On Wed, Dec 16, 2020 at 02:48:07PM +0800, Jason Wang wrote:
> This patches allows userspace to send ASID based IOTLB message to
> vhost. This idea is to use the reserved u32 field in the existing V2
> IOTLB message. Vhost device should advertise this capability via
> VHOST_BACKEND_F_IOTLB_ASID backend feature.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vhost/vdpa.c | 5 ++++-
> drivers/vhost/vhost.c | 23 ++++++++++++++++++-----
> drivers/vhost/vhost.h | 4 ++--
> include/uapi/linux/vhost_types.h | 5 ++++-
> 4 files changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 03a9b3311c6c..feb6a58df22d 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -739,7 +739,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
> return ret;
> }
>
> -static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
> +static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, u32 asid,
> struct vhost_iotlb_msg *msg)
> {
> struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
> @@ -748,6 +748,9 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
> struct vhost_iotlb *iotlb = v->iotlb;
> int r = 0;
>
> + if (asid != 0)
> + return -EINVAL;
> +
> r = vhost_dev_check_owner(dev);
> if (r)
> return r;
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index a262e12c6dc2..7477b724c29b 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -468,7 +468,7 @@ void vhost_dev_init(struct vhost_dev *dev,
> struct vhost_virtqueue **vqs, int nvqs,
> int iov_limit, int weight, int byte_weight,
> bool use_worker,
> - int (*msg_handler)(struct vhost_dev *dev,
> + int (*msg_handler)(struct vhost_dev *dev, u32 asid,
> struct vhost_iotlb_msg *msg))
> {
> struct vhost_virtqueue *vq;
> @@ -1084,11 +1084,14 @@ static bool umem_access_ok(u64 uaddr, u64 size, int access)
> return true;
> }
>
> -static int vhost_process_iotlb_msg(struct vhost_dev *dev,
> +static int vhost_process_iotlb_msg(struct vhost_dev *dev, u16 asid,
> struct vhost_iotlb_msg *msg)
> {
> int ret = 0;
>
> + if (asid != 0)
> + return -EINVAL;
> +
> mutex_lock(&dev->mutex);
> vhost_dev_lock_vqs(dev);
> switch (msg->type) {
> @@ -1135,6 +1138,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> struct vhost_iotlb_msg msg;
> size_t offset;
> int type, ret;
> + u16 asid = 0;
You assume asid occupies just 16 bits. So maybe you should reserve the
other 16 bits for future extension:
struct vhost_msg_v2 {
__u32 type;
- __u32 reserved;
+ __u16 asid;
+ __u16 reserved;
union {
Moreover, maybe this should be reflected in previous patches that use
the asid:
-static int mlx5_vdpa_set_map(struct vdpa_device *vdev, struct vhost_iotlb *iotlb)
+static int mlx5_vdpa_set_map(struct vdpa_device *vdev, u16 asid,
+ struct vhost_iotlb *iotlb)
-static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
+static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, u16 asid,
struct vhost_iotlb_msg *msg)
etc.
>
> ret = copy_from_iter(&type, sizeof(type), from);
> if (ret != sizeof(type)) {
> @@ -1150,7 +1154,16 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
> break;
> case VHOST_IOTLB_MSG_V2:
> - offset = sizeof(__u32);
> + if (vhost_backend_has_feature(dev->vqs[0],
> + VHOST_BACKEND_F_IOTLB_ASID)) {
> + ret = copy_from_iter(&asid, sizeof(asid), from);
> + if (ret != sizeof(asid)) {
> + ret = -EINVAL;
> + goto done;
> + }
> + offset = sizeof(__u16);
> + } else
> + offset = sizeof(__u32);
> break;
> default:
> ret = -EINVAL;
> @@ -1165,9 +1178,9 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> }
>
> if (dev->msg_handler)
> - ret = dev->msg_handler(dev, &msg);
> + ret = dev->msg_handler(dev, asid, &msg);
> else
> - ret = vhost_process_iotlb_msg(dev, &msg);
> + ret = vhost_process_iotlb_msg(dev, asid, &msg);
> if (ret) {
> ret = -EFAULT;
> goto done;
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index b063324c7669..19753a90875c 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -162,7 +162,7 @@ struct vhost_dev {
> int byte_weight;
> u64 kcov_handle;
> bool use_worker;
> - int (*msg_handler)(struct vhost_dev *dev,
> + int (*msg_handler)(struct vhost_dev *dev, u32 asid,
> struct vhost_iotlb_msg *msg);
> };
>
> @@ -170,7 +170,7 @@ bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
> void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
> int nvqs, int iov_limit, int weight, int byte_weight,
> bool use_worker,
> - int (*msg_handler)(struct vhost_dev *dev,
> + int (*msg_handler)(struct vhost_dev *dev, u32 asid,
> struct vhost_iotlb_msg *msg));
> long vhost_dev_set_owner(struct vhost_dev *dev);
> bool vhost_dev_has_owner(struct vhost_dev *dev);
> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
> index 76ee7016c501..222fc66ce2ac 100644
> --- a/include/uapi/linux/vhost_types.h
> +++ b/include/uapi/linux/vhost_types.h
> @@ -87,7 +87,7 @@ struct vhost_msg {
>
> struct vhost_msg_v2 {
> __u32 type;
> - __u32 reserved;
> + __u32 asid;
> union {
> struct vhost_iotlb_msg iotlb;
> __u8 padding[64];
> @@ -157,5 +157,8 @@ struct vhost_vdpa_iova_range {
> #define VHOST_BACKEND_F_IOTLB_MSG_V2 0x1
> /* IOTLB can accept batching hints */
> #define VHOST_BACKEND_F_IOTLB_BATCH 0x2
> +/* IOTLB can accept address space identifier through V2 type of IOTLB
> + message */
> +#define VHOST_BACKEND_F_IOTLB_ASID 0x3
>
> #endif
> --
> 2.25.1
>
