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From:   Dragos Tatulea <dtatulea@nvidia.com>
To:     "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>
CC:     Dragos Tatulea <dtatulea@nvidia.com>,
        =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>,
        Gal Pressman <gal@nvidia.com>,
        <virtualization@lists.linux-foundation.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH 1/2] vdpa/mlx5: Fix mr->initialized semantics
Date:   Wed, 2 Aug 2023 20:12:18 +0300
Message-ID: <20230802171231.11001-3-dtatulea@nvidia.com>
In-Reply-To: <20230802171231.11001-1-dtatulea@nvidia.com>
References: <20230802171231.11001-1-dtatulea@nvidia.com>
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The mr->initialized flag is shared between the control vq and data vq
part of the mr init/uninit. But if the control vq and data vq get placed
in different ASIDs, it can happen that initializing the control vq will
prevent the data vq mr from being initialized.

This patch consolidates the control and data vq init parts into their
own init functions. The mr->initialized will now be used for the data vq
only. The control vq currently doesn't need a flag.

The uninitializing part is also taken care of: mlx5_vdpa_destroy_mr got
split into data and control vq functions which are now also ASID aware.

Fixes: 8fcd20c30704 ("vdpa/mlx5: Support different address spaces for control and data")
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |  1 +
 drivers/vdpa/mlx5/core/mr.c        | 97 +++++++++++++++++++++---------
 2 files changed, 71 insertions(+), 27 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index 25fc4120b618..a0420be5059f 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -31,6 +31,7 @@ struct mlx5_vdpa_mr {
 	struct list_head head;
 	unsigned long num_directs;
 	unsigned long num_klms;
+	/* state of dvq mr */
 	bool initialized;
 
 	/* serialize mkey creation and destruction */
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 03e543229791..4ae14a248a4b 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -489,60 +489,103 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr
 	}
 }
 
-void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
+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;
 
-	mutex_lock(&mr->mkey_mtx);
+	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
+		return;
+
 	if (!mr->initialized)
-		goto out;
+		return;
 
-	prune_iotlb(mvdev);
 	if (mr->user_mr)
 		destroy_user_mr(mvdev, mr);
 	else
 		destroy_dma_mr(mvdev, mr);
 
 	mr->initialized = false;
-out:
+}
+
+static void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
+{
+	struct mlx5_vdpa_mr *mr = &mvdev->mr;
+
+	mutex_lock(&mr->mkey_mtx);
+
+	_mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
+	_mlx5_vdpa_destroy_cvq_mr(mvdev, asid);
+
 	mutex_unlock(&mr->mkey_mtx);
 }
 
-static 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)
+{
+	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);
+}
+
+static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
+				    struct vhost_iotlb *iotlb,
+				    unsigned int asid)
 {
 	struct mlx5_vdpa_mr *mr = &mvdev->mr;
 	int err;
 
-	if (mr->initialized)
+	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
 		return 0;
 
-	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) {
-		if (iotlb)
-			err = create_user_mr(mvdev, iotlb);
-		else
-			err = create_dma_mr(mvdev, mr);
+	if (mr->initialized)
+		return 0;
 
-		if (err)
-			return err;
-	}
+	if (iotlb)
+		err = create_user_mr(mvdev, iotlb);
+	else
+		err = create_dma_mr(mvdev, mr);
 
-	if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid) {
-		err = dup_iotlb(mvdev, iotlb);
-		if (err)
-			goto out_err;
-	}
+	if (err)
+		return err;
 
 	mr->initialized = true;
+
+	return 0;
+}
+
+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:
-	if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) {
-		if (iotlb)
-			destroy_user_mr(mvdev, mr);
-		else
-			destroy_dma_mr(mvdev, mr);
-	}
+	_mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
 
 	return err;
 }
-- 
2.41.0