So it is one vdevice per a passed through device (say, a network
> adapter), right?

Yes. It's per iommufd_device per iommufd_viommu.

> I am asking as there are passed through devices and
> IOMMU devices, and (at least on AMD) IOMMUs look like PCI devices, both
> in hosts and guests. For example, from the above: "@dev_id: The physical
> device ..." - both a network card and IOMMU are physical, so dev_id is a
> NIC or IOMMU? I assume that шы a NIC (but it is a source of constant
> confusion).

In that case, dev_id is NIC. viommu_id is IOMMU.

First VMM should allocate a vIOMMU using the dev_id (NIC) to get
a viommu_id, and then use this viommu_id and dev_id to allocate
a vDEVICE.

It might sound duplicated in this case because this AMD IOMMU is
exclusive for the NIC. But ARM/Intel can be shared among devices
so they can allocate a vIOMMU with device1 and allocate vDEVICEs
for device1, device2, device3, and so on.

> Is there any plan to add guest device BDFn as well, or I can add one
> here for my TEE-IO exercise, if it is the right place? It is the same as
> vDeviceID for AMD but I am not sure about the others, hence the
> question. Thanks,

Generally speaking, adding vRID isn't a problem so long as there
is a legit reason/usecase. That being said, if it is the same as
the @virt_id for AMD, why not just pass via @virt_id v.s. adding
a new vRID/vBDF field?

Thanks
Nicolin

Re: [PATCH v6 01/10] iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl

[Jason Gunthorpe]

On Thu, Nov 07, 2024 at 08:31:39AM -0800, Nicolin Chen wrote:
> > Is there any plan to add guest device BDFn as well, or I can add one
> > here for my TEE-IO exercise, if it is the right place? It is the same as
> > vDeviceID for AMD but I am not sure about the others, hence the
> > question. Thanks,
> 
> Generally speaking, adding vRID isn't a problem so long as there
> is a legit reason/usecase. That being said, if it is the same as
> the @virt_id for AMD, why not just pass via @virt_id v.s. adding
> a new vRID/vBDF field?

For CC I'm expecting you to add a AMD CC specific datablob to alloc
viommu that convays all the specific details that the CC world needs
to define the vPCI device. This might include vRID

It depends how you define vdeviceid - for AMD vdeviceid is the index
into the DTE table. vRID, especially if it includes a segment id may
be a larger value and should be seperate.

Jason

[PATCH v6 02/10] iommufd/selftest: Add IOMMU_VDEVICE_ALLOC test coverage

[Nicolin Chen]

Add a vdevice_alloc op to the viommu mock_viommu_ops for the coverage of
IOMMU_VIOMMU_TYPE_SELFTEST allocations. Then, add a vdevice_alloc TEST_F
to cover the IOMMU_VDEVICE_ALLOC ioctl.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 tools/testing/selftests/iommu/iommufd_utils.h | 27 +++++++++++++++++++
 tools/testing/selftests/iommu/iommufd.c       | 20 ++++++++++++++
 .../selftests/iommu/iommufd_fail_nth.c        |  4 +++
 3 files changed, 51 insertions(+)

diff --git a/tools/testing/selftests/iommu/iommufd_utils.h b/tools/testing/selftests/iommu/iommufd_utils.h
index 7dabc261fae2..7fe905924d72 100644
--- a/tools/testing/selftests/iommu/iommufd_utils.h
+++ b/tools/testing/selftests/iommu/iommufd_utils.h
@@ -847,3 +847,30 @@ static int _test_cmd_viommu_alloc(int fd, __u32 device_id, __u32 hwpt_id,
 	EXPECT_ERRNO(_errno,                                               \
 		     _test_cmd_viommu_alloc(self->fd, device_id, hwpt_id,  \
 					    type, 0, viommu_id))
+
+static int _test_cmd_vdevice_alloc(int fd, __u32 viommu_id, __u32 idev_id,
+				   __u64 virt_id, __u32 *vdev_id)
+{
+	struct iommu_vdevice_alloc cmd = {
+		.size = sizeof(cmd),
+		.dev_id = idev_id,
+		.viommu_id = viommu_id,
+		.virt_id = virt_id,
+	};
+	int ret;
+
+	ret = ioctl(fd, IOMMU_VDEVICE_ALLOC, &cmd);
+	if (ret)
+		return ret;
+	if (vdev_id)
+		*vdev_id = cmd.out_vdevice_id;
+	return 0;
+}
+
+#define test_cmd_vdevice_alloc(viommu_id, idev_id, virt_id, vdev_id)       \
+	ASSERT_EQ(0, _test_cmd_vdevice_alloc(self->fd, viommu_id, idev_id, \
+					     virt_id, vdev_id))
+#define test_err_vdevice_alloc(_errno, viommu_id, idev_id, virt_id, vdev_id) \
+	EXPECT_ERRNO(_errno,                                                 \
+		     _test_cmd_vdevice_alloc(self->fd, viommu_id, idev_id,   \
+					     virt_id, vdev_id))
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index 3142819cc26d..2610117cb39e 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -134,6 +134,7 @@ TEST_F(iommufd, cmd_length)
 	TEST_LENGTH(iommu_vfio_ioas, IOMMU_VFIO_IOAS, __reserved);
 	TEST_LENGTH(iommu_ioas_map_file, IOMMU_IOAS_MAP_FILE, iova);
 	TEST_LENGTH(iommu_viommu_alloc, IOMMU_VIOMMU_ALLOC, out_viommu_id);
+	TEST_LENGTH(iommu_vdevice_alloc, IOMMU_VDEVICE_ALLOC, virt_id);
 #undef TEST_LENGTH
 }
 
@@ -2608,4 +2609,23 @@ TEST_F(iommufd_viommu, viommu_alloc_nested_iopf)
 	}
 }
 
+TEST_F(iommufd_viommu, vdevice_alloc)
+{
+	uint32_t viommu_id = self->viommu_id;
+	uint32_t dev_id = self->device_id;
+	uint32_t vdev_id = 0;
+
+	if (dev_id) {
+		/* Set vdev_id to 0x99, unset it, and set to 0x88 */
+		test_cmd_vdevice_alloc(viommu_id, dev_id, 0x99, &vdev_id);
+		test_err_vdevice_alloc(EEXIST, viommu_id, dev_id, 0x99,
+				       &vdev_id);
+		test_ioctl_destroy(vdev_id);
+		test_cmd_vdevice_alloc(viommu_id, dev_id, 0x88, &vdev_id);
+		test_ioctl_destroy(vdev_id);
+	} else {
+		test_err_vdevice_alloc(ENOENT, viommu_id, dev_id, 0x99, NULL);
+	}
+}
+
 TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/iommu/iommufd_fail_nth.c b/tools/testing/selftests/iommu/iommufd_fail_nth.c
index fb618485d7ca..22f6fd5f0f74 100644
--- a/tools/testing/selftests/iommu/iommufd_fail_nth.c
+++ b/tools/testing/selftests/iommu/iommufd_fail_nth.c
@@ -622,6 +622,7 @@ TEST_FAIL_NTH(basic_fail_nth, device)
 	uint32_t idev_id;
 	uint32_t hwpt_id;
 	uint32_t viommu_id;
+	uint32_t vdev_id;
 	__u64 iova;
 
 	self->fd = open("/dev/iommu", O_RDWR);
@@ -674,6 +675,9 @@ TEST_FAIL_NTH(basic_fail_nth, device)
 				   IOMMU_VIOMMU_TYPE_SELFTEST, 0, &viommu_id))
 		return -1;
 
+	if (_test_cmd_vdevice_alloc(self->fd, viommu_id, idev_id, 0, &vdev_id))
+		return -1;
+
 	return 0;
 }
 
-- 
2.43.0

[PATCH v6 03/10] iommu/viommu: Add cache_invalidate to iommufd_viommu_ops

[Nicolin Chen]

This per-vIOMMU cache_invalidate op is like the cache_invalidate_user op
in struct iommu_domain_ops, but wider, supporting device cache (e.g. PCI
ATC invaldiations).

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 include/linux/iommufd.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index ee58c5c573ec..4e59af87a524 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -16,6 +16,7 @@ struct device;
 struct file;
 struct iommu_group;
 struct iommu_user_data;
+struct iommu_user_data_array;
 struct iommufd_access;
 struct iommufd_ctx;
 struct iommufd_device;
@@ -105,12 +106,21 @@ struct iommufd_viommu {
  *                       must be defined in include/uapi/linux/iommufd.h.
  *                       It must fully initialize the new iommu_domain before
  *                       returning. Upon failure, ERR_PTR must be returned.
+ * @cache_invalidate: Flush hardware cache used by a vIOMMU. It can be used for
+ *                    any IOMMU hardware specific cache: TLB and device cache.
+ *                    The @array passes in the cache invalidation requests, in
+ *                    form of a driver data structure. A driver must update the
+ *                    array->entry_num to report the number of handled requests.
+ *                    The data structure of the array entry must be defined in
+ *                    include/uapi/linux/iommufd.h
  */
 struct iommufd_viommu_ops {
 	void (*destroy)(struct iommufd_viommu *viommu);
 	struct iommu_domain *(*alloc_domain_nested)(
 		struct iommufd_viommu *viommu, u32 flags,
 		const struct iommu_user_data *user_data);
+	int (*cache_invalidate)(struct iommufd_viommu *viommu,
+				struct iommu_user_data_array *array);
 };
 
 #if IS_ENABLED(CONFIG_IOMMUFD)
-- 
2.43.0

[PATCH v6 04/10] iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE

[Nicolin Chen]

With a vIOMMU object, use space can flush any IOMMU related cache that can
be directed via a vIOMMU object. It is similar to the IOMMU_HWPT_INVALIDATE
uAPI, but can cover a wider range than IOTLB, e.g. device/desciprtor cache.

Allow hwpt_id of the iommu_hwpt_invalidate structure to carry a viommu_id,
and reuse the IOMMU_HWPT_INVALIDATE uAPI for vIOMMU invalidations. Drivers
can define different structures for vIOMMU invalidations v.s. HWPT ones.

Since both the HWPT-based and vIOMMU-based invalidation pathways check own
cache invalidation op, remove the WARN_ON_ONCE in the allocator.

Update the uAPI, kdoc, and selftest case accordingly.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 include/uapi/linux/iommufd.h            |  9 ++++--
 drivers/iommu/iommufd/hw_pagetable.c    | 40 +++++++++++++++++++------
 tools/testing/selftests/iommu/iommufd.c |  4 +--
 3 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 9b5236004b8e..badb41c5bfa4 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -700,7 +700,7 @@ struct iommu_hwpt_vtd_s1_invalidate {
 /**
  * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
  * @size: sizeof(struct iommu_hwpt_invalidate)
- * @hwpt_id: ID of a nested HWPT for cache invalidation
+ * @hwpt_id: ID of a nested HWPT or a vIOMMU, for cache invalidation
  * @data_uptr: User pointer to an array of driver-specific cache invalidation
  *             data.
  * @data_type: One of enum iommu_hwpt_invalidate_data_type, defining the data
@@ -711,8 +711,11 @@ struct iommu_hwpt_vtd_s1_invalidate {
  *             Output the number of requests successfully handled by kernel.
  * @__reserved: Must be 0.
  *
- * Invalidate the iommu cache for user-managed page table. Modifications on a
- * user-managed page table should be followed by this operation to sync cache.
+ * Invalidate iommu cache for user-managed page table or vIOMMU. Modifications
+ * on a user-managed page table should be followed by this operation, if a HWPT
+ * is passed in via @hwpt_id. Other caches, such as device cache or descriptor
+ * cache can be flushed if a vIOMMU is passed in via the @hwpt_id field.
+ *
  * Each ioctl can support one or more cache invalidation requests in the array
  * that has a total size of @entry_len * @entry_num.
  *
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 384afa374d25..d8f8b0642a26 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -251,8 +251,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 	}
 	hwpt->domain->owner = ops;
 
-	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED ||
-			 !hwpt->domain->ops->cache_invalidate_user)) {
+	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED)) {
 		rc = -EINVAL;
 		goto out_abort;
 	}
@@ -482,7 +481,7 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
 		.entry_len = cmd->entry_len,
 		.entry_num = cmd->entry_num,
 	};
-	struct iommufd_hw_pagetable *hwpt;
+	struct iommufd_object *pt_obj;
 	u32 done_num = 0;
 	int rc;
 
@@ -496,17 +495,40 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
 		goto out;
 	}
 
-	hwpt = iommufd_get_hwpt_nested(ucmd, cmd->hwpt_id);
-	if (IS_ERR(hwpt)) {
-		rc = PTR_ERR(hwpt);
+	pt_obj = iommufd_get_object(ucmd->ictx, cmd->hwpt_id, IOMMUFD_OBJ_ANY);
+	if (IS_ERR(pt_obj)) {
+		rc = PTR_ERR(pt_obj);
 		goto out;
 	}
+	if (pt_obj->type == IOMMUFD_OBJ_HWPT_NESTED) {
+		struct iommufd_hw_pagetable *hwpt =
+			container_of(pt_obj, struct iommufd_hw_pagetable, obj);
+
+		if (!hwpt->domain->ops ||
+		    !hwpt->domain->ops->cache_invalidate_user) {
+			rc = -EOPNOTSUPP;
+			goto out_put_pt;
+		}
+		rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
+							      &data_array);
+	} else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {
+		struct iommufd_viommu *viommu =
+			container_of(pt_obj, struct iommufd_viommu, obj);
+
+		if (!viommu->ops || !viommu->ops->cache_invalidate) {
+			rc = -EOPNOTSUPP;
+			goto out_put_pt;
+		}
+		rc = viommu->ops->cache_invalidate(viommu, &data_array);
+	} else {
+		rc = -EINVAL;
+		goto out_put_pt;
+	}
 
-	rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
-						      &data_array);
 	done_num = data_array.entry_num;
 
-	iommufd_put_object(ucmd->ictx, &hwpt->obj);
+out_put_pt:
+	iommufd_put_object(ucmd->ictx, pt_obj);
 out:
 	cmd->entry_num = done_num;
 	if (iommufd_ucmd_respond(ucmd, sizeof(*cmd)))
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index 2610117cb39e..c47ad6502efc 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -367,9 +367,9 @@ TEST_F(iommufd_ioas, alloc_hwpt_nested)
 		EXPECT_ERRNO(EBUSY,
 			     _test_ioctl_destroy(self->fd, parent_hwpt_id));
 
-		/* hwpt_invalidate only supports a user-managed hwpt (nested) */
+		/* hwpt_invalidate does not support a parent hwpt */
 		num_inv = 1;
-		test_err_hwpt_invalidate(ENOENT, parent_hwpt_id, inv_reqs,
+		test_err_hwpt_invalidate(EINVAL, parent_hwpt_id, inv_reqs,
 					 IOMMU_HWPT_INVALIDATE_DATA_SELFTEST,
 					 sizeof(*inv_reqs), &num_inv);
 		assert(!num_inv);
-- 
2.43.0

[PATCH v6 05/10] iommu: Add iommu_copy_struct_from_full_user_array helper

[Nicolin Chen]

From: Jason Gunthorpe <jgg@nvidia.com>

The iommu_copy_struct_from_user_array helper can be used to copy a single
entry from a user array which might not be efficient if the array is big.

Add a new iommu_copy_struct_from_full_user_array to copy the entire user
array at once. Update the existing iommu_copy_struct_from_user_array kdoc
accordingly.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 include/linux/iommu.h | 48 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2574fc8abaf2..11de66237eaa 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -493,7 +493,9 @@ static inline int __iommu_copy_struct_from_user_array(
  * @index: Index to the location in the array to copy user data from
  * @min_last: The last member of the data structure @kdst points in the
  *            initial version.
- * Return 0 for success, otherwise -error.
+ *
+ * Copy a single entry from a user array. Return 0 for success, otherwise
+ * -error.
  */
 #define iommu_copy_struct_from_user_array(kdst, user_array, data_type, index, \
 					  min_last)                           \
@@ -501,6 +503,50 @@ static inline int __iommu_copy_struct_from_user_array(
 		kdst, user_array, data_type, index, sizeof(*(kdst)),          \
 		offsetofend(typeof(*(kdst)), min_last))
 
+/**
+ * iommu_copy_struct_from_full_user_array - Copy iommu driver specific user
+ *         space data from an iommu_user_data_array
+ * @kdst: Pointer to an iommu driver specific user data that is defined in
+ *        include/uapi/linux/iommufd.h
+ * @kdst_entry_size: sizeof(*kdst)
+ * @user_array: Pointer to a struct iommu_user_data_array for a user space
+ *              array
+ * @data_type: The data type of the @kdst. Must match with @user_array->type
+ *
+ * Copy the entire user array. kdst must have room for kdst_entry_size *
+ * user_array->entry_num bytes. Return 0 for success, otherwise -error.
+ */
+static inline int
+iommu_copy_struct_from_full_user_array(void *kdst, size_t kdst_entry_size,
+				       struct iommu_user_data_array *user_array,
+				       unsigned int data_type)
+{
+	unsigned int i;
+	int ret;
+
+	if (user_array->type != data_type)
+		return -EINVAL;
+	if (!user_array->entry_num)
+		return -EINVAL;
+	if (likely(user_array->entry_len == kdst_entry_size)) {
+		if (copy_from_user(kdst, user_array->uptr,
+				   user_array->entry_num *
+					   user_array->entry_len))
+			return -EFAULT;
+	}
+
+	/* Copy item by item */
+	for (i = 0; i != user_array->entry_num; i++) {
+		ret = copy_struct_from_user(
+			kdst + kdst_entry_size * i, kdst_entry_size,
+			user_array->uptr + user_array->entry_len * i,
+			user_array->entry_len);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
 /**
  * struct iommu_ops - iommu ops and capabilities
  * @capable: check capability
-- 
2.43.0

Re: [PATCH v6 05/10] iommu: Add iommu_copy_struct_from_full_user_array helper

[Jason Gunthorpe]

On Wed, Oct 30, 2024 at 02:35:31PM -0700, Nicolin Chen wrote:
> From: Jason Gunthorpe <jgg@nvidia.com>
> 
> The iommu_copy_struct_from_user_array helper can be used to copy a single
> entry from a user array which might not be efficient if the array is big.
> 
> Add a new iommu_copy_struct_from_full_user_array to copy the entire user
> array at once. Update the existing iommu_copy_struct_from_user_array kdoc
> accordingly.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  include/linux/iommu.h | 48 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 47 insertions(+), 1 deletion(-)

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

Jason

[PATCH v6 06/10] iommufd/viommu: Add iommufd_viommu_find_dev helper

[Nicolin Chen]

This avoids a bigger trouble of exposing struct iommufd_device and struct
iommufd_vdevice in the public header.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 include/linux/iommufd.h        |  8 ++++++++
 drivers/iommu/iommufd/driver.c | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 4e59af87a524..d263bd9fca6b 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -142,6 +142,8 @@ int iommufd_vfio_compat_set_no_iommu(struct iommufd_ctx *ictx);
 struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
 					     size_t size,
 					     enum iommufd_object_type type);
+struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
+				       unsigned long vdev_id);
 #else /* !CONFIG_IOMMUFD */
 static inline struct iommufd_ctx *iommufd_ctx_from_file(struct file *file)
 {
@@ -189,6 +191,12 @@ _iommufd_object_alloc(struct iommufd_ctx *ictx, size_t size,
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+
+static inline struct device *
+iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id)
+{
+	return NULL;
+}
 #endif /* CONFIG_IOMMUFD */
 
 /*
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 2bc47d92a0ab..7b67fdf44134 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -36,5 +36,18 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
 }
 EXPORT_SYMBOL_NS_GPL(_iommufd_object_alloc, IOMMUFD);
 
+/* Caller should xa_lock(&viommu->vdevs) to protect the return value */
+struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
+				       unsigned long vdev_id)
+{
+	struct iommufd_vdevice *vdev;
+
+	lockdep_assert_held(&viommu->vdevs.xa_lock);
+
+	vdev = xa_load(&viommu->vdevs, vdev_id);
+	return vdev ? vdev->dev : NULL;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, IOMMUFD);
+
 MODULE_DESCRIPTION("iommufd code shared with builtin modules");
 MODULE_LICENSE("GPL");
-- 
2.43.0

Re: [PATCH v6 06/10] iommufd/viommu: Add iommufd_viommu_find_dev helper

[Jason Gunthorpe]

On Wed, Oct 30, 2024 at 02:35:32PM -0700, Nicolin Chen wrote:
> This avoids a bigger trouble of exposing struct iommufd_device and struct
> iommufd_vdevice in the public header.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  include/linux/iommufd.h        |  8 ++++++++
>  drivers/iommu/iommufd/driver.c | 13 +++++++++++++
>  2 files changed, 21 insertions(+)

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

Jason

[PATCH v6 07/10] iommufd/selftest: Add mock_viommu_cache_invalidate

[Nicolin Chen]

Similar to the coverage of cache_invalidate_user for iotlb invalidation,
add a device cache and a viommu_cache_invalidate function to test it out.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_test.h | 25 +++++++++
 drivers/iommu/iommufd/selftest.c     | 76 +++++++++++++++++++++++++++-
 2 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/iommufd_test.h b/drivers/iommu/iommufd/iommufd_test.h
index edced4ac7cd3..46558f83e734 100644
--- a/drivers/iommu/iommufd/iommufd_test.h
+++ b/drivers/iommu/iommufd/iommufd_test.h
@@ -54,6 +54,11 @@ enum {
 	MOCK_NESTED_DOMAIN_IOTLB_NUM = 4,
 };
 
+enum {
+	MOCK_DEV_CACHE_ID_MAX = 3,
+	MOCK_DEV_CACHE_NUM = 4,
+};
+
 struct iommu_test_cmd {
 	__u32 size;
 	__u32 op;
@@ -152,6 +157,7 @@ struct iommu_test_hw_info {
 /* Should not be equal to any defined value in enum iommu_hwpt_data_type */
 #define IOMMU_HWPT_DATA_SELFTEST 0xdead
 #define IOMMU_TEST_IOTLB_DEFAULT 0xbadbeef
+#define IOMMU_TEST_DEV_CACHE_DEFAULT 0xbaddad
 
 /**
  * struct iommu_hwpt_selftest
@@ -182,4 +188,23 @@ struct iommu_hwpt_invalidate_selftest {
 
 #define IOMMU_VIOMMU_TYPE_SELFTEST 0xdeadbeef
 
+/* Should not be equal to any defined value in enum iommu_viommu_invalidate_data_type */
+#define IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST 0xdeadbeef
+#define IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST_INVALID 0xdadbeef
+
+/**
+ * struct iommu_viommu_invalidate_selftest - Invalidation data for Mock VIOMMU
+ *                                        (IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST)
+ * @flags: Invalidate flags
+ * @cache_id: Invalidate cache entry index
+ *
+ * If IOMMU_TEST_INVALIDATE_ALL is set in @flags, @cache_id will be ignored
+ */
+struct iommu_viommu_invalidate_selftest {
+#define IOMMU_TEST_INVALIDATE_FLAG_ALL (1 << 0)
+	__u32 flags;
+	__u32 vdev_id;
+	__u32 cache_id;
+};
+
 #endif
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 31c8f78a3a66..e20498667a2c 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -163,6 +163,7 @@ struct mock_dev {
 	struct device dev;
 	unsigned long flags;
 	int id;
+	u32 cache[MOCK_DEV_CACHE_NUM];
 };
 
 static inline struct mock_dev *to_mock_dev(struct device *dev)
@@ -609,9 +610,80 @@ mock_viommu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
 	return &mock_nested->domain;
 }
 
+static int mock_viommu_cache_invalidate(struct iommufd_viommu *viommu,
+					struct iommu_user_data_array *array)
+{
+	struct iommu_viommu_invalidate_selftest *cmds;
+	struct iommu_viommu_invalidate_selftest *cur;
+	struct iommu_viommu_invalidate_selftest *end;
+	int rc;
+
+	/* A zero-length array is allowed to validate the array type */
+	if (array->entry_num == 0 &&
+	    array->type == IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST) {
+		array->entry_num = 0;
+		return 0;
+	}
+
+	cmds = kcalloc(array->entry_num, sizeof(*cmds), GFP_KERNEL);
+	if (!cmds)
+		return -ENOMEM;
+	cur = cmds;
+	end = cmds + array->entry_num;
+
+	static_assert(sizeof(*cmds) == 3 * sizeof(u32));
+	rc = iommu_copy_struct_from_full_user_array(
+		cmds, sizeof(*cmds), array,
+		IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST);
+	if (rc)
+		goto out;
+
+	while (cur != end) {
+		struct mock_dev *mdev;
+		struct device *dev;
+		int i;
+
+		if (cur->flags & ~IOMMU_TEST_INVALIDATE_FLAG_ALL) {
+			rc = -EOPNOTSUPP;
+			goto out;
+		}
+
+		if (cur->cache_id > MOCK_DEV_CACHE_ID_MAX) {
+			rc = -EINVAL;
+			goto out;
+		}
+
+		xa_lock(&viommu->vdevs);
+		dev = iommufd_viommu_find_dev(viommu,
+					      (unsigned long)cur->vdev_id);
+		if (!dev) {
+			xa_unlock(&viommu->vdevs);
+			rc = -EINVAL;
+			goto out;
+		}
+		mdev = container_of(dev, struct mock_dev, dev);
+
+		if (cur->flags & IOMMU_TEST_INVALIDATE_FLAG_ALL) {
+			/* Invalidate all cache entries and ignore cache_id */
+			for (i = 0; i < MOCK_DEV_CACHE_NUM; i++)
+				mdev->cache[i] = 0;
+		} else {
+			mdev->cache[cur->cache_id] = 0;
+		}
+		xa_unlock(&viommu->vdevs);
+
+		cur++;
+	}
+out:
+	array->entry_num = cur - cmds;
+	kfree(cmds);
+	return rc;
+}
+
 static struct iommufd_viommu_ops mock_viommu_ops = {
 	.destroy = mock_viommu_destroy,
 	.alloc_domain_nested = mock_viommu_alloc_domain_nested,
+	.cache_invalidate = mock_viommu_cache_invalidate,
 };
 
 static struct iommufd_viommu *mock_viommu_alloc(struct device *dev,
@@ -782,7 +854,7 @@ static void mock_dev_release(struct device *dev)
 static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 {
 	struct mock_dev *mdev;
-	int rc;
+	int rc, i;
 
 	if (dev_flags &
 	    ~(MOCK_FLAGS_DEVICE_NO_DIRTY | MOCK_FLAGS_DEVICE_HUGE_IOVA))
@@ -796,6 +868,8 @@ static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 	mdev->flags = dev_flags;
 	mdev->dev.release = mock_dev_release;
 	mdev->dev.bus = &iommufd_mock_bus_type.bus;
+	for (i = 0; i < MOCK_DEV_CACHE_NUM; i++)
+		mdev->cache[i] = IOMMU_TEST_DEV_CACHE_DEFAULT;
 
 	rc = ida_alloc(&mock_dev_ida, GFP_KERNEL);
 	if (rc < 0)
-- 
2.43.0

[PATCH v6 08/10] iommufd/selftest: Add IOMMU_TEST_OP_DEV_CHECK_CACHE test command

[Nicolin Chen]

Similar to IOMMU_TEST_OP_MD_CHECK_IOTLB verifying a mock_domain's iotlb,
IOMMU_TEST_OP_DEV_CHECK_CACHE will be used to verify a mock_dev's cache.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_test.h          |  5 ++++
 tools/testing/selftests/iommu/iommufd_utils.h | 24 +++++++++++++++++++
 drivers/iommu/iommufd/selftest.c              | 22 +++++++++++++++++
 tools/testing/selftests/iommu/iommufd.c       |  7 +++++-
 4 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/iommufd_test.h b/drivers/iommu/iommufd/iommufd_test.h
index 46558f83e734..a6b7a163f636 100644
--- a/drivers/iommu/iommufd/iommufd_test.h
+++ b/drivers/iommu/iommufd/iommufd_test.h
@@ -23,6 +23,7 @@ enum {
 	IOMMU_TEST_OP_DIRTY,
 	IOMMU_TEST_OP_MD_CHECK_IOTLB,
 	IOMMU_TEST_OP_TRIGGER_IOPF,
+	IOMMU_TEST_OP_DEV_CHECK_CACHE,
 };
 
 enum {
@@ -140,6 +141,10 @@ struct iommu_test_cmd {
 			__u32 perm;
 			__u64 addr;
 		} trigger_iopf;
+		struct {
+			__u32 id;
+			__u32 cache;
+		} check_dev_cache;
 	};
 	__u32 last;
 };
diff --git a/tools/testing/selftests/iommu/iommufd_utils.h b/tools/testing/selftests/iommu/iommufd_utils.h
index 7fe905924d72..619ffdb1e5e8 100644
--- a/tools/testing/selftests/iommu/iommufd_utils.h
+++ b/tools/testing/selftests/iommu/iommufd_utils.h
@@ -250,6 +250,30 @@ static int _test_cmd_hwpt_alloc(int fd, __u32 device_id, __u32 pt_id, __u32 ft_i
 			test_cmd_hwpt_check_iotlb(hwpt_id, i, expected);       \
 	})
 
+#define test_cmd_dev_check_cache(device_id, cache_id, expected)                \
+	({                                                                     \
+		struct iommu_test_cmd test_cmd = {                             \
+			.size = sizeof(test_cmd),                              \
+			.op = IOMMU_TEST_OP_DEV_CHECK_CACHE,                   \
+			.id = device_id,                                       \
+			.check_dev_cache = {                                   \
+				.id = cache_id,                                \
+				.cache = expected,                             \
+			},                                                     \
+		};                                                             \
+		ASSERT_EQ(0, ioctl(self->fd,                                   \
+				   _IOMMU_TEST_CMD(                            \
+					   IOMMU_TEST_OP_DEV_CHECK_CACHE),     \
+				   &test_cmd));                                \
+	})
+
+#define test_cmd_dev_check_cache_all(device_id, expected)                      \
+	({                                                                     \
+		int c;                                                         \
+		for (c = 0; c < MOCK_DEV_CACHE_NUM; c++)                       \
+			test_cmd_dev_check_cache(device_id, c, expected);      \
+	})
+
 static int _test_cmd_hwpt_invalidate(int fd, __u32 hwpt_id, void *reqs,
 				     uint32_t data_type, uint32_t lreq,
 				     uint32_t *nreqs)
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index e20498667a2c..2f9de177dffc 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -1125,6 +1125,24 @@ static int iommufd_test_md_check_iotlb(struct iommufd_ucmd *ucmd,
 	return rc;
 }
 
+static int iommufd_test_dev_check_cache(struct iommufd_ucmd *ucmd, u32 idev_id,
+					unsigned int cache_id, u32 cache)
+{
+	struct iommufd_device *idev;
+	struct mock_dev *mdev;
+	int rc = 0;
+
+	idev = iommufd_get_device(ucmd, idev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+	mdev = container_of(idev->dev, struct mock_dev, dev);
+
+	if (cache_id > MOCK_DEV_CACHE_ID_MAX || mdev->cache[cache_id] != cache)
+		rc = -EINVAL;
+	iommufd_put_object(ucmd->ictx, &idev->obj);
+	return rc;
+}
+
 struct selftest_access {
 	struct iommufd_access *access;
 	struct file *file;
@@ -1634,6 +1652,10 @@ int iommufd_test(struct iommufd_ucmd *ucmd)
 		return iommufd_test_md_check_iotlb(ucmd, cmd->id,
 						   cmd->check_iotlb.id,
 						   cmd->check_iotlb.iotlb);
+	case IOMMU_TEST_OP_DEV_CHECK_CACHE:
+		return iommufd_test_dev_check_cache(ucmd, cmd->id,
+						    cmd->check_dev_cache.id,
+						    cmd->check_dev_cache.cache);
 	case IOMMU_TEST_OP_CREATE_ACCESS:
 		return iommufd_test_create_access(ucmd, cmd->id,
 						  cmd->create_access.flags);
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index c47ad6502efc..54f3b81e5479 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -227,6 +227,8 @@ FIXTURE_SETUP(iommufd_ioas)
 	for (i = 0; i != variant->mock_domains; i++) {
 		test_cmd_mock_domain(self->ioas_id, &self->stdev_id,
 				     &self->hwpt_id, &self->device_id);
+		test_cmd_dev_check_cache_all(self->device_id,
+					     IOMMU_TEST_DEV_CACHE_DEFAULT);
 		self->base_iova = MOCK_APERTURE_START;
 	}
 }
@@ -1392,9 +1394,12 @@ FIXTURE_SETUP(iommufd_mock_domain)
 
 	ASSERT_GE(ARRAY_SIZE(self->hwpt_ids), variant->mock_domains);
 
-	for (i = 0; i != variant->mock_domains; i++)
+	for (i = 0; i != variant->mock_domains; i++) {
 		test_cmd_mock_domain(self->ioas_id, &self->stdev_ids[i],
 				     &self->hwpt_ids[i], &self->idev_ids[i]);
+		test_cmd_dev_check_cache_all(self->idev_ids[0],
+					     IOMMU_TEST_DEV_CACHE_DEFAULT);
+	}
 	self->hwpt_id = self->hwpt_ids[0];
 
 	self->mmap_flags = MAP_SHARED | MAP_ANONYMOUS;
-- 
2.43.0

Re: [PATCH v6 08/10] iommufd/selftest: Add IOMMU_TEST_OP_DEV_CHECK_CACHE test command

[Jason Gunthorpe]

On Wed, Oct 30, 2024 at 02:35:34PM -0700, Nicolin Chen wrote:
> Similar to IOMMU_TEST_OP_MD_CHECK_IOTLB verifying a mock_domain's iotlb,
> IOMMU_TEST_OP_DEV_CHECK_CACHE will be used to verify a mock_dev's cache.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/iommufd/iommufd_test.h          |  5 ++++
>  tools/testing/selftests/iommu/iommufd_utils.h | 24 +++++++++++++++++++
>  drivers/iommu/iommufd/selftest.c              | 22 +++++++++++++++++
>  tools/testing/selftests/iommu/iommufd.c       |  7 +++++-
>  4 files changed, 57 insertions(+), 1 deletion(-)

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

Jason

[PATCH v6 09/10] iommufd/selftest: Add vIOMMU coverage for IOMMU_HWPT_INVALIDATE ioctl

[Nicolin Chen]

Add a viommu_cache test function to cover vIOMMU invalidations using the
updated IOMMU_HWPT_INVALIDATE ioctl, which now allows passing in a vIOMMU
via its hwpt_id field.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 tools/testing/selftests/iommu/iommufd_utils.h |  32 ++++
 tools/testing/selftests/iommu/iommufd.c       | 173 ++++++++++++++++++
 2 files changed, 205 insertions(+)

diff --git a/tools/testing/selftests/iommu/iommufd_utils.h b/tools/testing/selftests/iommu/iommufd_utils.h
index 619ffdb1e5e8..c0239f86f2f8 100644
--- a/tools/testing/selftests/iommu/iommufd_utils.h
+++ b/tools/testing/selftests/iommu/iommufd_utils.h
@@ -305,6 +305,38 @@ static int _test_cmd_hwpt_invalidate(int fd, __u32 hwpt_id, void *reqs,
 					     data_type, lreq, nreqs));   \
 	})
 
+static int _test_cmd_viommu_invalidate(int fd, __u32 viommu_id, void *reqs,
+				       uint32_t data_type, uint32_t lreq,
+				       uint32_t *nreqs)
+{
+	struct iommu_hwpt_invalidate cmd = {
+		.size = sizeof(cmd),
+		.hwpt_id = viommu_id,
+		.data_type = data_type,
+		.data_uptr = (uint64_t)reqs,
+		.entry_len = lreq,
+		.entry_num = *nreqs,
+	};
+	int rc = ioctl(fd, IOMMU_HWPT_INVALIDATE, &cmd);
+	*nreqs = cmd.entry_num;
+	return rc;
+}
+
+#define test_cmd_viommu_invalidate(viommu, reqs, lreq, nreqs)                  \
+	({                                                                     \
+		ASSERT_EQ(0,                                                   \
+			  _test_cmd_viommu_invalidate(self->fd, viommu, reqs,  \
+					IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST, \
+					lreq, nreqs));                         \
+	})
+#define test_err_viommu_invalidate(_errno, viommu_id, reqs, data_type, lreq,   \
+				 nreqs)                                        \
+	({                                                                     \
+		EXPECT_ERRNO(_errno, _test_cmd_viommu_invalidate(              \
+					     self->fd, viommu_id, reqs,        \
+					     data_type, lreq, nreqs));         \
+	})
+
 static int _test_cmd_access_replace_ioas(int fd, __u32 access_id,
 					 unsigned int ioas_id)
 {
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index 54f3b81e5479..eeaa403101a4 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -2633,4 +2633,177 @@ TEST_F(iommufd_viommu, vdevice_alloc)
 	}
 }
 
+TEST_F(iommufd_viommu, vdevice_cache)
+{
+	struct iommu_viommu_invalidate_selftest inv_reqs[2] = {};
+	uint32_t viommu_id = self->viommu_id;
+	uint32_t dev_id = self->device_id;
+	uint32_t vdev_id = 0;
+	uint32_t num_inv;
+
+	if (dev_id) {
+		test_cmd_vdevice_alloc(viommu_id, dev_id, 0x99, &vdev_id);
+
+		test_cmd_dev_check_cache_all(dev_id,
+					     IOMMU_TEST_DEV_CACHE_DEFAULT);
+
+		/* Check data_type by passing zero-length array */
+		num_inv = 0;
+		test_cmd_viommu_invalidate(viommu_id, inv_reqs,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: Invalid data_type */
+		num_inv = 1;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST_INVALID,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: structure size sanity */
+		num_inv = 1;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs) + 1, &num_inv);
+		assert(!num_inv);
+
+		num_inv = 1;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   1, &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: invalid flag is passed */
+		num_inv = 1;
+		inv_reqs[0].flags = 0xffffffff;
+		inv_reqs[0].vdev_id = 0x99;
+		test_err_viommu_invalidate(EOPNOTSUPP, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: invalid data_uptr when array is not empty */
+		num_inv = 1;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		test_err_viommu_invalidate(EINVAL, viommu_id, NULL,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: invalid entry_len when array is not empty */
+		num_inv = 1;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   0, &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: invalid cache_id */
+		num_inv = 1;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		inv_reqs[0].cache_id = MOCK_DEV_CACHE_ID_MAX + 1;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(!num_inv);
+
+		/* Negative test: invalid vdev_id */
+		num_inv = 1;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x9;
+		inv_reqs[0].cache_id = 0;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(!num_inv);
+
+		/*
+		 * Invalidate the 1st cache entry but fail the 2nd request
+		 * due to invalid flags configuration in the 2nd request.
+		 */
+		num_inv = 2;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		inv_reqs[0].cache_id = 0;
+		inv_reqs[1].flags = 0xffffffff;
+		inv_reqs[1].vdev_id = 0x99;
+		inv_reqs[1].cache_id = 1;
+		test_err_viommu_invalidate(EOPNOTSUPP, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(num_inv == 1);
+		test_cmd_dev_check_cache(dev_id, 0, 0);
+		test_cmd_dev_check_cache(dev_id, 1,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+		test_cmd_dev_check_cache(dev_id, 2,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+		test_cmd_dev_check_cache(dev_id, 3,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+
+		/*
+		 * Invalidate the 1st cache entry but fail the 2nd request
+		 * due to invalid cache_id configuration in the 2nd request.
+		 */
+		num_inv = 2;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		inv_reqs[0].cache_id = 0;
+		inv_reqs[1].flags = 0;
+		inv_reqs[1].vdev_id = 0x99;
+		inv_reqs[1].cache_id = MOCK_DEV_CACHE_ID_MAX + 1;
+		test_err_viommu_invalidate(EINVAL, viommu_id, inv_reqs,
+					   IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(num_inv == 1);
+		test_cmd_dev_check_cache(dev_id, 0, 0);
+		test_cmd_dev_check_cache(dev_id, 1,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+		test_cmd_dev_check_cache(dev_id, 2,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+		test_cmd_dev_check_cache(dev_id, 3,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+
+		/* Invalidate the 2nd cache entry and verify */
+		num_inv = 1;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		inv_reqs[0].cache_id = 1;
+		test_cmd_viommu_invalidate(viommu_id, inv_reqs,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(num_inv == 1);
+		test_cmd_dev_check_cache(dev_id, 0, 0);
+		test_cmd_dev_check_cache(dev_id, 1, 0);
+		test_cmd_dev_check_cache(dev_id, 2,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+		test_cmd_dev_check_cache(dev_id, 3,
+					 IOMMU_TEST_DEV_CACHE_DEFAULT);
+
+		/* Invalidate the 3rd and 4th cache entries and verify */
+		num_inv = 2;
+		inv_reqs[0].flags = 0;
+		inv_reqs[0].vdev_id = 0x99;
+		inv_reqs[0].cache_id = 2;
+		inv_reqs[1].flags = 0;
+		inv_reqs[1].vdev_id = 0x99;
+		inv_reqs[1].cache_id = 3;
+		test_cmd_viommu_invalidate(viommu_id, inv_reqs,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(num_inv == 2);
+		test_cmd_dev_check_cache_all(dev_id, 0);
+
+		/* Invalidate all cache entries for nested_dev_id[1] and verify */
+		num_inv = 1;
+		inv_reqs[0].vdev_id = 0x99;
+		inv_reqs[0].flags = IOMMU_TEST_INVALIDATE_FLAG_ALL;
+		test_cmd_viommu_invalidate(viommu_id, inv_reqs,
+					   sizeof(*inv_reqs), &num_inv);
+		assert(num_inv == 1);
+		test_cmd_dev_check_cache_all(dev_id, 0);
+		test_ioctl_destroy(vdev_id);
+	}
+}
+
 TEST_HARNESS_MAIN
-- 
2.43.0

Re: [PATCH v6 09/10] iommufd/selftest: Add vIOMMU coverage for IOMMU_HWPT_INVALIDATE ioctl

[Jason Gunthorpe]

On Wed, Oct 30, 2024 at 02:35:35PM -0700, Nicolin Chen wrote:
> Add a viommu_cache test function to cover vIOMMU invalidations using the
> updated IOMMU_HWPT_INVALIDATE ioctl, which now allows passing in a vIOMMU
> via its hwpt_id field.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  tools/testing/selftests/iommu/iommufd_utils.h |  32 ++++
>  tools/testing/selftests/iommu/iommufd.c       | 173 ++++++++++++++++++
>  2 files changed, 205 insertions(+)

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

Jason

[PATCH v6 10/10] Documentation: userspace-api: iommufd: Update vDEVICE

[Nicolin Chen]

With the introduction of the new object and its infrastructure, update the
doc and the vIOMMU graph to reflect that.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 Documentation/userspace-api/iommufd.rst | 41 +++++++++++++++++++------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/Documentation/userspace-api/iommufd.rst b/Documentation/userspace-api/iommufd.rst
index a8b7766c2849..0ef22b3ca30b 100644
--- a/Documentation/userspace-api/iommufd.rst
+++ b/Documentation/userspace-api/iommufd.rst
@@ -94,6 +94,19 @@ Following IOMMUFD objects are exposed to userspace:
      backed by corresponding vIOMMU objects, in which case a guest OS would do
      the "dispatch" naturally instead of VMM trappings.
 
+- IOMMUFD_OBJ_VDEVICE, representing a virtual device for an IOMMUFD_OBJ_DEVICE
+  against an IOMMUFD_OBJ_VIOMMU. This virtual device holds the device's virtual
+  information or attributes (related to the vIOMMU) in a VM. An immediate vDATA
+  example can be the virtual ID of the device on a vIOMMU, which is a unique ID
+  that VMM assigns to the device for a translation channel/port of the vIOMMU,
+  e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to a
+  Context Table. Potential use cases of some advanced security information can
+  be forwarded via this object too, such as security level or realm information
+  in a Confidential Compute Architecture. A VMM should create a vDEVICE object
+  to forward all the device information in a VM, when it connects a device to a
+  vIOMMU, which is a separate ioctl call from attaching the same device to an
+  HWPT_PAGING that the vIOMMU holds.
+
 All user-visible objects are destroyed via the IOMMU_DESTROY uAPI.
 
 The diagrams below show relationships between user-visible objects and kernel
@@ -133,16 +146,16 @@ creating the objects and links::
                          |____________|     |____________|     |______|
 
   _______________________________________________________________________
- |                      iommufd (with vIOMMU)                            |
+ |                      iommufd (with vIOMMU/vDEVICE)                    |
  |                                                                       |
- |                             [5]                                       |
- |                        _____________                                  |
- |                       |             |                                 |
- |      |----------------|    vIOMMU   |                                 |
- |      |                |             |                                 |
- |      |                |             |                                 |
- |      |      [1]       |             |          [4]             [2]    |
- |      |     ______     |             |     _____________     ________  |
+ |                             [5]                [6]                    |
+ |                        _____________      _____________               |
+ |                       |             |    |             |              |
+ |      |----------------|    vIOMMU   |<---|   vDEVICE   |<----|        |
+ |      |                |             |    |_____________|     |        |
+ |      |                |             |                        |        |
+ |      |      [1]       |             |          [4]           | [2]    |
+ |      |     ______     |             |     _____________     _|______  |
  |      |    |      |    |     [3]     |    |             |   |        | |
  |      |    | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
  |      |    |______|    |_____________|    |_____________|   |________| |
@@ -215,6 +228,15 @@ creating the objects and links::
    the vIOMMU object and the HWPT_PAGING, then this vIOMMU object can be used
    as a nesting parent object to allocate an HWPT_NESTED object described above.
 
+6. IOMMUFD_OBJ_VDEVICE can be only manually created via the IOMMU_VDEVICE_ALLOC
+   uAPI, provided a viommu_id for an iommufd_viommu object and a dev_id for an
+   iommufd_device object. The vDEVICE object will be the binding between these
+   two parent objects. Another @virt_id will be also set via the uAPI providing
+   the iommufd core an index to store the vDEVICE object to a vDEVICE array per
+   vIOMMU. If necessary, the IOMMU driver may choose to implement a vdevce_alloc
+   op to init its HW for virtualization feature related to a vDEVICE. Successful
+   completion of this operation sets up the linkages between vIOMMU and device.
+
 A device can only bind to an iommufd due to DMA ownership claim and attach to at
 most one IOAS object (no support of PASID yet).
 
@@ -228,6 +250,7 @@ User visible objects are backed by following datastructures:
 - iommufd_hwpt_paging for IOMMUFD_OBJ_HWPT_PAGING.
 - iommufd_hwpt_nested for IOMMUFD_OBJ_HWPT_NESTED.
 - iommufd_viommu for IOMMUFD_OBJ_VIOMMU.
+- iommufd_vdevice for IOMMUFD_OBJ_VDEVICE
 
 Several terminologies when looking at these datastructures:
 
-- 
2.43.0

Re: [PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Zhangfei Gao]

On Thu, 31 Oct 2024 at 05:36, Nicolin Chen <nicolinc@nvidia.com> wrote:
>
> Following the previous vIOMMU series, this adds another vDEVICE structure,
> representing the association from an iommufd_device to an iommufd_viommu.
> This gives the whole architecture a new "v" layer:
>   _______________________________________________________________________
>  |                      iommufd (with vIOMMU/vDEVICE)                    |
>  |                        _____________      _____________               |
>  |                       |             |    |             |              |
>  |      |----------------|    vIOMMU   |<---|   vDEVICE   |<------|      |
>  |      |                |             |    |_____________|       |      |
>  |      |     ______     |             |     _____________     ___|____  |
>  |      |    |      |    |             |    |             |   |        | |
>  |      |    | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
>  |      |    |______|    |_____________|    |_____________|   |________| |
>  |______|________|______________|__________________|_______________|_____|
>         |        |              |                  |               |
>   ______v_____   |        ______v_____       ______v_____       ___v__
>  |   struct   |  |  PFN  |  (paging)  |     |  (nested)  |     |struct|
>  |iommu_device|  |------>|iommu_domain|<----|iommu_domain|<----|device|
>  |____________|   storage|____________|     |____________|     |______|
>
> This vDEVICE object is used to collect and store all vIOMMU-related device
> information/attributes in a VM. As an initial series for vDEVICE, add only
> the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM:
> e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to
> a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID
> of the device against the physical IOMMU instance. This is essential for a
> vIOMMU-based invalidation, where the request contains a device's vID for a
> device cache flush, e.g. ATC invalidation.
>
> Therefore, with this vDEVICE object, support a vIOMMU-based invalidation,
> by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache
> with a given driver data.
>
> As for the implementation of the series, add driver support in ARM SMMUv3
> for a real world use case.
>
> This series is on Github:
> https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v6
> (QEMU branch for testing will be provided in Jason's nesting series)

Thanks Nico

I tested on aarch64, functions are OK.

But with some hacks
https://github.com/Linaro/linux-kernel-uadk/commit/22f47d6f3a34a0867a187473bd5ba0e0ee3395d4

Thanks

Re: [PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Jason Gunthorpe]

On Thu, Oct 31, 2024 at 02:28:12PM +0800, Zhangfei Gao wrote:

> > As for the implementation of the series, add driver support in ARM SMMUv3
> > for a real world use case.
> >
> > This series is on Github:
> > https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v6
> > (QEMU branch for testing will be provided in Jason's nesting series)
> 
> Thanks Nico
> 
> I tested on aarch64, functions are OK.
> 
> But with some hacks
> https://github.com/Linaro/linux-kernel-uadk/commit/22f47d6f3a34a0867a187473bd5ba0e0ee3395d4

Hmm, it seems like we should permit IOMMU_HWPT_FAULT_ID_VALID domain
creation on ARM?

Jason

Re: [PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Nicolin Chen]

On Thu, Oct 31, 2024 at 08:59:37AM -0300, Jason Gunthorpe wrote:
> On Thu, Oct 31, 2024 at 02:28:12PM +0800, Zhangfei Gao wrote:
> 
> > > As for the implementation of the series, add driver support in ARM SMMUv3
> > > for a real world use case.
> > >
> > > This series is on Github:
> > > https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v6
> > > (QEMU branch for testing will be provided in Jason's nesting series)
> > 
> > Thanks Nico
> > 
> > I tested on aarch64, functions are OK.
> > 
> > But with some hacks
> > https://github.com/Linaro/linux-kernel-uadk/commit/22f47d6f3a34a0867a187473bd5ba0e0ee3395d4
> 
> Hmm, it seems like we should permit IOMMU_HWPT_FAULT_ID_VALID domain
> creation on ARM?

+1, since we proved PRI could work :)

Thanks
Nicolin

Re: [PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Nicolin Chen]

On Thu, Oct 31, 2024 at 02:28:12PM +0800, Zhangfei Gao wrote:
> On Thu, 31 Oct 2024 at 05:36, Nicolin Chen <nicolinc@nvidia.com> wrote:
> >
> > Following the previous vIOMMU series, this adds another vDEVICE structure,
> > representing the association from an iommufd_device to an iommufd_viommu.
> > This gives the whole architecture a new "v" layer:
> >   _______________________________________________________________________
> >  |                      iommufd (with vIOMMU/vDEVICE)                    |
> >  |                        _____________      _____________               |
> >  |                       |             |    |             |              |
> >  |      |----------------|    vIOMMU   |<---|   vDEVICE   |<------|      |
> >  |      |                |             |    |_____________|       |      |
> >  |      |     ______     |             |     _____________     ___|____  |
> >  |      |    |      |    |             |    |             |   |        | |
> >  |      |    | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
> >  |      |    |______|    |_____________|    |_____________|   |________| |
> >  |______|________|______________|__________________|_______________|_____|
> >         |        |              |                  |               |
> >   ______v_____   |        ______v_____       ______v_____       ___v__
> >  |   struct   |  |  PFN  |  (paging)  |     |  (nested)  |     |struct|
> >  |iommu_device|  |------>|iommu_domain|<----|iommu_domain|<----|device|
> >  |____________|   storage|____________|     |____________|     |______|
> >
> > This vDEVICE object is used to collect and store all vIOMMU-related device
> > information/attributes in a VM. As an initial series for vDEVICE, add only
> > the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM:
> > e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to
> > a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID
> > of the device against the physical IOMMU instance. This is essential for a
> > vIOMMU-based invalidation, where the request contains a device's vID for a
> > device cache flush, e.g. ATC invalidation.
> >
> > Therefore, with this vDEVICE object, support a vIOMMU-based invalidation,
> > by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache
> > with a given driver data.
> >
> > As for the implementation of the series, add driver support in ARM SMMUv3
> > for a real world use case.
> >
> > This series is on Github:
> > https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v6
> > (QEMU branch for testing will be provided in Jason's nesting series)
> 
> Thanks Nico
> 
> I tested on aarch64, functions are OK.
> 
> But with some hacks
> https://github.com/Linaro/linux-kernel-uadk/commit/22f47d6f3a34a0867a187473bd5ba0e0ee3395d4

Though we will have some small changes to this two series (and
possibly a small change to SMMUv3 driver too for that flags in
the hacks), would you mind giving this two series a Tested-by?

Thanks!
Nicolin