[PATCH vhost v4 00/16] vdpa: Add support for vq descriptor mappings

[PATCH vhost v4 00/16] vdpa: Add support for vq descriptor mappings

[Dragos Tatulea]

This patch series adds support for vq descriptor table mappings which
are used to improve vdpa live migration downtime. The improvement comes
from using smaller mappings which take less time to create and destroy
in hw.

The first part adds the vdpa core changes from Si-Wei [0].

The second part adds support in mlx5_vdpa:
- Refactor the mr code to be able to cleanly add descriptor mappings.
- Add hardware descriptor mr support.
- Properly update iotlb for cvq during ASID switch.

Changes in v4:

- Improved the handling of empty iotlbs. See mlx5_vdpa_change_map
  section in patch "12/16 vdpa/mlx5: Improve mr upate flow".
- Fixed a invalid usage of desc_group_mkey hw vq field when the
  capability is not there. See patch
  "15/16 vdpa/mlx5: Enable hw support for vq descriptor map".

Changes in v3:

- dup_iotlb now checks for src == dst case and returns an error.
- Renamed iotlb parameter in dup_iotlb to dst.
- Removed a redundant check of the asid value.
- Fixed a commit message.
- mx5_ifc.h patch has been applied to mlx5-vhost tree. When applying
  this series please pull from that tree first.

Changes in v2:

- The "vdpa/mlx5: Enable hw support for vq descriptor mapping" change
  was split off into two patches to avoid merge conflicts into the tree
  of Linus.

  The first patch contains only changes for mlx5_ifc.h. This must be
  applied into the mlx5-vdpa tree [1] first. Once this patch is applied
  on mlx5-vdpa, the change has to be pulled fom mlx5-vdpa into the vhost
  tree and only then the remaining patches can be applied.

[0] https://lore.kernel.org/virtualization/1694248959-13369-1-git-send-email-si-wei.liu@oracle.com
[1] https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-vhost

Dragos Tatulea (13):
  vdpa/mlx5: Expose descriptor group mkey hw capability
  vdpa/mlx5: Create helper function for dma mappings
  vdpa/mlx5: Decouple cvq iotlb handling from hw mapping code
  vdpa/mlx5: Take cvq iotlb lock during refresh
  vdpa/mlx5: Collapse "dvq" mr add/delete functions
  vdpa/mlx5: Rename mr destroy functions
  vdpa/mlx5: Allow creation/deletion of any given mr struct
  vdpa/mlx5: Move mr mutex out of mr struct
  vdpa/mlx5: Improve mr update flow
  vdpa/mlx5: Introduce mr for vq descriptor
  vdpa/mlx5: Enable hw support for vq descriptor mapping
  vdpa/mlx5: Make iotlb helper functions more generic
  vdpa/mlx5: Update cvq iotlb mapping on ASID change

Si-Wei Liu (3):
  vdpa: introduce dedicated descriptor group for virtqueue
  vhost-vdpa: introduce descriptor group backend feature
  vhost-vdpa: uAPI to get dedicated descriptor group id

 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  31 +++--
 drivers/vdpa/mlx5/core/mr.c        | 194 ++++++++++++++++-------------
 drivers/vdpa/mlx5/core/resources.c |   6 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 105 +++++++++++-----
 drivers/vhost/vdpa.c               |  27 ++++
 include/linux/mlx5/mlx5_ifc.h      |   8 +-
 include/linux/mlx5/mlx5_ifc_vdpa.h |   7 +-
 include/linux/vdpa.h               |  11 ++
 include/uapi/linux/vhost.h         |   8 ++
 include/uapi/linux/vhost_types.h   |   5 +
 10 files changed, 272 insertions(+), 130 deletions(-)

-- 
2.41.0

[PATCH vhost v4 01/16] vdpa/mlx5: Expose descriptor group mkey hw capability

[Dragos Tatulea]

Necessary for improved live migration flow. Actual support will be added
in a downstream patch.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
---
 include/linux/mlx5/mlx5_ifc.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/mlx5/mlx5_ifc.h b/include/linux/mlx5/mlx5_ifc.h
index b23d8ff286a1..6b6be1a0d575 100644
--- a/include/linux/mlx5/mlx5_ifc.h
+++ b/include/linux/mlx5/mlx5_ifc.h
@@ -1231,7 +1231,13 @@ struct mlx5_ifc_virtio_emulation_cap_bits {
 	u8         max_emulated_devices[0x8];
 	u8         max_num_virtio_queues[0x18];
 
-	u8         reserved_at_a0[0x60];
+	u8         reserved_at_a0[0x20];
+
+	u8	   reserved_at_c0[0x13];
+	u8         desc_group_mkey_supported[0x1];
+	u8         reserved_at_d4[0xc];
+
+	u8         reserved_at_e0[0x20];
 
 	u8         umem_1_buffer_param_a[0x20];
 
-- 
2.41.0

[PATCH vhost v4 02/16] vdpa: introduce dedicated descriptor group for virtqueue

[Dragos Tatulea]

From: Si-Wei Liu <si-wei.liu@oracle.com>

In some cases, the access to the virtqueue's descriptor area, device
and driver areas (precluding indirect descriptor table in guest memory)
may have to be confined to a different address space than where its
buffers reside. Without loss of simplicity and generality with already
established terminology, let's fold up these 3 areas and call them
as a whole as descriptor table group, or descriptor group for short.
Specifically, in case of split virtqueues, descriptor group consists of
regions for Descriptor Table, Available Ring and Used Ring; for packed
virtqueues layout, descriptor group contains Descriptor Ring, Driver
and Device Event Suppression structures.

The group ID for a dedicated descriptor group can be obtained through a
new .get_vq_desc_group() op. If driver implements this op, it means that
the descriptor, device and driver areas of the virtqueue may reside
in a dedicated group than where its buffers reside, a.k.a the default
virtqueue group through the .get_vq_group() op.

In principle, the descriptor group may or may not have same group ID
as the default group. Even if the descriptor group has a different ID,
meaning the vq's descriptor group areas can optionally move to a
separate address space than where guest memory resides, the descriptor
group may still start from a default address space, same as where its
buffers reside. To move the descriptor group to a different address
space, .set_group_asid() has to be called to change the ASID binding
for the group, which is no different than what needs to be done on any
other virtqueue group. On the other hand, the .reset() semantics also
applies on descriptor table group, meaning the device reset will clear
all ASID bindings and move all virtqueue groups including descriptor
group back to the default address space, i.e. in ASID 0.

QEMU's shadow virtqueue is going to utilize dedicated descriptor group
to speed up map and unmap operations, yielding tremendous downtime
reduction by avoiding the full and slow remap cycle in SVQ switching.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 include/linux/vdpa.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 0e652026b776..d376309b99cf 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -204,6 +204,16 @@ struct vdpa_map_file {
  *				@vdev: vdpa device
  *				@idx: virtqueue index
  *				Returns u32: group id for this virtqueue
+ * @get_vq_desc_group:		Get the group id for the descriptor table of
+ *				a specific virtqueue (optional)
+ *				@vdev: vdpa device
+ *				@idx: virtqueue index
+ *				Returns u32: group id for the descriptor table
+ *				portion of this virtqueue. Could be different
+ *				than the one from @get_vq_group, in which case
+ *				the access to the descriptor table can be
+ *				confined to a separate asid, isolating from
+ *				the virtqueue's buffer address access.
  * @get_device_features:	Get virtio features supported by the device
  *				@vdev: vdpa device
  *				Returns the virtio features support by the
@@ -360,6 +370,7 @@ struct vdpa_config_ops {
 	/* Device ops */
 	u32 (*get_vq_align)(struct vdpa_device *vdev);
 	u32 (*get_vq_group)(struct vdpa_device *vdev, u16 idx);
+	u32 (*get_vq_desc_group)(struct vdpa_device *vdev, u16 idx);
 	u64 (*get_device_features)(struct vdpa_device *vdev);
 	u64 (*get_backend_features)(const struct vdpa_device *vdev);
 	int (*set_driver_features)(struct vdpa_device *vdev, u64 features);
-- 
2.41.0

[PATCH vhost v4 03/16] vhost-vdpa: introduce descriptor group backend feature

[Dragos Tatulea]

From: Si-Wei Liu <si-wei.liu@oracle.com>

Userspace knows if the device has dedicated descriptor group or not
by checking this feature bit.

It's only exposed if the vdpa driver backend implements the
.get_vq_desc_group() operation callback. Userspace trying to negotiate
this feature when it or the dependent _F_IOTLB_ASID feature hasn't
been exposed will result in an error.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vdpa.c             | 17 +++++++++++++++++
 include/uapi/linux/vhost_types.h |  5 +++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 78379ffd2336..2f21798a37ee 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -389,6 +389,14 @@ static bool vhost_vdpa_can_resume(const struct vhost_vdpa *v)
 	return ops->resume;
 }
 
+static bool vhost_vdpa_has_desc_group(const struct vhost_vdpa *v)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+
+	return ops->get_vq_desc_group;
+}
+
 static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
 {
 	struct vdpa_device *vdpa = v->vdpa;
@@ -690,6 +698,7 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 		if (copy_from_user(&features, featurep, sizeof(features)))
 			return -EFAULT;
 		if (features & ~(VHOST_VDPA_BACKEND_FEATURES |
+				 BIT_ULL(VHOST_BACKEND_F_DESC_ASID) |
 				 BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
 				 BIT_ULL(VHOST_BACKEND_F_RESUME) |
 				 BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
@@ -700,6 +709,12 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 		if ((features & BIT_ULL(VHOST_BACKEND_F_RESUME)) &&
 		     !vhost_vdpa_can_resume(v))
 			return -EOPNOTSUPP;
+		if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
+		    !(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
+			return -EINVAL;
+		if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
+		     !vhost_vdpa_has_desc_group(v))
+			return -EOPNOTSUPP;
 		vhost_set_backend_features(&v->vdev, features);
 		return 0;
 	}
@@ -753,6 +768,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 			features |= BIT_ULL(VHOST_BACKEND_F_SUSPEND);
 		if (vhost_vdpa_can_resume(v))
 			features |= BIT_ULL(VHOST_BACKEND_F_RESUME);
+		if (vhost_vdpa_has_desc_group(v))
+			features |= BIT_ULL(VHOST_BACKEND_F_DESC_ASID);
 		features |= vhost_vdpa_get_backend_features(v);
 		if (copy_to_user(featurep, &features, sizeof(features)))
 			r = -EFAULT;
diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
index 2d827d22cd99..18ad6ae7ab5c 100644
--- a/include/uapi/linux/vhost_types.h
+++ b/include/uapi/linux/vhost_types.h
@@ -185,5 +185,10 @@ struct vhost_vdpa_iova_range {
  * DRIVER_OK
  */
 #define VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK  0x6
+/* Device may expose the virtqueue's descriptor area, driver area and
+ * device area to a different group for ASID binding than where its
+ * buffers may reside. Requires VHOST_BACKEND_F_IOTLB_ASID.
+ */
+#define VHOST_BACKEND_F_DESC_ASID    0x7
 
 #endif
-- 
2.41.0

[PATCH vhost v4 04/16] vhost-vdpa: uAPI to get dedicated descriptor group id

[Dragos Tatulea]

From: Si-Wei Liu <si-wei.liu@oracle.com>

With _F_DESC_ASID backend feature, the device can now support the
VHOST_VDPA_GET_VRING_DESC_GROUP ioctl, and it may expose the descriptor
table (including avail and used ring) in a different group than the
buffers it contains. This new uAPI will fetch the group ID of the
descriptor table.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vdpa.c       | 10 ++++++++++
 include/uapi/linux/vhost.h |  8 ++++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 2f21798a37ee..851535f57b95 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -613,6 +613,16 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 		else if (copy_to_user(argp, &s, sizeof(s)))
 			return -EFAULT;
 		return 0;
+	case VHOST_VDPA_GET_VRING_DESC_GROUP:
+		if (!vhost_vdpa_has_desc_group(v))
+			return -EOPNOTSUPP;
+		s.index = idx;
+		s.num = ops->get_vq_desc_group(vdpa, idx);
+		if (s.num >= vdpa->ngroups)
+			return -EIO;
+		else if (copy_to_user(argp, &s, sizeof(s)))
+			return -EFAULT;
+		return 0;
 	case VHOST_VDPA_SET_GROUP_ASID:
 		if (copy_from_user(&s, argp, sizeof(s)))
 			return -EFAULT;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index f5c48b61ab62..649560c685f1 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -219,4 +219,12 @@
  */
 #define VHOST_VDPA_RESUME		_IO(VHOST_VIRTIO, 0x7E)
 
+/* Get the group for the descriptor table including driver & device areas
+ * of a virtqueue: read index, write group in num.
+ * The virtqueue index is stored in the index field of vhost_vring_state.
+ * The group ID of the descriptor table for this specific virtqueue
+ * is returned via num field of vhost_vring_state.
+ */
+#define VHOST_VDPA_GET_VRING_DESC_GROUP	_IOWR(VHOST_VIRTIO, 0x7F,	\
+					      struct vhost_vring_state)
 #endif
-- 
2.41.0

[PATCH vhost v4 05/16] vdpa/mlx5: Create helper function for dma mappings

[Dragos Tatulea]

Necessary for upcoming cvq separation from mr allocation.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h | 1 +
 drivers/vdpa/mlx5/core/mr.c        | 5 +++++
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 4 ++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index ca56242972b3..3748f027cfe9 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -120,6 +120,7 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			unsigned int asid);
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev);
 void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
+int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev);
 
 #define mlx5_vdpa_warn(__dev, format, ...)                                                         \
 	dev_warn((__dev)->mdev->device, "%s:%d:(pid %d) warning: " format, __func__, __LINE__,     \
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 5a1971fcd87b..7bd0883b8b25 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -619,3 +619,8 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io
 
 	return err;
 }
+
+int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
+{
+	return mlx5_vdpa_create_mr(mvdev, NULL, 0);
+}
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 40a03b08d7cf..65b6a54ad344 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2836,7 +2836,7 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
 	++mvdev->generation;
 
 	if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
-		if (mlx5_vdpa_create_mr(mvdev, NULL, 0))
+		if (mlx5_vdpa_create_dma_mr(mvdev))
 			mlx5_vdpa_warn(mvdev, "create MR failed\n");
 	}
 	up_write(&ndev->reslock);
@@ -3441,7 +3441,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 		goto err_mpfs;
 
 	if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
-		err = mlx5_vdpa_create_mr(mvdev, NULL, 0);
+		err = mlx5_vdpa_create_dma_mr(mvdev);
 		if (err)
 			goto err_res;
 	}
-- 
2.41.0

[PATCH vhost v4 06/16] vdpa/mlx5: Decouple cvq iotlb handling from hw mapping code

[Dragos Tatulea]

The handling of the cvq iotlb is currently coupled with the creation
and destruction of the hardware mkeys (mr).

This patch moves cvq iotlb handling into its own function and shifts it
to a scope that is not related to mr handling. As cvq handling is just a
prune_iotlb + dup_iotlb cycle, put it all in the same "update" function.
Finally, the destruction path is handled by directly pruning the iotlb.

After this move is done the ASID mr code can be collapsed into a single
function.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  3 ++
 drivers/vdpa/mlx5/core/mr.c        | 57 +++++++++++-------------------
 drivers/vdpa/mlx5/net/mlx5_vnet.c  |  7 ++--
 3 files changed, 28 insertions(+), 39 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index 3748f027cfe9..554899a80241 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -120,6 +120,9 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			unsigned int asid);
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev);
 void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
+int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
+				struct vhost_iotlb *iotlb,
+				unsigned int asid);
 int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev);
 
 #define mlx5_vdpa_warn(__dev, format, ...)                                                         \
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 7bd0883b8b25..fcb6ae32e9ed 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -489,14 +489,6 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr
 	}
 }
 
-static void _mlx5_vdpa_destroy_cvq_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
-{
-	if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
-		return;
-
-	prune_iotlb(mvdev);
-}
-
 static void _mlx5_vdpa_destroy_dvq_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
 {
 	struct mlx5_vdpa_mr *mr = &mvdev->mr;
@@ -522,25 +514,14 @@ void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
 	mutex_lock(&mr->mkey_mtx);
 
 	_mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
-	_mlx5_vdpa_destroy_cvq_mr(mvdev, asid);
 
 	mutex_unlock(&mr->mkey_mtx);
 }
 
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
 {
-	mlx5_vdpa_destroy_mr_asid(mvdev, mvdev->group2asid[MLX5_VDPA_CVQ_GROUP]);
 	mlx5_vdpa_destroy_mr_asid(mvdev, mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]);
-}
-
-static int _mlx5_vdpa_create_cvq_mr(struct mlx5_vdpa_dev *mvdev,
-				    struct vhost_iotlb *iotlb,
-				    unsigned int asid)
-{
-	if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
-		return 0;
-
-	return dup_iotlb(mvdev, iotlb);
+	prune_iotlb(mvdev);
 }
 
 static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
@@ -572,22 +553,7 @@ static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
 static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
 				struct vhost_iotlb *iotlb, unsigned int asid)
 {
-	int err;
-
-	err = _mlx5_vdpa_create_dvq_mr(mvdev, iotlb, asid);
-	if (err)
-		return err;
-
-	err = _mlx5_vdpa_create_cvq_mr(mvdev, iotlb, asid);
-	if (err)
-		goto out_err;
-
-	return 0;
-
-out_err:
-	_mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
-
-	return err;
+	return _mlx5_vdpa_create_dvq_mr(mvdev, iotlb, asid);
 }
 
 int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
@@ -620,7 +586,24 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io
 	return err;
 }
 
+int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
+				struct vhost_iotlb *iotlb,
+				unsigned int asid)
+{
+	if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
+		return 0;
+
+	prune_iotlb(mvdev);
+	return dup_iotlb(mvdev, iotlb);
+}
+
 int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
 {
-	return mlx5_vdpa_create_mr(mvdev, NULL, 0);
+	int err;
+
+	err = mlx5_vdpa_create_mr(mvdev, NULL, 0);
+	if (err)
+		return err;
+
+	return mlx5_vdpa_update_cvq_iotlb(mvdev, NULL, 0);
 }
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 65b6a54ad344..aa4896662699 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2884,10 +2884,13 @@ static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 		return err;
 	}
 
-	if (change_map)
+	if (change_map) {
 		err = mlx5_vdpa_change_map(mvdev, iotlb, asid);
+		if (err)
+			return err;
+	}
 
-	return err;
+	return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
 }
 
 static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
-- 
2.41.0

[PATCH vhost v4 07/16] vdpa/mlx5: Take cvq iotlb lock during refresh

[Dragos Tatulea]

The reslock is taken while refresh is called but iommu_lock is more
specific to this resource. So take the iommu_lock during cvq iotlb
refresh.

Based on Eugenio's patch [0].

[0] https://lore.kernel.org/lkml/20230112142218.725622-4-eperezma@redhat.com/

Acked-by: Jason Wang <jasowang@redhat.com>
Suggested-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mr.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index fcb6ae32e9ed..587300e7c18e 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -590,11 +590,19 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 				struct vhost_iotlb *iotlb,
 				unsigned int asid)
 {
+	int err;
+
 	if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
 		return 0;
 
+	spin_lock(&mvdev->cvq.iommu_lock);
+
 	prune_iotlb(mvdev);
-	return dup_iotlb(mvdev, iotlb);
+	err = dup_iotlb(mvdev, iotlb);
+
+	spin_unlock(&mvdev->cvq.iommu_lock);
+
+	return err;
 }
 
 int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
-- 
2.41.0

[PATCH vhost v4 08/16] vdpa/mlx5: Collapse "dvq" mr add/delete functions

[Dragos Tatulea]

Now that the cvq code is out of mlx5_vdpa_create/destroy_mr, the "dvq"
functions can be folded into their callers.

Having "dvq" in the naming will no longer be accurate in the downstream
patches.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mr.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 587300e7c18e..fde00497f4ad 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -489,7 +489,7 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr
 	}
 }
 
-static void _mlx5_vdpa_destroy_dvq_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
+static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
 {
 	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 
@@ -513,7 +513,7 @@ void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
 
 	mutex_lock(&mr->mkey_mtx);
 
-	_mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
+	_mlx5_vdpa_destroy_mr(mvdev, asid);
 
 	mutex_unlock(&mr->mkey_mtx);
 }
@@ -524,9 +524,9 @@ void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
 	prune_iotlb(mvdev);
 }
 
-static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
-				    struct vhost_iotlb *iotlb,
-				    unsigned int asid)
+static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
+				struct vhost_iotlb *iotlb,
+				unsigned int asid)
 {
 	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 	int err;
@@ -550,12 +550,6 @@ static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
 	return 0;
 }
 
-static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
-				struct vhost_iotlb *iotlb, unsigned int asid)
-{
-	return _mlx5_vdpa_create_dvq_mr(mvdev, iotlb, asid);
-}
-
 int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			unsigned int asid)
 {
-- 
2.41.0

[PATCH vhost v4 09/16] vdpa/mlx5: Rename mr destroy functions

[Dragos Tatulea]

Make mlx5_destroy_mr symmetric to mlx5_create_mr.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  4 ++--
 drivers/vdpa/mlx5/core/mr.c        |  6 +++---
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 12 ++++++------
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index 554899a80241..e1e6e7aba50e 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -118,8 +118,8 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io
 			     bool *change_map, unsigned int asid);
 int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			unsigned int asid);
-void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev);
-void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
+void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
+void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
 int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 				struct vhost_iotlb *iotlb,
 				unsigned int asid);
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index fde00497f4ad..00dcce190a1f 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -507,7 +507,7 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid
 	mr->initialized = false;
 }
 
-void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
+void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
 {
 	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 
@@ -518,9 +518,9 @@ void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
 	mutex_unlock(&mr->mkey_mtx);
 }
 
-void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
+void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
 {
-	mlx5_vdpa_destroy_mr_asid(mvdev, mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]);
+	mlx5_vdpa_destroy_mr(mvdev, mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]);
 	prune_iotlb(mvdev);
 }
 
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index aa4896662699..ab196c43694c 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2644,7 +2644,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 		goto err_mr;
 
 	teardown_driver(ndev);
-	mlx5_vdpa_destroy_mr_asid(mvdev, asid);
+	mlx5_vdpa_destroy_mr(mvdev, asid);
 	err = mlx5_vdpa_create_mr(mvdev, iotlb, asid);
 	if (err)
 		goto err_mr;
@@ -2660,7 +2660,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 	return 0;
 
 err_setup:
-	mlx5_vdpa_destroy_mr_asid(mvdev, asid);
+	mlx5_vdpa_destroy_mr(mvdev, asid);
 err_mr:
 	return err;
 }
@@ -2797,7 +2797,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
 err_driver:
 	unregister_link_notifier(ndev);
 err_setup:
-	mlx5_vdpa_destroy_mr(&ndev->mvdev);
+	mlx5_vdpa_destroy_mr_resources(&ndev->mvdev);
 	ndev->mvdev.status |= VIRTIO_CONFIG_S_FAILED;
 err_clear:
 	up_write(&ndev->reslock);
@@ -2824,7 +2824,7 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
 	unregister_link_notifier(ndev);
 	teardown_driver(ndev);
 	clear_vqs_ready(ndev);
-	mlx5_vdpa_destroy_mr(&ndev->mvdev);
+	mlx5_vdpa_destroy_mr_resources(&ndev->mvdev);
 	ndev->mvdev.status = 0;
 	ndev->mvdev.suspended = false;
 	ndev->cur_num_vqs = 0;
@@ -2944,7 +2944,7 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev)
 	ndev = to_mlx5_vdpa_ndev(mvdev);
 
 	free_resources(ndev);
-	mlx5_vdpa_destroy_mr(mvdev);
+	mlx5_vdpa_destroy_mr_resources(mvdev);
 	if (!is_zero_ether_addr(ndev->config.mac)) {
 		pfmdev = pci_get_drvdata(pci_physfn(mvdev->mdev->pdev));
 		mlx5_mpfs_del_mac(pfmdev, ndev->config.mac);
@@ -3474,7 +3474,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 err_res2:
 	free_resources(ndev);
 err_mr:
-	mlx5_vdpa_destroy_mr(mvdev);
+	mlx5_vdpa_destroy_mr_resources(mvdev);
 err_res:
 	mlx5_vdpa_free_resources(&ndev->mvdev);
 err_mpfs:
-- 
2.41.0

[PATCH vhost v4 10/16] vdpa/mlx5: Allow creation/deletion of any given mr struct

[Dragos Tatulea]

This patch adapts the mr creation/deletion code to be able to work with
any given mr struct pointer. All the APIs are adapted to take an extra
parameter for the mr.

mlx5_vdpa_create/delete_mr doesn't need a ASID parameter anymore. The
check is done in the caller instead (mlx5_set_map).

This change is needed for a followup patch which will introduce an
additional mr for the vq descriptor data.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  8 +++--
 drivers/vdpa/mlx5/core/mr.c        | 53 ++++++++++++++----------------
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 10 ++++--
 3 files changed, 36 insertions(+), 35 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index e1e6e7aba50e..01d4ee58ccb1 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -116,10 +116,12 @@ int mlx5_vdpa_create_mkey(struct mlx5_vdpa_dev *mvdev, u32 *mkey, u32 *in,
 int mlx5_vdpa_destroy_mkey(struct mlx5_vdpa_dev *mvdev, u32 mkey);
 int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			     bool *change_map, unsigned int asid);
-int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
-			unsigned int asid);
+int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
+			struct mlx5_vdpa_mr *mr,
+			struct vhost_iotlb *iotlb);
 void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
-void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
+void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
+			  struct mlx5_vdpa_mr *mr);
 int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 				struct vhost_iotlb *iotlb,
 				unsigned int asid);
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 00dcce190a1f..6f29e8eaabb1 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -301,10 +301,13 @@ static void unmap_direct_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_direct
 	sg_free_table(&mr->sg_head);
 }
 
-static int add_direct_chain(struct mlx5_vdpa_dev *mvdev, u64 start, u64 size, u8 perm,
+static int add_direct_chain(struct mlx5_vdpa_dev *mvdev,
+			    struct mlx5_vdpa_mr *mr,
+			    u64 start,
+			    u64 size,
+			    u8 perm,
 			    struct vhost_iotlb *iotlb)
 {
-	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 	struct mlx5_vdpa_direct_mr *dmr;
 	struct mlx5_vdpa_direct_mr *n;
 	LIST_HEAD(tmp);
@@ -354,9 +357,10 @@ static int add_direct_chain(struct mlx5_vdpa_dev *mvdev, u64 start, u64 size, u8
  * indirect memory key that provides access to the enitre address space given
  * by iotlb.
  */
-static int create_user_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb)
+static int create_user_mr(struct mlx5_vdpa_dev *mvdev,
+			  struct mlx5_vdpa_mr *mr,
+			  struct vhost_iotlb *iotlb)
 {
-	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 	struct mlx5_vdpa_direct_mr *dmr;
 	struct mlx5_vdpa_direct_mr *n;
 	struct vhost_iotlb_map *map;
@@ -384,7 +388,7 @@ static int create_user_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb
 								       LOG_MAX_KLM_SIZE);
 					mr->num_klms += nnuls;
 				}
-				err = add_direct_chain(mvdev, ps, pe - ps, pperm, iotlb);
+				err = add_direct_chain(mvdev, mr, ps, pe - ps, pperm, iotlb);
 				if (err)
 					goto err_chain;
 			}
@@ -393,7 +397,7 @@ static int create_user_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb
 			pperm = map->perm;
 		}
 	}
-	err = add_direct_chain(mvdev, ps, pe - ps, pperm, iotlb);
+	err = add_direct_chain(mvdev, mr, ps, pe - ps, pperm, iotlb);
 	if (err)
 		goto err_chain;
 
@@ -489,13 +493,8 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr
 	}
 }
 
-static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
+static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
 {
-	struct mlx5_vdpa_mr *mr = &mvdev->mr;
-
-	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
-		return;
-
 	if (!mr->initialized)
 		return;
 
@@ -507,38 +506,33 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid
 	mr->initialized = false;
 }
 
-void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
+void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
+			  struct mlx5_vdpa_mr *mr)
 {
-	struct mlx5_vdpa_mr *mr = &mvdev->mr;
-
 	mutex_lock(&mr->mkey_mtx);
 
-	_mlx5_vdpa_destroy_mr(mvdev, asid);
+	_mlx5_vdpa_destroy_mr(mvdev, mr);
 
 	mutex_unlock(&mr->mkey_mtx);
 }
 
 void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
 {
-	mlx5_vdpa_destroy_mr(mvdev, mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]);
+	mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
 	prune_iotlb(mvdev);
 }
 
 static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
-				struct vhost_iotlb *iotlb,
-				unsigned int asid)
+				struct mlx5_vdpa_mr *mr,
+				struct vhost_iotlb *iotlb)
 {
-	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 	int err;
 
-	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
-		return 0;
-
 	if (mr->initialized)
 		return 0;
 
 	if (iotlb)
-		err = create_user_mr(mvdev, iotlb);
+		err = create_user_mr(mvdev, mr, iotlb);
 	else
 		err = create_dma_mr(mvdev, mr);
 
@@ -550,13 +544,14 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
 	return 0;
 }
 
-int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
-			unsigned int asid)
+int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
+			struct mlx5_vdpa_mr *mr,
+			struct vhost_iotlb *iotlb)
 {
 	int err;
 
 	mutex_lock(&mvdev->mr.mkey_mtx);
-	err = _mlx5_vdpa_create_mr(mvdev, iotlb, asid);
+	err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
 	mutex_unlock(&mvdev->mr.mkey_mtx);
 	return err;
 }
@@ -574,7 +569,7 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io
 		*change_map = true;
 	}
 	if (!*change_map)
-		err = _mlx5_vdpa_create_mr(mvdev, iotlb, asid);
+		err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
 	mutex_unlock(&mr->mkey_mtx);
 
 	return err;
@@ -603,7 +598,7 @@ int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
 {
 	int err;
 
-	err = mlx5_vdpa_create_mr(mvdev, NULL, 0);
+	err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, NULL);
 	if (err)
 		return err;
 
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index ab196c43694c..256fdd80c321 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2644,8 +2644,8 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 		goto err_mr;
 
 	teardown_driver(ndev);
-	mlx5_vdpa_destroy_mr(mvdev, asid);
-	err = mlx5_vdpa_create_mr(mvdev, iotlb, asid);
+	mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
+	err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, iotlb);
 	if (err)
 		goto err_mr;
 
@@ -2660,7 +2660,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 	return 0;
 
 err_setup:
-	mlx5_vdpa_destroy_mr(mvdev, asid);
+	mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
 err_mr:
 	return err;
 }
@@ -2878,6 +2878,9 @@ static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 	bool change_map;
 	int err;
 
+	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
+		goto end;
+
 	err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map, asid);
 	if (err) {
 		mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
@@ -2890,6 +2893,7 @@ static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			return err;
 	}
 
+end:
 	return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
 }
 
-- 
2.41.0

[PATCH vhost v4 11/16] vdpa/mlx5: Move mr mutex out of mr struct

[Dragos Tatulea]

The mutex is named like it is supposed to protect only the mkey but in
reality it is a global lock for all mr resources.

Shift the mutex to it's rightful location (struct mlx5_vdpa_dev) and
give it a more appropriate name.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  4 ++--
 drivers/vdpa/mlx5/core/mr.c        | 13 +++++++------
 drivers/vdpa/mlx5/core/resources.c |  6 +++---
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index 01d4ee58ccb1..9c6ac42c21e1 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -34,8 +34,6 @@ struct mlx5_vdpa_mr {
 	/* state of dvq mr */
 	bool initialized;
 
-	/* serialize mkey creation and destruction */
-	struct mutex mkey_mtx;
 	bool user_mr;
 };
 
@@ -94,6 +92,8 @@ struct mlx5_vdpa_dev {
 	u32 generation;
 
 	struct mlx5_vdpa_mr mr;
+	/* serialize mr access */
+	struct mutex mr_mtx;
 	struct mlx5_control_vq cvq;
 	struct workqueue_struct *wq;
 	unsigned int group2asid[MLX5_VDPA_NUMVQ_GROUPS];
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 6f29e8eaabb1..abd6a6fb122f 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -509,11 +509,11 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
 			  struct mlx5_vdpa_mr *mr)
 {
-	mutex_lock(&mr->mkey_mtx);
+	mutex_lock(&mvdev->mr_mtx);
 
 	_mlx5_vdpa_destroy_mr(mvdev, mr);
 
-	mutex_unlock(&mr->mkey_mtx);
+	mutex_unlock(&mvdev->mr_mtx);
 }
 
 void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
@@ -550,9 +550,10 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
 {
 	int err;
 
-	mutex_lock(&mvdev->mr.mkey_mtx);
+	mutex_lock(&mvdev->mr_mtx);
 	err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
-	mutex_unlock(&mvdev->mr.mkey_mtx);
+	mutex_unlock(&mvdev->mr_mtx);
+
 	return err;
 }
 
@@ -563,14 +564,14 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io
 	int err = 0;
 
 	*change_map = false;
-	mutex_lock(&mr->mkey_mtx);
+	mutex_lock(&mvdev->mr_mtx);
 	if (mr->initialized) {
 		mlx5_vdpa_info(mvdev, "memory map update\n");
 		*change_map = true;
 	}
 	if (!*change_map)
 		err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
-	mutex_unlock(&mr->mkey_mtx);
+	mutex_unlock(&mvdev->mr_mtx);
 
 	return err;
 }
diff --git a/drivers/vdpa/mlx5/core/resources.c b/drivers/vdpa/mlx5/core/resources.c
index d5a59c9035fb..5c5a41b64bfc 100644
--- a/drivers/vdpa/mlx5/core/resources.c
+++ b/drivers/vdpa/mlx5/core/resources.c
@@ -256,7 +256,7 @@ int mlx5_vdpa_alloc_resources(struct mlx5_vdpa_dev *mvdev)
 		mlx5_vdpa_warn(mvdev, "resources already allocated\n");
 		return -EINVAL;
 	}
-	mutex_init(&mvdev->mr.mkey_mtx);
+	mutex_init(&mvdev->mr_mtx);
 	res->uar = mlx5_get_uars_page(mdev);
 	if (IS_ERR(res->uar)) {
 		err = PTR_ERR(res->uar);
@@ -301,7 +301,7 @@ int mlx5_vdpa_alloc_resources(struct mlx5_vdpa_dev *mvdev)
 err_uctx:
 	mlx5_put_uars_page(mdev, res->uar);
 err_uars:
-	mutex_destroy(&mvdev->mr.mkey_mtx);
+	mutex_destroy(&mvdev->mr_mtx);
 	return err;
 }
 
@@ -318,6 +318,6 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev *mvdev)
 	dealloc_pd(mvdev, res->pdn, res->uid);
 	destroy_uctx(mvdev, res->uid);
 	mlx5_put_uars_page(mvdev->mdev, res->uar);
-	mutex_destroy(&mvdev->mr.mkey_mtx);
+	mutex_destroy(&mvdev->mr_mtx);
 	res->valid = false;
 }
-- 
2.41.0

[PATCH vhost v4 12/16] vdpa/mlx5: Improve mr update flow

[Dragos Tatulea]

The current flow for updating an mr works directly on mvdev->mr which
makes it cumbersome to handle multiple new mr structs.

This patch makes the flow more straightforward by having
mlx5_vdpa_create_mr return a new mr which will update the old mr (if
any). The old mr will be deleted and unlinked from mvdev. For the case
when the iotlb is empty (not NULL), the old mr will be cleared.

This change paves the way for adding mrs for different ASIDs.

The initialized bool is no longer needed as mr is now a pointer in the
mlx5_vdpa_dev struct which will be NULL when not initialized.

Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h | 14 +++--
 drivers/vdpa/mlx5/core/mr.c        | 87 ++++++++++++++++--------------
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 53 +++++++++---------
 3 files changed, 82 insertions(+), 72 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index 9c6ac42c21e1..bbe4335106bd 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -31,8 +31,6 @@ struct mlx5_vdpa_mr {
 	struct list_head head;
 	unsigned long num_directs;
 	unsigned long num_klms;
-	/* state of dvq mr */
-	bool initialized;
 
 	bool user_mr;
 };
@@ -91,7 +89,7 @@ struct mlx5_vdpa_dev {
 	u16 max_idx;
 	u32 generation;
 
-	struct mlx5_vdpa_mr mr;
+	struct mlx5_vdpa_mr *mr;
 	/* serialize mr access */
 	struct mutex mr_mtx;
 	struct mlx5_control_vq cvq;
@@ -114,14 +112,14 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev *mvdev);
 int mlx5_vdpa_create_mkey(struct mlx5_vdpa_dev *mvdev, u32 *mkey, u32 *in,
 			  int inlen);
 int mlx5_vdpa_destroy_mkey(struct mlx5_vdpa_dev *mvdev, u32 mkey);
-int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
-			     bool *change_map, unsigned int asid);
-int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
-			struct mlx5_vdpa_mr *mr,
-			struct vhost_iotlb *iotlb);
+struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
+					 struct vhost_iotlb *iotlb);
 void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
 			  struct mlx5_vdpa_mr *mr);
+void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
+			 struct mlx5_vdpa_mr *mr,
+			 unsigned int asid);
 int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 				struct vhost_iotlb *iotlb,
 				unsigned int asid);
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index abd6a6fb122f..00eff5a07152 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -495,30 +495,51 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr
 
 static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
 {
-	if (!mr->initialized)
-		return;
-
 	if (mr->user_mr)
 		destroy_user_mr(mvdev, mr);
 	else
 		destroy_dma_mr(mvdev, mr);
-
-	mr->initialized = false;
 }
 
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
 			  struct mlx5_vdpa_mr *mr)
 {
+	if (!mr)
+		return;
+
 	mutex_lock(&mvdev->mr_mtx);
 
 	_mlx5_vdpa_destroy_mr(mvdev, mr);
 
+	if (mvdev->mr == mr)
+		mvdev->mr = NULL;
+
+	mutex_unlock(&mvdev->mr_mtx);
+
+	kfree(mr);
+}
+
+void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
+			 struct mlx5_vdpa_mr *new_mr,
+			 unsigned int asid)
+{
+	struct mlx5_vdpa_mr *old_mr = mvdev->mr;
+
+	mutex_lock(&mvdev->mr_mtx);
+
+	mvdev->mr = new_mr;
+	if (old_mr) {
+		_mlx5_vdpa_destroy_mr(mvdev, old_mr);
+		kfree(old_mr);
+	}
+
 	mutex_unlock(&mvdev->mr_mtx);
+
 }
 
 void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
 {
-	mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
+	mlx5_vdpa_destroy_mr(mvdev, mvdev->mr);
 	prune_iotlb(mvdev);
 }
 
@@ -528,52 +549,36 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
 {
 	int err;
 
-	if (mr->initialized)
-		return 0;
-
 	if (iotlb)
 		err = create_user_mr(mvdev, mr, iotlb);
 	else
 		err = create_dma_mr(mvdev, mr);
 
-	if (err)
-		return err;
-
-	mr->initialized = true;
-
-	return 0;
+	return err;
 }
 
-int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
-			struct mlx5_vdpa_mr *mr,
-			struct vhost_iotlb *iotlb)
+struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
+					 struct vhost_iotlb *iotlb)
 {
+	struct mlx5_vdpa_mr *mr;
 	int err;
 
+	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
+	if (!mr)
+		return ERR_PTR(-ENOMEM);
+
 	mutex_lock(&mvdev->mr_mtx);
 	err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
 	mutex_unlock(&mvdev->mr_mtx);
 
-	return err;
-}
-
-int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
-			     bool *change_map, unsigned int asid)
-{
-	struct mlx5_vdpa_mr *mr = &mvdev->mr;
-	int err = 0;
+	if (err)
+		goto out_err;
 
-	*change_map = false;
-	mutex_lock(&mvdev->mr_mtx);
-	if (mr->initialized) {
-		mlx5_vdpa_info(mvdev, "memory map update\n");
-		*change_map = true;
-	}
-	if (!*change_map)
-		err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
-	mutex_unlock(&mvdev->mr_mtx);
+	return mr;
 
-	return err;
+out_err:
+	kfree(mr);
+	return ERR_PTR(err);
 }
 
 int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
@@ -597,11 +602,13 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 
 int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
 {
-	int err;
+	struct mlx5_vdpa_mr *mr;
 
-	err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, NULL);
-	if (err)
-		return err;
+	mr = mlx5_vdpa_create_mr(mvdev, NULL);
+	if (IS_ERR(mr))
+		return PTR_ERR(mr);
+
+	mlx5_vdpa_update_mr(mvdev, mr, 0);
 
 	return mlx5_vdpa_update_cvq_iotlb(mvdev, NULL, 0);
 }
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 256fdd80c321..7b878995b6aa 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -873,7 +873,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
 	MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
 	MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
-	MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr.mkey);
+	MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr->mkey);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
 	MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
@@ -2633,7 +2633,7 @@ static void restore_channels_info(struct mlx5_vdpa_net *ndev)
 }
 
 static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
-				struct vhost_iotlb *iotlb, unsigned int asid)
+				struct mlx5_vdpa_mr *new_mr, unsigned int asid)
 {
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	int err;
@@ -2641,27 +2641,18 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 	suspend_vqs(ndev);
 	err = save_channels_info(ndev);
 	if (err)
-		goto err_mr;
+		return err;
 
 	teardown_driver(ndev);
-	mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
-	err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, iotlb);
-	if (err)
-		goto err_mr;
+
+	mlx5_vdpa_update_mr(mvdev, new_mr, asid);
 
 	if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK) || mvdev->suspended)
-		goto err_mr;
+		return 0;
 
 	restore_channels_info(ndev);
 	err = setup_driver(mvdev);
-	if (err)
-		goto err_setup;
-
-	return 0;
 
-err_setup:
-	mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
-err_mr:
 	return err;
 }
 
@@ -2875,26 +2866,40 @@ static u32 mlx5_vdpa_get_generation(struct vdpa_device *vdev)
 static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 			unsigned int asid)
 {
-	bool change_map;
+	struct mlx5_vdpa_mr *new_mr;
 	int err;
 
 	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
 		goto end;
 
-	err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map, asid);
-	if (err) {
-		mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
-		return err;
+	if (vhost_iotlb_itree_first(iotlb, 0, U64_MAX)) {
+		new_mr = mlx5_vdpa_create_mr(mvdev, iotlb);
+		if (IS_ERR(new_mr)) {
+			err = PTR_ERR(new_mr);
+			mlx5_vdpa_warn(mvdev, "create map failed(%d)\n", err);
+			return err;
+		}
+	} else {
+		/* Empty iotlbs don't have an mr but will clear the previous mr. */
+		new_mr = NULL;
 	}
 
-	if (change_map) {
-		err = mlx5_vdpa_change_map(mvdev, iotlb, asid);
-		if (err)
-			return err;
+	if (!mvdev->mr) {
+		mlx5_vdpa_update_mr(mvdev, new_mr, asid);
+	} else {
+		err = mlx5_vdpa_change_map(mvdev, new_mr, asid);
+		if (err) {
+			mlx5_vdpa_warn(mvdev, "change map failed(%d)\n", err);
+			goto out_err;
+		}
 	}
 
 end:
 	return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
+
+out_err:
+	mlx5_vdpa_destroy_mr(mvdev, new_mr);
+	return err;
 }
 
 static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
-- 
2.41.0

[PATCH vhost v4 13/16] vdpa/mlx5: Introduce mr for vq descriptor

[Dragos Tatulea]

Introduce the vq descriptor group and mr per ASID. Until now
.set_map on ASID 1 was only updating the cvq iotlb. From now on it also
creates a mkey for it. The current patch doesn't use it but follow-up
patches will add hardware support for mapping the vq descriptors.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  5 +++--
 drivers/vdpa/mlx5/core/mr.c        | 14 +++++++++-----
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 20 +++++++++++++-------
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index bbe4335106bd..ae09296f4270 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -70,11 +70,12 @@ struct mlx5_vdpa_wq_ent {
 enum {
 	MLX5_VDPA_DATAVQ_GROUP,
 	MLX5_VDPA_CVQ_GROUP,
+	MLX5_VDPA_DATAVQ_DESC_GROUP,
 	MLX5_VDPA_NUMVQ_GROUPS
 };
 
 enum {
-	MLX5_VDPA_NUM_AS = MLX5_VDPA_NUMVQ_GROUPS
+	MLX5_VDPA_NUM_AS = 2
 };
 
 struct mlx5_vdpa_dev {
@@ -89,7 +90,7 @@ struct mlx5_vdpa_dev {
 	u16 max_idx;
 	u32 generation;
 
-	struct mlx5_vdpa_mr *mr;
+	struct mlx5_vdpa_mr *mr[MLX5_VDPA_NUM_AS];
 	/* serialize mr access */
 	struct mutex mr_mtx;
 	struct mlx5_control_vq cvq;
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 00eff5a07152..3dee6d9bed6b 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -511,8 +511,10 @@ void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
 
 	_mlx5_vdpa_destroy_mr(mvdev, mr);
 
-	if (mvdev->mr == mr)
-		mvdev->mr = NULL;
+	for (int i = 0; i < MLX5_VDPA_NUM_AS; i++) {
+		if (mvdev->mr[i] == mr)
+			mvdev->mr[i] = NULL;
+	}
 
 	mutex_unlock(&mvdev->mr_mtx);
 
@@ -523,11 +525,11 @@ void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
 			 struct mlx5_vdpa_mr *new_mr,
 			 unsigned int asid)
 {
-	struct mlx5_vdpa_mr *old_mr = mvdev->mr;
+	struct mlx5_vdpa_mr *old_mr = mvdev->mr[asid];
 
 	mutex_lock(&mvdev->mr_mtx);
 
-	mvdev->mr = new_mr;
+	mvdev->mr[asid] = new_mr;
 	if (old_mr) {
 		_mlx5_vdpa_destroy_mr(mvdev, old_mr);
 		kfree(old_mr);
@@ -539,7 +541,9 @@ void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
 
 void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
 {
-	mlx5_vdpa_destroy_mr(mvdev, mvdev->mr);
+	for (int i = 0; i < MLX5_VDPA_NUM_AS; i++)
+		mlx5_vdpa_destroy_mr(mvdev, mvdev->mr[i]);
+
 	prune_iotlb(mvdev);
 }
 
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 7b878995b6aa..ea76c0b4b78e 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -821,6 +821,8 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 {
 	int inlen = MLX5_ST_SZ_BYTES(create_virtio_net_q_in);
 	u32 out[MLX5_ST_SZ_DW(create_virtio_net_q_out)] = {};
+	struct mlx5_vdpa_dev *mvdev = &ndev->mvdev;
+	struct mlx5_vdpa_mr *vq_mr;
 	void *obj_context;
 	u16 mlx_features;
 	void *cmd_hdr;
@@ -873,7 +875,9 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
 	MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
 	MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
-	MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr->mkey);
+	vq_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]];
+	if (vq_mr)
+		MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, vq_mr->mkey);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
 	MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
@@ -2633,7 +2637,8 @@ static void restore_channels_info(struct mlx5_vdpa_net *ndev)
 }
 
 static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
-				struct mlx5_vdpa_mr *new_mr, unsigned int asid)
+				struct mlx5_vdpa_mr *new_mr,
+				unsigned int asid)
 {
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	int err;
@@ -2652,8 +2657,10 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 
 	restore_channels_info(ndev);
 	err = setup_driver(mvdev);
+	if (err)
+		return err;
 
-	return err;
+	return 0;
 }
 
 /* reslock must be held for this function */
@@ -2869,8 +2876,8 @@ static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 	struct mlx5_vdpa_mr *new_mr;
 	int err;
 
-	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
-		goto end;
+	if (asid >= MLX5_VDPA_NUM_AS)
+		return -EINVAL;
 
 	if (vhost_iotlb_itree_first(iotlb, 0, U64_MAX)) {
 		new_mr = mlx5_vdpa_create_mr(mvdev, iotlb);
@@ -2884,7 +2891,7 @@ static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 		new_mr = NULL;
 	}
 
-	if (!mvdev->mr) {
+	if (!mvdev->mr[asid]) {
 		mlx5_vdpa_update_mr(mvdev, new_mr, asid);
 	} else {
 		err = mlx5_vdpa_change_map(mvdev, new_mr, asid);
@@ -2894,7 +2901,6 @@ static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb,
 		}
 	}
 
-end:
 	return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
 
 out_err:
-- 
2.41.0

[PATCH vhost v4 14/16] vdpa/mlx5: Enable hw support for vq descriptor mapping

[Dragos Tatulea]

Vq descriptor mappings are supported in hardware by filling in an
additional mkey which contains the descriptor mappings to the hw vq.

A previous patch in this series added support for hw mkey (mr) creation
for ASID 1.

This patch fills in both the vq data and vq descriptor mkeys based on
group ASID mapping.

The feature is signaled to the vdpa core through the presence of the
.get_vq_desc_group op.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 24 +++++++++++++++++++++++-
 include/linux/mlx5/mlx5_ifc_vdpa.h |  7 ++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index ea76c0b4b78e..87dd0ba76899 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -823,6 +823,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	u32 out[MLX5_ST_SZ_DW(create_virtio_net_q_out)] = {};
 	struct mlx5_vdpa_dev *mvdev = &ndev->mvdev;
 	struct mlx5_vdpa_mr *vq_mr;
+	struct mlx5_vdpa_mr *vq_desc_mr;
 	void *obj_context;
 	u16 mlx_features;
 	void *cmd_hdr;
@@ -878,6 +879,11 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	vq_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]];
 	if (vq_mr)
 		MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, vq_mr->mkey);
+
+	vq_desc_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_DESC_GROUP]];
+	if (vq_desc_mr && MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, desc_group_mkey_supported))
+		MLX5_SET(virtio_q, vq_ctx, desc_group_mkey, vq_desc_mr->mkey);
+
 	MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
 	MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
@@ -2265,6 +2271,16 @@ static u32 mlx5_vdpa_get_vq_group(struct vdpa_device *vdev, u16 idx)
 	return MLX5_VDPA_DATAVQ_GROUP;
 }
 
+static u32 mlx5_vdpa_get_vq_desc_group(struct vdpa_device *vdev, u16 idx)
+{
+	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+
+	if (is_ctrl_vq_idx(mvdev, idx))
+		return MLX5_VDPA_CVQ_GROUP;
+
+	return MLX5_VDPA_DATAVQ_DESC_GROUP;
+}
+
 static u64 mlx_to_vritio_features(u16 dev_features)
 {
 	u64 result = 0;
@@ -3165,6 +3181,7 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
 	.get_vq_irq = mlx5_get_vq_irq,
 	.get_vq_align = mlx5_vdpa_get_vq_align,
 	.get_vq_group = mlx5_vdpa_get_vq_group,
+	.get_vq_desc_group = mlx5_vdpa_get_vq_desc_group, /* Op disabled if not supported. */
 	.get_device_features = mlx5_vdpa_get_device_features,
 	.set_driver_features = mlx5_vdpa_set_driver_features,
 	.get_driver_features = mlx5_vdpa_get_driver_features,
@@ -3263,6 +3280,7 @@ struct mlx5_vdpa_mgmtdev {
 	struct vdpa_mgmt_dev mgtdev;
 	struct mlx5_adev *madev;
 	struct mlx5_vdpa_net *ndev;
+	struct vdpa_config_ops vdpa_ops;
 };
 
 static int config_func_mtu(struct mlx5_core_dev *mdev, u16 mtu)
@@ -3376,7 +3394,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 		max_vqs = 2;
 	}
 
-	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
+	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mgtdev->vdpa_ops,
 				 MLX5_VDPA_NUMVQ_GROUPS, MLX5_VDPA_NUM_AS, name, false);
 	if (IS_ERR(ndev))
 		return PTR_ERR(ndev);
@@ -3551,6 +3569,10 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 		MLX5_CAP_DEV_VDPA_EMULATION(mdev, max_num_virtio_queues) + 1;
 	mgtdev->mgtdev.supported_features = get_supported_features(mdev);
 	mgtdev->madev = madev;
+	mgtdev->vdpa_ops = mlx5_vdpa_ops;
+
+	if (!MLX5_CAP_DEV_VDPA_EMULATION(mdev, desc_group_mkey_supported))
+		mgtdev->vdpa_ops.get_vq_desc_group = NULL;
 
 	err = vdpa_mgmtdev_register(&mgtdev->mgtdev);
 	if (err)
diff --git a/include/linux/mlx5/mlx5_ifc_vdpa.h b/include/linux/mlx5/mlx5_ifc_vdpa.h
index 9becdc3fa503..b86d51a855f6 100644
--- a/include/linux/mlx5/mlx5_ifc_vdpa.h
+++ b/include/linux/mlx5/mlx5_ifc_vdpa.h
@@ -74,7 +74,11 @@ struct mlx5_ifc_virtio_q_bits {
 	u8    reserved_at_320[0x8];
 	u8    pd[0x18];
 
-	u8    reserved_at_340[0xc0];
+	u8    reserved_at_340[0x20];
+
+	u8    desc_group_mkey[0x20];
+
+	u8    reserved_at_380[0x80];
 };
 
 struct mlx5_ifc_virtio_net_q_object_bits {
@@ -141,6 +145,7 @@ enum {
 	MLX5_VIRTQ_MODIFY_MASK_STATE                    = (u64)1 << 0,
 	MLX5_VIRTQ_MODIFY_MASK_DIRTY_BITMAP_PARAMS      = (u64)1 << 3,
 	MLX5_VIRTQ_MODIFY_MASK_DIRTY_BITMAP_DUMP_ENABLE = (u64)1 << 4,
+	MLX5_VIRTQ_MODIFY_MASK_DESC_GROUP_MKEY          = (u64)1 << 14,
 };
 
 enum {
-- 
2.41.0

[PATCH vhost v4 15/16] vdpa/mlx5: Make iotlb helper functions more generic

[Dragos Tatulea]

They will be used in a follow-up patch.

For dup_iotlb, avoid the src == dst case. This is an error.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mr.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 3dee6d9bed6b..4a3df865df40 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -454,20 +454,23 @@ static void destroy_dma_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
 	mlx5_vdpa_destroy_mkey(mvdev, mr->mkey);
 }
 
-static int dup_iotlb(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *src)
+static int dup_iotlb(struct vhost_iotlb *dst, struct vhost_iotlb *src)
 {
 	struct vhost_iotlb_map *map;
 	u64 start = 0, last = ULLONG_MAX;
 	int err;
 
+	if (dst == src)
+		return -EINVAL;
+
 	if (!src) {
-		err = vhost_iotlb_add_range(mvdev->cvq.iotlb, start, last, start, VHOST_ACCESS_RW);
+		err = vhost_iotlb_add_range(dst, start, last, start, VHOST_ACCESS_RW);
 		return err;
 	}
 
 	for (map = vhost_iotlb_itree_first(src, start, last); map;
 		map = vhost_iotlb_itree_next(map, start, last)) {
-		err = vhost_iotlb_add_range(mvdev->cvq.iotlb, map->start, map->last,
+		err = vhost_iotlb_add_range(dst, map->start, map->last,
 					    map->addr, map->perm);
 		if (err)
 			return err;
@@ -475,9 +478,9 @@ static int dup_iotlb(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *src)
 	return 0;
 }
 
-static void prune_iotlb(struct mlx5_vdpa_dev *mvdev)
+static void prune_iotlb(struct vhost_iotlb *iotlb)
 {
-	vhost_iotlb_del_range(mvdev->cvq.iotlb, 0, ULLONG_MAX);
+	vhost_iotlb_del_range(iotlb, 0, ULLONG_MAX);
 }
 
 static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
@@ -544,7 +547,7 @@ void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
 	for (int i = 0; i < MLX5_VDPA_NUM_AS; i++)
 		mlx5_vdpa_destroy_mr(mvdev, mvdev->mr[i]);
 
-	prune_iotlb(mvdev);
+	prune_iotlb(mvdev->cvq.iotlb);
 }
 
 static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
@@ -596,8 +599,8 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 
 	spin_lock(&mvdev->cvq.iommu_lock);
 
-	prune_iotlb(mvdev);
-	err = dup_iotlb(mvdev, iotlb);
+	prune_iotlb(mvdev->cvq.iotlb);
+	err = dup_iotlb(mvdev->cvq.iotlb, iotlb);
 
 	spin_unlock(&mvdev->cvq.iommu_lock);
 
-- 
2.41.0

[PATCH vhost v4 16/16] vdpa/mlx5: Update cvq iotlb mapping on ASID change

[Dragos Tatulea]

For the following sequence:
- cvq group is in ASID 0
- .set_map(1, cvq_iotlb)
- .set_group_asid(cvq_group, 1)

... the cvq mapping from ASID 0 will be used. This is not always correct
behaviour.

This patch adds support for the above mentioned flow by saving the iotlb
on each .set_map and updating the cvq iotlb with it on a cvq group change.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  2 ++
 drivers/vdpa/mlx5/core/mr.c        | 26 ++++++++++++++++++++++++++
 drivers/vdpa/mlx5/net/mlx5_vnet.c  |  9 ++++++++-
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index ae09296f4270..db988ced5a5d 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -32,6 +32,8 @@ struct mlx5_vdpa_mr {
 	unsigned long num_directs;
 	unsigned long num_klms;
 
+	struct vhost_iotlb *iotlb;
+
 	bool user_mr;
 };
 
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 4a3df865df40..66530e28f327 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -502,6 +502,8 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_
 		destroy_user_mr(mvdev, mr);
 	else
 		destroy_dma_mr(mvdev, mr);
+
+	vhost_iotlb_free(mr->iotlb);
 }
 
 void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
@@ -561,6 +563,30 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
 	else
 		err = create_dma_mr(mvdev, mr);
 
+	if (err)
+		return err;
+
+	mr->iotlb = vhost_iotlb_alloc(0, 0);
+	if (!mr->iotlb) {
+		err = -ENOMEM;
+		goto err_mr;
+	}
+
+	err = dup_iotlb(mr->iotlb, iotlb);
+	if (err)
+		goto err_iotlb;
+
+	return 0;
+
+err_iotlb:
+	vhost_iotlb_free(mr->iotlb);
+
+err_mr:
+	if (iotlb)
+		destroy_user_mr(mvdev, mr);
+	else
+		destroy_dma_mr(mvdev, mr);
+
 	return err;
 }
 
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 87dd0ba76899..5774f4adb7c4 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -3159,12 +3159,19 @@ static int mlx5_set_group_asid(struct vdpa_device *vdev, u32 group,
 			       unsigned int asid)
 {
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+	int err = 0;
 
 	if (group >= MLX5_VDPA_NUMVQ_GROUPS)
 		return -EINVAL;
 
 	mvdev->group2asid[group] = asid;
-	return 0;
+
+	mutex_lock(&mvdev->mr_mtx);
+	if (group == MLX5_VDPA_CVQ_GROUP && mvdev->mr[asid])
+		err = mlx5_vdpa_update_cvq_iotlb(mvdev, mvdev->mr[asid]->iotlb, asid);
+	mutex_unlock(&mvdev->mr_mtx);
+
+	return err;
 }
 
 static const struct vdpa_config_ops mlx5_vdpa_ops = {
-- 
2.41.0

Re: [PATCH vhost v4 12/16] vdpa/mlx5: Improve mr update flow

[Dragos Tatulea]

On Wed, 2023-10-18 at 20:14 +0300, Dragos Tatulea wrote:
> The current flow for updating an mr works directly on mvdev->mr which
> makes it cumbersome to handle multiple new mr structs.
> 
> This patch makes the flow more straightforward by having
> mlx5_vdpa_create_mr return a new mr which will update the old mr (if
> any). The old mr will be deleted and unlinked from mvdev. For the case
> when the iotlb is empty (not NULL), the old mr will be cleared.
> 
> This change paves the way for adding mrs for different ASIDs.
> 
> The initialized bool is no longer needed as mr is now a pointer in the
> mlx5_vdpa_dev struct which will be NULL when not initialized.
> 
> Acked-by: Eugenio Pérez <eperezma@redhat.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> ---
>  drivers/vdpa/mlx5/core/mlx5_vdpa.h | 14 +++--
>  drivers/vdpa/mlx5/core/mr.c        | 87 ++++++++++++++++--------------
>  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 53 +++++++++---------
>  3 files changed, 82 insertions(+), 72 deletions(-)
> 
> diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> index 9c6ac42c21e1..bbe4335106bd 100644
> --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> @@ -31,8 +31,6 @@ struct mlx5_vdpa_mr {
>         struct list_head head;
>         unsigned long num_directs;
>         unsigned long num_klms;
> -       /* state of dvq mr */
> -       bool initialized;
>  
>         bool user_mr;
>  };
> @@ -91,7 +89,7 @@ struct mlx5_vdpa_dev {
>         u16 max_idx;
>         u32 generation;
>  
> -       struct mlx5_vdpa_mr mr;
> +       struct mlx5_vdpa_mr *mr;
>         /* serialize mr access */
>         struct mutex mr_mtx;
>         struct mlx5_control_vq cvq;
> @@ -114,14 +112,14 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev
> *mvdev);
>  int mlx5_vdpa_create_mkey(struct mlx5_vdpa_dev *mvdev, u32 *mkey, u32 *in,
>                           int inlen);
>  int mlx5_vdpa_destroy_mkey(struct mlx5_vdpa_dev *mvdev, u32 mkey);
> -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> *iotlb,
> -                            bool *change_map, unsigned int asid);
> -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> -                       struct mlx5_vdpa_mr *mr,
> -                       struct vhost_iotlb *iotlb);
> +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> +                                        struct vhost_iotlb *iotlb);
>  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
>  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
>                           struct mlx5_vdpa_mr *mr);
> +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> +                        struct mlx5_vdpa_mr *mr,
> +                        unsigned int asid);
>  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
>                                 struct vhost_iotlb *iotlb,
>                                 unsigned int asid);
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index abd6a6fb122f..00eff5a07152 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -495,30 +495,51 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev,
> struct mlx5_vdpa_mr *mr
>  
>  static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct
> mlx5_vdpa_mr *mr)
>  {
> -       if (!mr->initialized)
> -               return;
> -
>         if (mr->user_mr)
>                 destroy_user_mr(mvdev, mr);
>         else
>                 destroy_dma_mr(mvdev, mr);
> -
> -       mr->initialized = false;
>  }
>  
>  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
>                           struct mlx5_vdpa_mr *mr)
>  {
> +       if (!mr)
> +               return;
> +
>         mutex_lock(&mvdev->mr_mtx);
>  
>         _mlx5_vdpa_destroy_mr(mvdev, mr);
>  
> +       if (mvdev->mr == mr)
> +               mvdev->mr = NULL;
> +
> +       mutex_unlock(&mvdev->mr_mtx);
> +
> +       kfree(mr);
> +}
> +
> +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> +                        struct mlx5_vdpa_mr *new_mr,
> +                        unsigned int asid)
> +{
> +       struct mlx5_vdpa_mr *old_mr = mvdev->mr;
> +
> +       mutex_lock(&mvdev->mr_mtx);
> +
> +       mvdev->mr = new_mr;
> +       if (old_mr) {
> +               _mlx5_vdpa_destroy_mr(mvdev, old_mr);
> +               kfree(old_mr);
> +       }
> +
>         mutex_unlock(&mvdev->mr_mtx);
> +
>  }
>  
>  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
>  {
> -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> +       mlx5_vdpa_destroy_mr(mvdev, mvdev->mr);
>         prune_iotlb(mvdev);
>  }
>  
> @@ -528,52 +549,36 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev
> *mvdev,
>  {
>         int err;
>  
> -       if (mr->initialized)
> -               return 0;
> -
>         if (iotlb)
>                 err = create_user_mr(mvdev, mr, iotlb);
>         else
>                 err = create_dma_mr(mvdev, mr);
>  
> -       if (err)
> -               return err;
> -
> -       mr->initialized = true;
> -
> -       return 0;
> +       return err;
>  }
>  
> -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> -                       struct mlx5_vdpa_mr *mr,
> -                       struct vhost_iotlb *iotlb)
> +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> +                                        struct vhost_iotlb *iotlb)
>  {
> +       struct mlx5_vdpa_mr *mr;
>         int err;
>  
> +       mr = kzalloc(sizeof(*mr), GFP_KERNEL);
> +       if (!mr)
> +               return ERR_PTR(-ENOMEM);
> +
>         mutex_lock(&mvdev->mr_mtx);
>         err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
>         mutex_unlock(&mvdev->mr_mtx);
>  
> -       return err;
> -}
> -
> -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> *iotlb,
> -                            bool *change_map, unsigned int asid)
> -{
> -       struct mlx5_vdpa_mr *mr = &mvdev->mr;
> -       int err = 0;
> +       if (err)
> +               goto out_err;
>  
> -       *change_map = false;
> -       mutex_lock(&mvdev->mr_mtx);
> -       if (mr->initialized) {
> -               mlx5_vdpa_info(mvdev, "memory map update\n");
> -               *change_map = true;
> -       }
> -       if (!*change_map)
> -               err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> -       mutex_unlock(&mvdev->mr_mtx);
> +       return mr;
>  
> -       return err;
> +out_err:
> +       kfree(mr);
> +       return ERR_PTR(err);
>  }
>  
>  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> @@ -597,11 +602,13 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev
> *mvdev,
>  
>  int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
>  {
> -       int err;
> +       struct mlx5_vdpa_mr *mr;
>  
> -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, NULL);
> -       if (err)
> -               return err;
> +       mr = mlx5_vdpa_create_mr(mvdev, NULL);
> +       if (IS_ERR(mr))
> +               return PTR_ERR(mr);
> +
> +       mlx5_vdpa_update_mr(mvdev, mr, 0);
>  
>         return mlx5_vdpa_update_cvq_iotlb(mvdev, NULL, 0);
>  }
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 256fdd80c321..7b878995b6aa 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -873,7 +873,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev,
> struct mlx5_vdpa_virtque
>         MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
>         MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
>         MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
> -       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr.mkey);
> +       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr->mkey);
>         MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
>         MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
>         MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
> @@ -2633,7 +2633,7 @@ static void restore_channels_info(struct mlx5_vdpa_net
> *ndev)
>  }
>  
>  static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
> -                               struct vhost_iotlb *iotlb, unsigned int asid)
> +                               struct mlx5_vdpa_mr *new_mr, unsigned int
> asid)
>  {
>         struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>         int err;
> @@ -2641,27 +2641,18 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev
> *mvdev,
>         suspend_vqs(ndev);
>         err = save_channels_info(ndev);
>         if (err)
> -               goto err_mr;
> +               return err;
>  
>         teardown_driver(ndev);
> -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, iotlb);
> -       if (err)
> -               goto err_mr;
> +
> +       mlx5_vdpa_update_mr(mvdev, new_mr, asid);
>  
>         if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK) || mvdev->suspended)
> -               goto err_mr;
> +               return 0;
>  
>         restore_channels_info(ndev);
>         err = setup_driver(mvdev);
> -       if (err)
> -               goto err_setup;
> -
> -       return 0;
>  
> -err_setup:
> -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> -err_mr:
>         return err;
>  }
>  
> @@ -2875,26 +2866,40 @@ static u32 mlx5_vdpa_get_generation(struct vdpa_device
> *vdev)
>  static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> *iotlb,
>                         unsigned int asid)
>  {
> -       bool change_map;
> +       struct mlx5_vdpa_mr *new_mr;
>         int err;
>  
>         if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
>                 goto end;
>  
> -       err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map, asid);
> -       if (err) {
> -               mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
> -               return err;
> +       if (vhost_iotlb_itree_first(iotlb, 0, U64_MAX)) {
> +               new_mr = mlx5_vdpa_create_mr(mvdev, iotlb);
> +               if (IS_ERR(new_mr)) {
> +                       err = PTR_ERR(new_mr);
> +                       mlx5_vdpa_warn(mvdev, "create map failed(%d)\n", err);
> +                       return err;
> +               }
> +       } else {
> +               /* Empty iotlbs don't have an mr but will clear the previous
> mr. */
> +               new_mr = NULL;
>         }
Hi Jason and/or Eugenio, could you have a quick look at this part of the patch
that changed please?

Thanks,
Dragos
>  
> -       if (change_map) {
> -               err = mlx5_vdpa_change_map(mvdev, iotlb, asid);
> -               if (err)
> -                       return err;
> +       if (!mvdev->mr) {
> +               mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> +       } else {
> +               err = mlx5_vdpa_change_map(mvdev, new_mr, asid);
> +               if (err) {
> +                       mlx5_vdpa_warn(mvdev, "change map failed(%d)\n", err);
> +                       goto out_err;
> +               }
>         }
>  
>  end:
>         return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
> +
> +out_err:
> +       mlx5_vdpa_destroy_mr(mvdev, new_mr);
> +       return err;
>  }
>  
>  static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,

Re: [PATCH vhost v4 00/16] vdpa: Add support for vq descriptor mappings

[Michael S. Tsirkin]

On Wed, Oct 18, 2023 at 08:14:39PM +0300, Dragos Tatulea wrote:
> This patch series adds support for vq descriptor table mappings which
> are used to improve vdpa live migration downtime. The improvement comes
> from using smaller mappings which take less time to create and destroy
> in hw.
> 
> The first part adds the vdpa core changes from Si-Wei [0].
> 
> The second part adds support in mlx5_vdpa:
> - Refactor the mr code to be able to cleanly add descriptor mappings.
> - Add hardware descriptor mr support.
> - Properly update iotlb for cvq during ASID switch.
> 
> Changes in v4:
> 
> - Improved the handling of empty iotlbs. See mlx5_vdpa_change_map
>   section in patch "12/16 vdpa/mlx5: Improve mr upate flow".
> - Fixed a invalid usage of desc_group_mkey hw vq field when the
>   capability is not there. See patch
>   "15/16 vdpa/mlx5: Enable hw support for vq descriptor map".

At this point, whether this patchset makes it in 6.7 will largely depend
on how many rcs there are in 6.6, so it can get some time in next.


> Changes in v3:
> 
> - dup_iotlb now checks for src == dst case and returns an error.
> - Renamed iotlb parameter in dup_iotlb to dst.
> - Removed a redundant check of the asid value.
> - Fixed a commit message.
> - mx5_ifc.h patch has been applied to mlx5-vhost tree. When applying
>   this series please pull from that tree first.
> 
> Changes in v2:
> 
> - The "vdpa/mlx5: Enable hw support for vq descriptor mapping" change
>   was split off into two patches to avoid merge conflicts into the tree
>   of Linus.
> 
>   The first patch contains only changes for mlx5_ifc.h. This must be
>   applied into the mlx5-vdpa tree [1] first. Once this patch is applied
>   on mlx5-vdpa, the change has to be pulled fom mlx5-vdpa into the vhost
>   tree and only then the remaining patches can be applied.
> 
> [0] https://lore.kernel.org/virtualization/1694248959-13369-1-git-send-email-si-wei.liu@oracle.com
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-vhost
> 
> Dragos Tatulea (13):
>   vdpa/mlx5: Expose descriptor group mkey hw capability
>   vdpa/mlx5: Create helper function for dma mappings
>   vdpa/mlx5: Decouple cvq iotlb handling from hw mapping code
>   vdpa/mlx5: Take cvq iotlb lock during refresh
>   vdpa/mlx5: Collapse "dvq" mr add/delete functions
>   vdpa/mlx5: Rename mr destroy functions
>   vdpa/mlx5: Allow creation/deletion of any given mr struct
>   vdpa/mlx5: Move mr mutex out of mr struct
>   vdpa/mlx5: Improve mr update flow
>   vdpa/mlx5: Introduce mr for vq descriptor
>   vdpa/mlx5: Enable hw support for vq descriptor mapping
>   vdpa/mlx5: Make iotlb helper functions more generic
>   vdpa/mlx5: Update cvq iotlb mapping on ASID change
> 
> Si-Wei Liu (3):
>   vdpa: introduce dedicated descriptor group for virtqueue
>   vhost-vdpa: introduce descriptor group backend feature
>   vhost-vdpa: uAPI to get dedicated descriptor group id
> 
>  drivers/vdpa/mlx5/core/mlx5_vdpa.h |  31 +++--
>  drivers/vdpa/mlx5/core/mr.c        | 194 ++++++++++++++++-------------
>  drivers/vdpa/mlx5/core/resources.c |   6 +-
>  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 105 +++++++++++-----
>  drivers/vhost/vdpa.c               |  27 ++++
>  include/linux/mlx5/mlx5_ifc.h      |   8 +-
>  include/linux/mlx5/mlx5_ifc_vdpa.h |   7 +-
>  include/linux/vdpa.h               |  11 ++
>  include/uapi/linux/vhost.h         |   8 ++
>  include/uapi/linux/vhost_types.h   |   5 +
>  10 files changed, 272 insertions(+), 130 deletions(-)
> 
> -- 
> 2.41.0

Re: [PATCH vhost v4 00/16] vdpa: Add support for vq descriptor mappings

[Si-Wei Liu]

For patches 05-16:

Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Tested-by: Si-Wei Liu <si-wei.liu@oracle.com>

Thanks for the fixes!

On 10/18/2023 10:14 AM, Dragos Tatulea wrote:
> This patch series adds support for vq descriptor table mappings which
> are used to improve vdpa live migration downtime. The improvement comes
> from using smaller mappings which take less time to create and destroy
> in hw.
>
> The first part adds the vdpa core changes from Si-Wei [0].
>
> The second part adds support in mlx5_vdpa:
> - Refactor the mr code to be able to cleanly add descriptor mappings.
> - Add hardware descriptor mr support.
> - Properly update iotlb for cvq during ASID switch.
>
> Changes in v4:
>
> - Improved the handling of empty iotlbs. See mlx5_vdpa_change_map
>    section in patch "12/16 vdpa/mlx5: Improve mr upate flow".
> - Fixed a invalid usage of desc_group_mkey hw vq field when the
>    capability is not there. See patch
>    "15/16 vdpa/mlx5: Enable hw support for vq descriptor map".
>
> Changes in v3:
>
> - dup_iotlb now checks for src == dst case and returns an error.
> - Renamed iotlb parameter in dup_iotlb to dst.
> - Removed a redundant check of the asid value.
> - Fixed a commit message.
> - mx5_ifc.h patch has been applied to mlx5-vhost tree. When applying
>    this series please pull from that tree first.
>
> Changes in v2:
>
> - The "vdpa/mlx5: Enable hw support for vq descriptor mapping" change
>    was split off into two patches to avoid merge conflicts into the tree
>    of Linus.
>
>    The first patch contains only changes for mlx5_ifc.h. This must be
>    applied into the mlx5-vdpa tree [1] first. Once this patch is applied
>    on mlx5-vdpa, the change has to be pulled fom mlx5-vdpa into the vhost
>    tree and only then the remaining patches can be applied.
>
> [0] https://lore.kernel.org/virtualization/1694248959-13369-1-git-send-email-si-wei.liu@oracle.com
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-vhost
>
> Dragos Tatulea (13):
>    vdpa/mlx5: Expose descriptor group mkey hw capability
>    vdpa/mlx5: Create helper function for dma mappings
>    vdpa/mlx5: Decouple cvq iotlb handling from hw mapping code
>    vdpa/mlx5: Take cvq iotlb lock during refresh
>    vdpa/mlx5: Collapse "dvq" mr add/delete functions
>    vdpa/mlx5: Rename mr destroy functions
>    vdpa/mlx5: Allow creation/deletion of any given mr struct
>    vdpa/mlx5: Move mr mutex out of mr struct
>    vdpa/mlx5: Improve mr update flow
>    vdpa/mlx5: Introduce mr for vq descriptor
>    vdpa/mlx5: Enable hw support for vq descriptor mapping
>    vdpa/mlx5: Make iotlb helper functions more generic
>    vdpa/mlx5: Update cvq iotlb mapping on ASID change
>
> Si-Wei Liu (3):
>    vdpa: introduce dedicated descriptor group for virtqueue
>    vhost-vdpa: introduce descriptor group backend feature
>    vhost-vdpa: uAPI to get dedicated descriptor group id
>
>   drivers/vdpa/mlx5/core/mlx5_vdpa.h |  31 +++--
>   drivers/vdpa/mlx5/core/mr.c        | 194 ++++++++++++++++-------------
>   drivers/vdpa/mlx5/core/resources.c |   6 +-
>   drivers/vdpa/mlx5/net/mlx5_vnet.c  | 105 +++++++++++-----
>   drivers/vhost/vdpa.c               |  27 ++++
>   include/linux/mlx5/mlx5_ifc.h      |   8 +-
>   include/linux/mlx5/mlx5_ifc_vdpa.h |   7 +-
>   include/linux/vdpa.h               |  11 ++
>   include/uapi/linux/vhost.h         |   8 ++
>   include/uapi/linux/vhost_types.h   |   5 +
>   10 files changed, 272 insertions(+), 130 deletions(-)
>

Re: [PATCH vhost v4 12/16] vdpa/mlx5: Improve mr update flow

[Eugenio Perez Martin]

On Wed, Oct 18, 2023 at 7:21 PM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>
> On Wed, 2023-10-18 at 20:14 +0300, Dragos Tatulea wrote:
> > The current flow for updating an mr works directly on mvdev->mr which
> > makes it cumbersome to handle multiple new mr structs.
> >
> > This patch makes the flow more straightforward by having
> > mlx5_vdpa_create_mr return a new mr which will update the old mr (if
> > any). The old mr will be deleted and unlinked from mvdev. For the case
> > when the iotlb is empty (not NULL), the old mr will be cleared.
> >
> > This change paves the way for adding mrs for different ASIDs.
> >
> > The initialized bool is no longer needed as mr is now a pointer in the
> > mlx5_vdpa_dev struct which will be NULL when not initialized.
> >
> > Acked-by: Eugenio Pérez <eperezma@redhat.com>
> > Acked-by: Jason Wang <jasowang@redhat.com>
> > Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> > ---
> >  drivers/vdpa/mlx5/core/mlx5_vdpa.h | 14 +++--
> >  drivers/vdpa/mlx5/core/mr.c        | 87 ++++++++++++++++--------------
> >  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 53 +++++++++---------
> >  3 files changed, 82 insertions(+), 72 deletions(-)
> >
> > diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > index 9c6ac42c21e1..bbe4335106bd 100644
> > --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > @@ -31,8 +31,6 @@ struct mlx5_vdpa_mr {
> >         struct list_head head;
> >         unsigned long num_directs;
> >         unsigned long num_klms;
> > -       /* state of dvq mr */
> > -       bool initialized;
> >
> >         bool user_mr;
> >  };
> > @@ -91,7 +89,7 @@ struct mlx5_vdpa_dev {
> >         u16 max_idx;
> >         u32 generation;
> >
> > -       struct mlx5_vdpa_mr mr;
> > +       struct mlx5_vdpa_mr *mr;
> >         /* serialize mr access */
> >         struct mutex mr_mtx;
> >         struct mlx5_control_vq cvq;
> > @@ -114,14 +112,14 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev
> > *mvdev);
> >  int mlx5_vdpa_create_mkey(struct mlx5_vdpa_dev *mvdev, u32 *mkey, u32 *in,
> >                           int inlen);
> >  int mlx5_vdpa_destroy_mkey(struct mlx5_vdpa_dev *mvdev, u32 mkey);
> > -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> > *iotlb,
> > -                            bool *change_map, unsigned int asid);
> > -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > -                       struct mlx5_vdpa_mr *mr,
> > -                       struct vhost_iotlb *iotlb);
> > +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > +                                        struct vhost_iotlb *iotlb);
> >  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
> >  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
> >                           struct mlx5_vdpa_mr *mr);
> > +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> > +                        struct mlx5_vdpa_mr *mr,
> > +                        unsigned int asid);
> >  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> >                                 struct vhost_iotlb *iotlb,
> >                                 unsigned int asid);
> > diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> > index abd6a6fb122f..00eff5a07152 100644
> > --- a/drivers/vdpa/mlx5/core/mr.c
> > +++ b/drivers/vdpa/mlx5/core/mr.c
> > @@ -495,30 +495,51 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev,
> > struct mlx5_vdpa_mr *mr
> >
> >  static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct
> > mlx5_vdpa_mr *mr)
> >  {
> > -       if (!mr->initialized)
> > -               return;
> > -
> >         if (mr->user_mr)
> >                 destroy_user_mr(mvdev, mr);
> >         else
> >                 destroy_dma_mr(mvdev, mr);
> > -
> > -       mr->initialized = false;
> >  }
> >
> >  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
> >                           struct mlx5_vdpa_mr *mr)
> >  {
> > +       if (!mr)
> > +               return;
> > +
> >         mutex_lock(&mvdev->mr_mtx);
> >
> >         _mlx5_vdpa_destroy_mr(mvdev, mr);
> >
> > +       if (mvdev->mr == mr)
> > +               mvdev->mr = NULL;
> > +
> > +       mutex_unlock(&mvdev->mr_mtx);
> > +
> > +       kfree(mr);
> > +}
> > +
> > +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> > +                        struct mlx5_vdpa_mr *new_mr,
> > +                        unsigned int asid)
> > +{
> > +       struct mlx5_vdpa_mr *old_mr = mvdev->mr;
> > +
> > +       mutex_lock(&mvdev->mr_mtx);
> > +
> > +       mvdev->mr = new_mr;
> > +       if (old_mr) {
> > +               _mlx5_vdpa_destroy_mr(mvdev, old_mr);
> > +               kfree(old_mr);
> > +       }
> > +
> >         mutex_unlock(&mvdev->mr_mtx);
> > +
> >  }
> >
> >  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
> >  {
> > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > +       mlx5_vdpa_destroy_mr(mvdev, mvdev->mr);
> >         prune_iotlb(mvdev);
> >  }
> >
> > @@ -528,52 +549,36 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev
> > *mvdev,
> >  {
> >         int err;
> >
> > -       if (mr->initialized)
> > -               return 0;
> > -
> >         if (iotlb)
> >                 err = create_user_mr(mvdev, mr, iotlb);
> >         else
> >                 err = create_dma_mr(mvdev, mr);
> >
> > -       if (err)
> > -               return err;
> > -
> > -       mr->initialized = true;
> > -
> > -       return 0;
> > +       return err;
> >  }
> >
> > -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > -                       struct mlx5_vdpa_mr *mr,
> > -                       struct vhost_iotlb *iotlb)
> > +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > +                                        struct vhost_iotlb *iotlb)
> >  {
> > +       struct mlx5_vdpa_mr *mr;
> >         int err;
> >
> > +       mr = kzalloc(sizeof(*mr), GFP_KERNEL);
> > +       if (!mr)
> > +               return ERR_PTR(-ENOMEM);
> > +
> >         mutex_lock(&mvdev->mr_mtx);
> >         err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> >         mutex_unlock(&mvdev->mr_mtx);
> >
> > -       return err;
> > -}
> > -
> > -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> > *iotlb,
> > -                            bool *change_map, unsigned int asid)
> > -{
> > -       struct mlx5_vdpa_mr *mr = &mvdev->mr;
> > -       int err = 0;
> > +       if (err)
> > +               goto out_err;
> >
> > -       *change_map = false;
> > -       mutex_lock(&mvdev->mr_mtx);
> > -       if (mr->initialized) {
> > -               mlx5_vdpa_info(mvdev, "memory map update\n");
> > -               *change_map = true;
> > -       }
> > -       if (!*change_map)
> > -               err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> > -       mutex_unlock(&mvdev->mr_mtx);
> > +       return mr;
> >
> > -       return err;
> > +out_err:
> > +       kfree(mr);
> > +       return ERR_PTR(err);
> >  }
> >
> >  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> > @@ -597,11 +602,13 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev
> > *mvdev,
> >
> >  int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
> >  {
> > -       int err;
> > +       struct mlx5_vdpa_mr *mr;
> >
> > -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, NULL);
> > -       if (err)
> > -               return err;
> > +       mr = mlx5_vdpa_create_mr(mvdev, NULL);
> > +       if (IS_ERR(mr))
> > +               return PTR_ERR(mr);
> > +
> > +       mlx5_vdpa_update_mr(mvdev, mr, 0);
> >
> >         return mlx5_vdpa_update_cvq_iotlb(mvdev, NULL, 0);
> >  }
> > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > index 256fdd80c321..7b878995b6aa 100644
> > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > @@ -873,7 +873,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev,
> > struct mlx5_vdpa_virtque
> >         MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
> >         MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
> >         MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
> > -       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr.mkey);
> > +       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr->mkey);
> >         MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
> >         MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
> >         MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
> > @@ -2633,7 +2633,7 @@ static void restore_channels_info(struct mlx5_vdpa_net
> > *ndev)
> >  }
> >
> >  static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
> > -                               struct vhost_iotlb *iotlb, unsigned int asid)
> > +                               struct mlx5_vdpa_mr *new_mr, unsigned int
> > asid)
> >  {
> >         struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> >         int err;
> > @@ -2641,27 +2641,18 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev
> > *mvdev,
> >         suspend_vqs(ndev);
> >         err = save_channels_info(ndev);
> >         if (err)
> > -               goto err_mr;
> > +               return err;
> >
> >         teardown_driver(ndev);
> > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, iotlb);
> > -       if (err)
> > -               goto err_mr;
> > +
> > +       mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> >
> >         if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK) || mvdev->suspended)
> > -               goto err_mr;
> > +               return 0;
> >
> >         restore_channels_info(ndev);
> >         err = setup_driver(mvdev);
> > -       if (err)
> > -               goto err_setup;
> > -
> > -       return 0;
> >
> > -err_setup:
> > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > -err_mr:
> >         return err;
> >  }
> >
> > @@ -2875,26 +2866,40 @@ static u32 mlx5_vdpa_get_generation(struct vdpa_device
> > *vdev)
> >  static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> > *iotlb,
> >                         unsigned int asid)
> >  {
> > -       bool change_map;
> > +       struct mlx5_vdpa_mr *new_mr;
> >         int err;
> >
> >         if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
> >                 goto end;
> >
> > -       err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map, asid);
> > -       if (err) {
> > -               mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
> > -               return err;
> > +       if (vhost_iotlb_itree_first(iotlb, 0, U64_MAX)) {
> > +               new_mr = mlx5_vdpa_create_mr(mvdev, iotlb);
> > +               if (IS_ERR(new_mr)) {
> > +                       err = PTR_ERR(new_mr);
> > +                       mlx5_vdpa_warn(mvdev, "create map failed(%d)\n", err);
> > +                       return err;
> > +               }
> > +       } else {
> > +               /* Empty iotlbs don't have an mr but will clear the previous
> > mr. */
> > +               new_mr = NULL;
> >         }
> Hi Jason and/or Eugenio, could you have a quick look at this part of the patch
> that changed please?
>
> Thanks,
> Dragos
> >
> > -       if (change_map) {
> > -               err = mlx5_vdpa_change_map(mvdev, iotlb, asid);
> > -               if (err)
> > -                       return err;
> > +       if (!mvdev->mr) {
> > +               mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> > +       } else {
> > +               err = mlx5_vdpa_change_map(mvdev, new_mr, asid);
> > +               if (err) {
> > +                       mlx5_vdpa_warn(mvdev, "change map failed(%d)\n", err);
> > +                       goto out_err;
> > +               }
> >         }
> >
> >  end:
> >         return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
> > +
> > +out_err:
> > +       mlx5_vdpa_destroy_mr(mvdev, new_mr);

Is it possible to reach this mlx5_vdpa_destroy_mr call with new_mr ==
NULL? Like:
* iotlb does not have any entries
* mdev already has a mr
* mlx5_vdpa_change_map fails

If I'm not wrong, mlx5_vdpa_destroy_mr may dereference new_mr through
_mlx5_vdpa_destroy_mr -> vhost_iotlb_free(mr->iotlb).

Am I missing something?

Thanks!




> > +       return err;
> >  }
> >
> >  static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
>

Re: [PATCH vhost v4 12/16] vdpa/mlx5: Improve mr update flow

[Dragos Tatulea]

On Fri, 2023-10-20 at 18:01 +0200, Eugenio Perez Martin wrote:
> On Wed, Oct 18, 2023 at 7:21 PM Dragos Tatulea <dtatulea@nvidia.com> wrote:
> > 
> > On Wed, 2023-10-18 at 20:14 +0300, Dragos Tatulea wrote:
> > > The current flow for updating an mr works directly on mvdev->mr which
> > > makes it cumbersome to handle multiple new mr structs.
> > > 
> > > This patch makes the flow more straightforward by having
> > > mlx5_vdpa_create_mr return a new mr which will update the old mr (if
> > > any). The old mr will be deleted and unlinked from mvdev. For the case
> > > when the iotlb is empty (not NULL), the old mr will be cleared.
> > > 
> > > This change paves the way for adding mrs for different ASIDs.
> > > 
> > > The initialized bool is no longer needed as mr is now a pointer in the
> > > mlx5_vdpa_dev struct which will be NULL when not initialized.
> > > 
> > > Acked-by: Eugenio Pérez <eperezma@redhat.com>
> > > Acked-by: Jason Wang <jasowang@redhat.com>
> > > Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> > > ---
> > >  drivers/vdpa/mlx5/core/mlx5_vdpa.h | 14 +++--
> > >  drivers/vdpa/mlx5/core/mr.c        | 87 ++++++++++++++++--------------
> > >  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 53 +++++++++---------
> > >  3 files changed, 82 insertions(+), 72 deletions(-)
> > > 
> > > diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > index 9c6ac42c21e1..bbe4335106bd 100644
> > > --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > @@ -31,8 +31,6 @@ struct mlx5_vdpa_mr {
> > >         struct list_head head;
> > >         unsigned long num_directs;
> > >         unsigned long num_klms;
> > > -       /* state of dvq mr */
> > > -       bool initialized;
> > > 
> > >         bool user_mr;
> > >  };
> > > @@ -91,7 +89,7 @@ struct mlx5_vdpa_dev {
> > >         u16 max_idx;
> > >         u32 generation;
> > > 
> > > -       struct mlx5_vdpa_mr mr;
> > > +       struct mlx5_vdpa_mr *mr;
> > >         /* serialize mr access */
> > >         struct mutex mr_mtx;
> > >         struct mlx5_control_vq cvq;
> > > @@ -114,14 +112,14 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev
> > > *mvdev);
> > >  int mlx5_vdpa_create_mkey(struct mlx5_vdpa_dev *mvdev, u32 *mkey, u32
> > > *in,
> > >                           int inlen);
> > >  int mlx5_vdpa_destroy_mkey(struct mlx5_vdpa_dev *mvdev, u32 mkey);
> > > -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct
> > > vhost_iotlb
> > > *iotlb,
> > > -                            bool *change_map, unsigned int asid);
> > > -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > -                       struct mlx5_vdpa_mr *mr,
> > > -                       struct vhost_iotlb *iotlb);
> > > +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > +                                        struct vhost_iotlb *iotlb);
> > >  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
> > >  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
> > >                           struct mlx5_vdpa_mr *mr);
> > > +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> > > +                        struct mlx5_vdpa_mr *mr,
> > > +                        unsigned int asid);
> > >  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> > >                                 struct vhost_iotlb *iotlb,
> > >                                 unsigned int asid);
> > > diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> > > index abd6a6fb122f..00eff5a07152 100644
> > > --- a/drivers/vdpa/mlx5/core/mr.c
> > > +++ b/drivers/vdpa/mlx5/core/mr.c
> > > @@ -495,30 +495,51 @@ static void destroy_user_mr(struct mlx5_vdpa_dev
> > > *mvdev,
> > > struct mlx5_vdpa_mr *mr
> > > 
> > >  static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct
> > > mlx5_vdpa_mr *mr)
> > >  {
> > > -       if (!mr->initialized)
> > > -               return;
> > > -
> > >         if (mr->user_mr)
> > >                 destroy_user_mr(mvdev, mr);
> > >         else
> > >                 destroy_dma_mr(mvdev, mr);
> > > -
> > > -       mr->initialized = false;
> > >  }
> > > 
> > >  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
> > >                           struct mlx5_vdpa_mr *mr)
> > >  {
> > > +       if (!mr)
> > > +               return;
> > > +
> > >         mutex_lock(&mvdev->mr_mtx);
> > > 
> > >         _mlx5_vdpa_destroy_mr(mvdev, mr);
> > > 
> > > +       if (mvdev->mr == mr)
> > > +               mvdev->mr = NULL;
> > > +
> > > +       mutex_unlock(&mvdev->mr_mtx);
> > > +
> > > +       kfree(mr);
> > > +}
> > > +
> > > +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> > > +                        struct mlx5_vdpa_mr *new_mr,
> > > +                        unsigned int asid)
> > > +{
> > > +       struct mlx5_vdpa_mr *old_mr = mvdev->mr;
> > > +
> > > +       mutex_lock(&mvdev->mr_mtx);
> > > +
> > > +       mvdev->mr = new_mr;
> > > +       if (old_mr) {
> > > +               _mlx5_vdpa_destroy_mr(mvdev, old_mr);
> > > +               kfree(old_mr);
> > > +       }
> > > +
> > >         mutex_unlock(&mvdev->mr_mtx);
> > > +
> > >  }
> > > 
> > >  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
> > >  {
> > > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > > +       mlx5_vdpa_destroy_mr(mvdev, mvdev->mr);
> > >         prune_iotlb(mvdev);
> > >  }
> > > 
> > > @@ -528,52 +549,36 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev
> > > *mvdev,
> > >  {
> > >         int err;
> > > 
> > > -       if (mr->initialized)
> > > -               return 0;
> > > -
> > >         if (iotlb)
> > >                 err = create_user_mr(mvdev, mr, iotlb);
> > >         else
> > >                 err = create_dma_mr(mvdev, mr);
> > > 
> > > -       if (err)
> > > -               return err;
> > > -
> > > -       mr->initialized = true;
> > > -
> > > -       return 0;
> > > +       return err;
> > >  }
> > > 
> > > -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > -                       struct mlx5_vdpa_mr *mr,
> > > -                       struct vhost_iotlb *iotlb)
> > > +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > +                                        struct vhost_iotlb *iotlb)
> > >  {
> > > +       struct mlx5_vdpa_mr *mr;
> > >         int err;
> > > 
> > > +       mr = kzalloc(sizeof(*mr), GFP_KERNEL);
> > > +       if (!mr)
> > > +               return ERR_PTR(-ENOMEM);
> > > +
> > >         mutex_lock(&mvdev->mr_mtx);
> > >         err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> > >         mutex_unlock(&mvdev->mr_mtx);
> > > 
> > > -       return err;
> > > -}
> > > -
> > > -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct
> > > vhost_iotlb
> > > *iotlb,
> > > -                            bool *change_map, unsigned int asid)
> > > -{
> > > -       struct mlx5_vdpa_mr *mr = &mvdev->mr;
> > > -       int err = 0;
> > > +       if (err)
> > > +               goto out_err;
> > > 
> > > -       *change_map = false;
> > > -       mutex_lock(&mvdev->mr_mtx);
> > > -       if (mr->initialized) {
> > > -               mlx5_vdpa_info(mvdev, "memory map update\n");
> > > -               *change_map = true;
> > > -       }
> > > -       if (!*change_map)
> > > -               err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> > > -       mutex_unlock(&mvdev->mr_mtx);
> > > +       return mr;
> > > 
> > > -       return err;
> > > +out_err:
> > > +       kfree(mr);
> > > +       return ERR_PTR(err);
> > >  }
> > > 
> > >  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> > > @@ -597,11 +602,13 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev
> > > *mvdev,
> > > 
> > >  int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
> > >  {
> > > -       int err;
> > > +       struct mlx5_vdpa_mr *mr;
> > > 
> > > -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, NULL);
> > > -       if (err)
> > > -               return err;
> > > +       mr = mlx5_vdpa_create_mr(mvdev, NULL);
> > > +       if (IS_ERR(mr))
> > > +               return PTR_ERR(mr);
> > > +
> > > +       mlx5_vdpa_update_mr(mvdev, mr, 0);
> > > 
> > >         return mlx5_vdpa_update_cvq_iotlb(mvdev, NULL, 0);
> > >  }
> > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > index 256fdd80c321..7b878995b6aa 100644
> > > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > @@ -873,7 +873,7 @@ static int create_virtqueue(struct mlx5_vdpa_net
> > > *ndev,
> > > struct mlx5_vdpa_virtque
> > >         MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
> > >         MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
> > >         MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
> > > -       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr.mkey);
> > > +       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr->mkey);
> > >         MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
> > >         MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
> > >         MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
> > > @@ -2633,7 +2633,7 @@ static void restore_channels_info(struct
> > > mlx5_vdpa_net
> > > *ndev)
> > >  }
> > > 
> > >  static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
> > > -                               struct vhost_iotlb *iotlb, unsigned int
> > > asid)
> > > +                               struct mlx5_vdpa_mr *new_mr, unsigned int
> > > asid)
> > >  {
> > >         struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> > >         int err;
> > > @@ -2641,27 +2641,18 @@ static int mlx5_vdpa_change_map(struct
> > > mlx5_vdpa_dev
> > > *mvdev,
> > >         suspend_vqs(ndev);
> > >         err = save_channels_info(ndev);
> > >         if (err)
> > > -               goto err_mr;
> > > +               return err;
> > > 
> > >         teardown_driver(ndev);
> > > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > > -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, iotlb);
> > > -       if (err)
> > > -               goto err_mr;
> > > +
> > > +       mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> > > 
> > >         if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK) || mvdev-
> > > >suspended)
> > > -               goto err_mr;
> > > +               return 0;
> > > 
> > >         restore_channels_info(ndev);
> > >         err = setup_driver(mvdev);
> > > -       if (err)
> > > -               goto err_setup;
> > > -
> > > -       return 0;
> > > 
> > > -err_setup:
> > > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > > -err_mr:
> > >         return err;
> > >  }
> > > 
> > > @@ -2875,26 +2866,40 @@ static u32 mlx5_vdpa_get_generation(struct
> > > vdpa_device
> > > *vdev)
> > >  static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> > > *iotlb,
> > >                         unsigned int asid)
> > >  {
> > > -       bool change_map;
> > > +       struct mlx5_vdpa_mr *new_mr;
> > >         int err;
> > > 
> > >         if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
> > >                 goto end;
> > > 
> > > -       err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map, asid);
> > > -       if (err) {
> > > -               mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
> > > -               return err;
> > > +       if (vhost_iotlb_itree_first(iotlb, 0, U64_MAX)) {
> > > +               new_mr = mlx5_vdpa_create_mr(mvdev, iotlb);
> > > +               if (IS_ERR(new_mr)) {
> > > +                       err = PTR_ERR(new_mr);
> > > +                       mlx5_vdpa_warn(mvdev, "create map failed(%d)\n",
> > > err);
> > > +                       return err;
> > > +               }
> > > +       } else {
> > > +               /* Empty iotlbs don't have an mr but will clear the
> > > previous
> > > mr. */
> > > +               new_mr = NULL;
> > >         }
> > Hi Jason and/or Eugenio, could you have a quick look at this part of the
> > patch
> > that changed please?
> > 
> > Thanks,
> > Dragos
> > > 
> > > -       if (change_map) {
> > > -               err = mlx5_vdpa_change_map(mvdev, iotlb, asid);
> > > -               if (err)
> > > -                       return err;
> > > +       if (!mvdev->mr) {
> > > +               mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> > > +       } else {
> > > +               err = mlx5_vdpa_change_map(mvdev, new_mr, asid);
> > > +               if (err) {
> > > +                       mlx5_vdpa_warn(mvdev, "change map failed(%d)\n",
> > > err);
> > > +                       goto out_err;
> > > +               }
> > >         }
> > > 
> > >  end:
> > >         return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
> > > +
> > > +out_err:
> > > +       mlx5_vdpa_destroy_mr(mvdev, new_mr);
> 
> Is it possible to reach this mlx5_vdpa_destroy_mr call with new_mr ==
> NULL? Like:
> * iotlb does not have any entries
> * mdev already has a mr
> * mlx5_vdpa_change_map fails
> 
It could happen.

> If I'm not wrong, mlx5_vdpa_destroy_mr may dereference new_mr through
> _mlx5_vdpa_destroy_mr -> vhost_iotlb_free(mr->iotlb).
> 
mlx5_vdpa_destroy_mr checks for mr being NULL first.

The other place where _mlx5_vdpa_destroy_mr gets called is from
mlx5_vdpa_update_mr on the old mr IF it exists (it is not NULL).

This looks safe to me.

Thanks,
Dragos

> Am I missing something?
> 
> Thanks!
> 
> 
> 
> 
> > > +       return err;
> > >  }
> > > 
> > >  static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
> > 
> 

Re: [PATCH vhost v4 00/16] vdpa: Add support for vq descriptor mappings

[Lei Yang]

QE tested this series v4 with regression testing on real nic, there
are no new issues.

Tested-by: Lei Yang <leiyang@redhat.com>


On Fri, Oct 20, 2023 at 7:50 AM Si-Wei Liu <si-wei.liu@oracle.com> wrote:
>
> For patches 05-16:
>
> Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
> Tested-by: Si-Wei Liu <si-wei.liu@oracle.com>
>
> Thanks for the fixes!
>
> On 10/18/2023 10:14 AM, Dragos Tatulea wrote:
> > This patch series adds support for vq descriptor table mappings which
> > are used to improve vdpa live migration downtime. The improvement comes
> > from using smaller mappings which take less time to create and destroy
> > in hw.
> >
> > The first part adds the vdpa core changes from Si-Wei [0].
> >
> > The second part adds support in mlx5_vdpa:
> > - Refactor the mr code to be able to cleanly add descriptor mappings.
> > - Add hardware descriptor mr support.
> > - Properly update iotlb for cvq during ASID switch.
> >
> > Changes in v4:
> >
> > - Improved the handling of empty iotlbs. See mlx5_vdpa_change_map
> >    section in patch "12/16 vdpa/mlx5: Improve mr upate flow".
> > - Fixed a invalid usage of desc_group_mkey hw vq field when the
> >    capability is not there. See patch
> >    "15/16 vdpa/mlx5: Enable hw support for vq descriptor map".
> >
> > Changes in v3:
> >
> > - dup_iotlb now checks for src == dst case and returns an error.
> > - Renamed iotlb parameter in dup_iotlb to dst.
> > - Removed a redundant check of the asid value.
> > - Fixed a commit message.
> > - mx5_ifc.h patch has been applied to mlx5-vhost tree. When applying
> >    this series please pull from that tree first.
> >
> > Changes in v2:
> >
> > - The "vdpa/mlx5: Enable hw support for vq descriptor mapping" change
> >    was split off into two patches to avoid merge conflicts into the tree
> >    of Linus.
> >
> >    The first patch contains only changes for mlx5_ifc.h. This must be
> >    applied into the mlx5-vdpa tree [1] first. Once this patch is applied
> >    on mlx5-vdpa, the change has to be pulled fom mlx5-vdpa into the vhost
> >    tree and only then the remaining patches can be applied.
> >
> > [0] https://lore.kernel.org/virtualization/1694248959-13369-1-git-send-email-si-wei.liu@oracle.com
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-vhost
> >
> > Dragos Tatulea (13):
> >    vdpa/mlx5: Expose descriptor group mkey hw capability
> >    vdpa/mlx5: Create helper function for dma mappings
> >    vdpa/mlx5: Decouple cvq iotlb handling from hw mapping code
> >    vdpa/mlx5: Take cvq iotlb lock during refresh
> >    vdpa/mlx5: Collapse "dvq" mr add/delete functions
> >    vdpa/mlx5: Rename mr destroy functions
> >    vdpa/mlx5: Allow creation/deletion of any given mr struct
> >    vdpa/mlx5: Move mr mutex out of mr struct
> >    vdpa/mlx5: Improve mr update flow
> >    vdpa/mlx5: Introduce mr for vq descriptor
> >    vdpa/mlx5: Enable hw support for vq descriptor mapping
> >    vdpa/mlx5: Make iotlb helper functions more generic
> >    vdpa/mlx5: Update cvq iotlb mapping on ASID change
> >
> > Si-Wei Liu (3):
> >    vdpa: introduce dedicated descriptor group for virtqueue
> >    vhost-vdpa: introduce descriptor group backend feature
> >    vhost-vdpa: uAPI to get dedicated descriptor group id
> >
> >   drivers/vdpa/mlx5/core/mlx5_vdpa.h |  31 +++--
> >   drivers/vdpa/mlx5/core/mr.c        | 194 ++++++++++++++++-------------
> >   drivers/vdpa/mlx5/core/resources.c |   6 +-
> >   drivers/vdpa/mlx5/net/mlx5_vnet.c  | 105 +++++++++++-----
> >   drivers/vhost/vdpa.c               |  27 ++++
> >   include/linux/mlx5/mlx5_ifc.h      |   8 +-
> >   include/linux/mlx5/mlx5_ifc_vdpa.h |   7 +-
> >   include/linux/vdpa.h               |  11 ++
> >   include/uapi/linux/vhost.h         |   8 ++
> >   include/uapi/linux/vhost_types.h   |   5 +
> >   10 files changed, 272 insertions(+), 130 deletions(-)
> >
>

Re: [PATCH vhost v4 12/16] vdpa/mlx5: Improve mr update flow

[Eugenio Perez Martin]

On Mon, Oct 23, 2023 at 10:07 AM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>
> On Fri, 2023-10-20 at 18:01 +0200, Eugenio Perez Martin wrote:
> > On Wed, Oct 18, 2023 at 7:21 PM Dragos Tatulea <dtatulea@nvidia.com> wrote:
> > >
> > > On Wed, 2023-10-18 at 20:14 +0300, Dragos Tatulea wrote:
> > > > The current flow for updating an mr works directly on mvdev->mr which
> > > > makes it cumbersome to handle multiple new mr structs.
> > > >
> > > > This patch makes the flow more straightforward by having
> > > > mlx5_vdpa_create_mr return a new mr which will update the old mr (if
> > > > any). The old mr will be deleted and unlinked from mvdev. For the case
> > > > when the iotlb is empty (not NULL), the old mr will be cleared.
> > > >
> > > > This change paves the way for adding mrs for different ASIDs.
> > > >
> > > > The initialized bool is no longer needed as mr is now a pointer in the
> > > > mlx5_vdpa_dev struct which will be NULL when not initialized.
> > > >
> > > > Acked-by: Eugenio Pérez <eperezma@redhat.com>
> > > > Acked-by: Jason Wang <jasowang@redhat.com>
> > > > Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> > > > ---
> > > >  drivers/vdpa/mlx5/core/mlx5_vdpa.h | 14 +++--
> > > >  drivers/vdpa/mlx5/core/mr.c        | 87 ++++++++++++++++--------------
> > > >  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 53 +++++++++---------
> > > >  3 files changed, 82 insertions(+), 72 deletions(-)
> > > >
> > > > diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > > b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > > index 9c6ac42c21e1..bbe4335106bd 100644
> > > > --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > > +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> > > > @@ -31,8 +31,6 @@ struct mlx5_vdpa_mr {
> > > >         struct list_head head;
> > > >         unsigned long num_directs;
> > > >         unsigned long num_klms;
> > > > -       /* state of dvq mr */
> > > > -       bool initialized;
> > > >
> > > >         bool user_mr;
> > > >  };
> > > > @@ -91,7 +89,7 @@ struct mlx5_vdpa_dev {
> > > >         u16 max_idx;
> > > >         u32 generation;
> > > >
> > > > -       struct mlx5_vdpa_mr mr;
> > > > +       struct mlx5_vdpa_mr *mr;
> > > >         /* serialize mr access */
> > > >         struct mutex mr_mtx;
> > > >         struct mlx5_control_vq cvq;
> > > > @@ -114,14 +112,14 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev
> > > > *mvdev);
> > > >  int mlx5_vdpa_create_mkey(struct mlx5_vdpa_dev *mvdev, u32 *mkey, u32
> > > > *in,
> > > >                           int inlen);
> > > >  int mlx5_vdpa_destroy_mkey(struct mlx5_vdpa_dev *mvdev, u32 mkey);
> > > > -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct
> > > > vhost_iotlb
> > > > *iotlb,
> > > > -                            bool *change_map, unsigned int asid);
> > > > -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > > -                       struct mlx5_vdpa_mr *mr,
> > > > -                       struct vhost_iotlb *iotlb);
> > > > +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > > +                                        struct vhost_iotlb *iotlb);
> > > >  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev);
> > > >  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
> > > >                           struct mlx5_vdpa_mr *mr);
> > > > +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> > > > +                        struct mlx5_vdpa_mr *mr,
> > > > +                        unsigned int asid);
> > > >  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> > > >                                 struct vhost_iotlb *iotlb,
> > > >                                 unsigned int asid);
> > > > diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> > > > index abd6a6fb122f..00eff5a07152 100644
> > > > --- a/drivers/vdpa/mlx5/core/mr.c
> > > > +++ b/drivers/vdpa/mlx5/core/mr.c
> > > > @@ -495,30 +495,51 @@ static void destroy_user_mr(struct mlx5_vdpa_dev
> > > > *mvdev,
> > > > struct mlx5_vdpa_mr *mr
> > > >
> > > >  static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct
> > > > mlx5_vdpa_mr *mr)
> > > >  {
> > > > -       if (!mr->initialized)
> > > > -               return;
> > > > -
> > > >         if (mr->user_mr)
> > > >                 destroy_user_mr(mvdev, mr);
> > > >         else
> > > >                 destroy_dma_mr(mvdev, mr);
> > > > -
> > > > -       mr->initialized = false;
> > > >  }
> > > >
> > > >  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
> > > >                           struct mlx5_vdpa_mr *mr)
> > > >  {
> > > > +       if (!mr)
> > > > +               return;
> > > > +
> > > >         mutex_lock(&mvdev->mr_mtx);
> > > >
> > > >         _mlx5_vdpa_destroy_mr(mvdev, mr);
> > > >
> > > > +       if (mvdev->mr == mr)
> > > > +               mvdev->mr = NULL;
> > > > +
> > > > +       mutex_unlock(&mvdev->mr_mtx);
> > > > +
> > > > +       kfree(mr);
> > > > +}
> > > > +
> > > > +void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> > > > +                        struct mlx5_vdpa_mr *new_mr,
> > > > +                        unsigned int asid)
> > > > +{
> > > > +       struct mlx5_vdpa_mr *old_mr = mvdev->mr;
> > > > +
> > > > +       mutex_lock(&mvdev->mr_mtx);
> > > > +
> > > > +       mvdev->mr = new_mr;
> > > > +       if (old_mr) {
> > > > +               _mlx5_vdpa_destroy_mr(mvdev, old_mr);
> > > > +               kfree(old_mr);
> > > > +       }
> > > > +
> > > >         mutex_unlock(&mvdev->mr_mtx);
> > > > +
> > > >  }
> > > >
> > > >  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
> > > >  {
> > > > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > > > +       mlx5_vdpa_destroy_mr(mvdev, mvdev->mr);
> > > >         prune_iotlb(mvdev);
> > > >  }
> > > >
> > > > @@ -528,52 +549,36 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev
> > > > *mvdev,
> > > >  {
> > > >         int err;
> > > >
> > > > -       if (mr->initialized)
> > > > -               return 0;
> > > > -
> > > >         if (iotlb)
> > > >                 err = create_user_mr(mvdev, mr, iotlb);
> > > >         else
> > > >                 err = create_dma_mr(mvdev, mr);
> > > >
> > > > -       if (err)
> > > > -               return err;
> > > > -
> > > > -       mr->initialized = true;
> > > > -
> > > > -       return 0;
> > > > +       return err;
> > > >  }
> > > >
> > > > -int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > > -                       struct mlx5_vdpa_mr *mr,
> > > > -                       struct vhost_iotlb *iotlb)
> > > > +struct mlx5_vdpa_mr *mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> > > > +                                        struct vhost_iotlb *iotlb)
> > > >  {
> > > > +       struct mlx5_vdpa_mr *mr;
> > > >         int err;
> > > >
> > > > +       mr = kzalloc(sizeof(*mr), GFP_KERNEL);
> > > > +       if (!mr)
> > > > +               return ERR_PTR(-ENOMEM);
> > > > +
> > > >         mutex_lock(&mvdev->mr_mtx);
> > > >         err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> > > >         mutex_unlock(&mvdev->mr_mtx);
> > > >
> > > > -       return err;
> > > > -}
> > > > -
> > > > -int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct
> > > > vhost_iotlb
> > > > *iotlb,
> > > > -                            bool *change_map, unsigned int asid)
> > > > -{
> > > > -       struct mlx5_vdpa_mr *mr = &mvdev->mr;
> > > > -       int err = 0;
> > > > +       if (err)
> > > > +               goto out_err;
> > > >
> > > > -       *change_map = false;
> > > > -       mutex_lock(&mvdev->mr_mtx);
> > > > -       if (mr->initialized) {
> > > > -               mlx5_vdpa_info(mvdev, "memory map update\n");
> > > > -               *change_map = true;
> > > > -       }
> > > > -       if (!*change_map)
> > > > -               err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> > > > -       mutex_unlock(&mvdev->mr_mtx);
> > > > +       return mr;
> > > >
> > > > -       return err;
> > > > +out_err:
> > > > +       kfree(mr);
> > > > +       return ERR_PTR(err);
> > > >  }
> > > >
> > > >  int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> > > > @@ -597,11 +602,13 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev
> > > > *mvdev,
> > > >
> > > >  int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev)
> > > >  {
> > > > -       int err;
> > > > +       struct mlx5_vdpa_mr *mr;
> > > >
> > > > -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, NULL);
> > > > -       if (err)
> > > > -               return err;
> > > > +       mr = mlx5_vdpa_create_mr(mvdev, NULL);
> > > > +       if (IS_ERR(mr))
> > > > +               return PTR_ERR(mr);
> > > > +
> > > > +       mlx5_vdpa_update_mr(mvdev, mr, 0);
> > > >
> > > >         return mlx5_vdpa_update_cvq_iotlb(mvdev, NULL, 0);
> > > >  }
> > > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > > b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > > index 256fdd80c321..7b878995b6aa 100644
> > > > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > > @@ -873,7 +873,7 @@ static int create_virtqueue(struct mlx5_vdpa_net
> > > > *ndev,
> > > > struct mlx5_vdpa_virtque
> > > >         MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
> > > >         MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
> > > >         MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
> > > > -       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr.mkey);
> > > > +       MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, ndev->mvdev.mr->mkey);
> > > >         MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
> > > >         MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
> > > >         MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
> > > > @@ -2633,7 +2633,7 @@ static void restore_channels_info(struct
> > > > mlx5_vdpa_net
> > > > *ndev)
> > > >  }
> > > >
> > > >  static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
> > > > -                               struct vhost_iotlb *iotlb, unsigned int
> > > > asid)
> > > > +                               struct mlx5_vdpa_mr *new_mr, unsigned int
> > > > asid)
> > > >  {
> > > >         struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> > > >         int err;
> > > > @@ -2641,27 +2641,18 @@ static int mlx5_vdpa_change_map(struct
> > > > mlx5_vdpa_dev
> > > > *mvdev,
> > > >         suspend_vqs(ndev);
> > > >         err = save_channels_info(ndev);
> > > >         if (err)
> > > > -               goto err_mr;
> > > > +               return err;
> > > >
> > > >         teardown_driver(ndev);
> > > > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > > > -       err = mlx5_vdpa_create_mr(mvdev, &mvdev->mr, iotlb);
> > > > -       if (err)
> > > > -               goto err_mr;
> > > > +
> > > > +       mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> > > >
> > > >         if (!(mvdev->status & VIRTIO_CONFIG_S_DRIVER_OK) || mvdev-
> > > > >suspended)
> > > > -               goto err_mr;
> > > > +               return 0;
> > > >
> > > >         restore_channels_info(ndev);
> > > >         err = setup_driver(mvdev);
> > > > -       if (err)
> > > > -               goto err_setup;
> > > > -
> > > > -       return 0;
> > > >
> > > > -err_setup:
> > > > -       mlx5_vdpa_destroy_mr(mvdev, &mvdev->mr);
> > > > -err_mr:
> > > >         return err;
> > > >  }
> > > >
> > > > @@ -2875,26 +2866,40 @@ static u32 mlx5_vdpa_get_generation(struct
> > > > vdpa_device
> > > > *vdev)
> > > >  static int set_map_data(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> > > > *iotlb,
> > > >                         unsigned int asid)
> > > >  {
> > > > -       bool change_map;
> > > > +       struct mlx5_vdpa_mr *new_mr;
> > > >         int err;
> > > >
> > > >         if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
> > > >                 goto end;
> > > >
> > > > -       err = mlx5_vdpa_handle_set_map(mvdev, iotlb, &change_map, asid);
> > > > -       if (err) {
> > > > -               mlx5_vdpa_warn(mvdev, "set map failed(%d)\n", err);
> > > > -               return err;
> > > > +       if (vhost_iotlb_itree_first(iotlb, 0, U64_MAX)) {
> > > > +               new_mr = mlx5_vdpa_create_mr(mvdev, iotlb);
> > > > +               if (IS_ERR(new_mr)) {
> > > > +                       err = PTR_ERR(new_mr);
> > > > +                       mlx5_vdpa_warn(mvdev, "create map failed(%d)\n",
> > > > err);
> > > > +                       return err;
> > > > +               }
> > > > +       } else {
> > > > +               /* Empty iotlbs don't have an mr but will clear the
> > > > previous
> > > > mr. */
> > > > +               new_mr = NULL;
> > > >         }
> > > Hi Jason and/or Eugenio, could you have a quick look at this part of the
> > > patch
> > > that changed please?
> > >
> > > Thanks,
> > > Dragos
> > > >
> > > > -       if (change_map) {
> > > > -               err = mlx5_vdpa_change_map(mvdev, iotlb, asid);
> > > > -               if (err)
> > > > -                       return err;
> > > > +       if (!mvdev->mr) {
> > > > +               mlx5_vdpa_update_mr(mvdev, new_mr, asid);
> > > > +       } else {
> > > > +               err = mlx5_vdpa_change_map(mvdev, new_mr, asid);
> > > > +               if (err) {
> > > > +                       mlx5_vdpa_warn(mvdev, "change map failed(%d)\n",
> > > > err);
> > > > +                       goto out_err;
> > > > +               }
> > > >         }
> > > >
> > > >  end:
> > > >         return mlx5_vdpa_update_cvq_iotlb(mvdev, iotlb, asid);
> > > > +
> > > > +out_err:
> > > > +       mlx5_vdpa_destroy_mr(mvdev, new_mr);
> >
> > Is it possible to reach this mlx5_vdpa_destroy_mr call with new_mr ==
> > NULL? Like:
> > * iotlb does not have any entries
> > * mdev already has a mr
> > * mlx5_vdpa_change_map fails
> >
> It could happen.
>
> > If I'm not wrong, mlx5_vdpa_destroy_mr may dereference new_mr through
> > _mlx5_vdpa_destroy_mr -> vhost_iotlb_free(mr->iotlb).
> >
> mlx5_vdpa_destroy_mr checks for mr being NULL first.
>
> The other place where _mlx5_vdpa_destroy_mr gets called is from
> mlx5_vdpa_update_mr on the old mr IF it exists (it is not NULL).
>
> This looks safe to me.
>

Right, I don't know how I missed that, sorry for the noise! Already
acked in the patch message, but just in case:

Acked-by: Eugenio Pérez <eperezma@redhat.com>

Thanks!

> Thanks,
> Dragos
>
> > Am I missing something?
> >
> > Thanks!
> >
> >
> >
> >
> > > > +       return err;
> > > >  }
> > > >
> > > >  static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
> > >
> >
>