Re: [PATCH RFC 2/4] vdpa/mlx5: implement .reset_map driver op

From: Si-Wei Liu
Date: Tue Aug 15 2023 - 19:12:55 EST




On 8/15/2023 1:26 AM, Dragos Tatulea wrote:
On Mon, 2023-08-14 at 18:43 -0700, Si-Wei Liu wrote:
This patch is based on top of the "vdpa/mlx5: Fixes
for ASID handling" series [1].

[1] vdpa/mlx5: Fixes for ASID handling
https://lore.kernel.org/virtualization/20230802171231.11001-1-dtatulea@xxxxxxxxxx/

Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  1 +
 drivers/vdpa/mlx5/core/mr.c        | 72 +++++++++++++++++++++----------------
-
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 18 +++++++---
 3 files changed, 54 insertions(+), 37 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index b53420e..5c9a25a 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -123,6 +123,7 @@ 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_reset_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
 #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 5a1971fc..c8d64fc 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -489,21 +489,15 @@ 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)
+static void _mlx5_vdpa_destroy_cvq_mr(struct mlx5_vdpa_dev *mvdev)
 {
-       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)
+static void _mlx5_vdpa_destroy_dvq_mr(struct mlx5_vdpa_dev *mvdev)
 {
        struct mlx5_vdpa_mr *mr = &mvdev->mr;
-       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
-               return;
-
        if (!mr->initialized)
                return;
@@ -521,8 +515,10 @@ 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);
+       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid)
+               _mlx5_vdpa_destroy_dvq_mr(mvdev);
+       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid)
+               _mlx5_vdpa_destroy_cvq_mr(mvdev);
        mutex_unlock(&mr->mkey_mtx);
 }
@@ -534,25 +530,17 @@ void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
 }
 static int _mlx5_vdpa_create_cvq_mr(struct mlx5_vdpa_dev *mvdev,
-                                   struct vhost_iotlb *iotlb,
-                                   unsigned int asid)
+                                   struct vhost_iotlb *iotlb)
 {
-       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
-               return 0;
-
        return dup_iotlb(mvdev, iotlb);
 }
 static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
-                                   struct vhost_iotlb *iotlb,
-                                   unsigned int asid)
+                                   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;
@@ -574,20 +562,18 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev
*mvdev,
 {
        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;
+       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) {
+               err = _mlx5_vdpa_create_dvq_mr(mvdev, iotlb, asid);
+               if (err)
+                       return err;
+       }
+       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid) {
+               err = _mlx5_vdpa_create_cvq_mr(mvdev, iotlb);
+               if (err)
+                       return err;
I think you still need the goto here, when CVQ and DVQ fall in same asid and
there's a CVQ mr creation error, you are left stuck with the DVQ mr.
Yes, you are right, I will fix this in v2. Thank you for spotting this!

-Siwei


+       }
        return 0;
-
-out_err:
-       _mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
-
-       return err;
 }
 int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
*iotlb,
@@ -601,6 +587,28 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
struct vhost_iotlb *iotlb,
        return err;
 }
+int mlx5_vdpa_reset_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
+{
+       struct mlx5_vdpa_mr *mr = &mvdev->mr;
+       int err = 0;
+
+       if (asid != 0)
+               return 0;
+
+       mutex_lock(&mr->mkey_mtx);
+       if (!mr->user_mr)
+               goto out;
+       _mlx5_vdpa_destroy_dvq_mr(mvdev);
+       if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
+               err = _mlx5_vdpa_create_dvq_mr(mvdev, NULL, 0);
+               if (err)
+                       mlx5_vdpa_warn(mvdev, "create DMA MR failed\n");
+       }
+out:
+       mutex_unlock(&mr->mkey_mtx);
+       return err;
+}
+
 int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
*iotlb,
                             bool *change_map, unsigned int asid)
 {
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 61c10ba..399a690 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2816,7 +2816,6 @@ 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);
        ndev->mvdev.status = 0;
        ndev->mvdev.suspended = false;
        ndev->cur_num_vqs = 0;
@@ -2827,10 +2826,6 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
        init_group_to_asid_map(mvdev);
        ++mvdev->generation;
-       if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
-               if (mlx5_vdpa_create_mr(mvdev, NULL, 0))
-                       mlx5_vdpa_warn(mvdev, "create MR failed\n");
-       }
        up_write(&ndev->reslock);
        return 0;
@@ -2895,6 +2890,18 @@ static int mlx5_vdpa_set_map(struct vdpa_device *vdev,
unsigned int asid,
        return err;
 }
+static int mlx5_vdpa_reset_map(struct vdpa_device *vdev, unsigned int asid)
+{
+       struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+       struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
+       int err;
+
+       down_write(&ndev->reslock);
+       err = mlx5_vdpa_reset_mr(mvdev, asid);
+       up_write(&ndev->reslock);
+       return err;
+}
+
 static struct device *mlx5_get_vq_dma_dev(struct vdpa_device *vdev, u16 idx)
 {
        struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
@@ -3154,6 +3161,7 @@ static int mlx5_set_group_asid(struct vdpa_device *vdev,
u32 group,
        .set_config = mlx5_vdpa_set_config,
        .get_generation = mlx5_vdpa_get_generation,
        .set_map = mlx5_vdpa_set_map,
+       .reset_map = mlx5_vdpa_reset_map,
        .set_group_asid = mlx5_set_group_asid,
        .get_vq_dma_dev = mlx5_get_vq_dma_dev,
        .free = mlx5_vdpa_free,