Si-Wei Liu
2023-Sep-09 13:43 UTC
[PATCH RFC v3 2/4] vdpa/mlx5: implement .reset_map driver op
Today, mlx5_vdpa gets started by preallocate 1:1 DMA mapping at
device creation time, while this 1:1 mapping will be implicitly
destroyed when the first .set_map call is invoked. Everytime
when the .reset callback is invoked, any mapping left behind will
be dropped then reset back to the initial 1:1 DMA mapping.
In order to reduce excessive memory mapping cost during live
migration, it is desirable to decouple the vhost-vdpa iotlb
abstraction from the virtio device life cycle, i.e. mappings
should be left intact across virtio device reset. Leverage the
.reset_map callback to reset memory mapping, then the device
.reset routine can run free from having to clean up memory
mappings.
Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
RFC v1 -> v2:
- fix error path when both CVQ and DVQ fall in same asid
---
drivers/vdpa/mlx5/core/mlx5_vdpa.h | 1 +
drivers/vdpa/mlx5/core/mr.c | 70 +++++++++++++++++++++++---------------
drivers/vdpa/mlx5/net/mlx5_vnet.c | 18 +++++++---
3 files changed, 56 insertions(+), 33 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..ec2c7b4e1 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;
@@ -574,18 +562,22 @@ 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);
+ if (err)
+ return err;
+ }
+ if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid) {
+ err = _mlx5_vdpa_create_cvq_mr(mvdev, iotlb);
+ if (err)
+ goto out_err;
+ }
return 0;
out_err:
- _mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
+ if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid)
+ _mlx5_vdpa_destroy_dvq_mr(mvdev);
return err;
}
@@ -601,6 +593,28 @@ 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);
+ 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 37be945..3cb5db6 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2824,7 +2824,6 @@ 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;
@@ -2835,10 +2834,6 @@ 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;
@@ -2903,6 +2898,18 @@ 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);
@@ -3162,6 +3169,7 @@ 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,
--
1.8.3.1
Jason Wang
2023-Sep-11 03:48 UTC
[PATCH RFC v3 2/4] vdpa/mlx5: implement .reset_map driver op
On Sat, Sep 9, 2023 at 9:46?PM Si-Wei Liu <si-wei.liu at oracle.com> wrote:> > Today, mlx5_vdpa gets started by preallocate 1:1 DMA mapping at > device creation time, while this 1:1 mapping will be implicitly > destroyed when the first .set_map call is invoked. Everytime > when the .reset callback is invoked, any mapping left behind will > be dropped then reset back to the initial 1:1 DMA mapping. > > In order to reduce excessive memory mapping cost during live > migration, it is desirable to decouple the vhost-vdpa iotlb > abstraction from the virtio device life cycle, i.e. mappings > should be left intact across virtio device reset. Leverage the > .reset_map callback to reset memory mapping, then the device > .reset routine can run free from having to clean up memory > mappings.It's not clear the direct relationship between the persistent mapping and reset_map. Could we do it step by step? For example, remove the mlx5_vdpa_destroy_mr() in mlx5_vdpa_reset() when PERSIST_IOTLB exists? And then we can deal with the resetting and others on top, or it needs some explanation for why reset_map() must be done first. Thanks> > Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com> > > --- > RFC v1 -> v2: > - fix error path when both CVQ and DVQ fall in same asid > --- > drivers/vdpa/mlx5/core/mlx5_vdpa.h | 1 + > drivers/vdpa/mlx5/core/mr.c | 70 +++++++++++++++++++++++--------------- > drivers/vdpa/mlx5/net/mlx5_vnet.c | 18 +++++++--- > 3 files changed, 56 insertions(+), 33 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..ec2c7b4e1 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; > > @@ -574,18 +562,22 @@ 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); > + if (err) > + return err; > + } > + if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid) { > + err = _mlx5_vdpa_create_cvq_mr(mvdev, iotlb); > + if (err) > + goto out_err; > + } > > return 0; > > out_err: > - _mlx5_vdpa_destroy_dvq_mr(mvdev, asid); > + if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) > + _mlx5_vdpa_destroy_dvq_mr(mvdev); > > return err; > } > @@ -601,6 +593,28 @@ 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); > + 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 37be945..3cb5db6 100644 > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > @@ -2824,7 +2824,6 @@ 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; > @@ -2835,10 +2834,6 @@ 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; > @@ -2903,6 +2898,18 @@ 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); > @@ -3162,6 +3169,7 @@ 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, > -- > 1.8.3.1 >