vhost: support ASID in IOTLB API

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@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
Message-Id: <20220330180436.24644-10-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 9202ff97ddb5f1f452947bb30c71d4dda6273fff..174c9e81df4eb9a75dfe71725a38d75d3aa7de22 100644 (file)
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -870,7 +870,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
                                 msg->perm);
 }
 
-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);
@@ -879,6 +879,9 @@ 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;
+
        mutex_lock(&dev->mutex);
 
        r = vhost_dev_check_owner(dev);

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index d02173fb290c39146634e0d08e14ea123ae174f5..d1e58f976f6ef08dab950eab6dbda0800de5415e 100644 (file)
--- 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;
@@ -1090,11 +1090,14 @@ 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, u32 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) {
@@ -1141,6 +1144,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
        struct vhost_iotlb_msg msg;
        size_t offset;
        int type, ret;
+       u32 asid = 0;
 
        ret = copy_from_iter(&type, sizeof(type), from);
        if (ret != sizeof(type)) {
@@ -1156,7 +1160,16 @@ 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;
@@ -1178,9 +1191,9 @@ 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 638bb640d6b4b5f7d0ce20b2bab5461ba8b2cfbd..9f238d6c7b580e3fd84e5415cc689796de2518c0 100644 (file)
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -161,7 +161,7 @@ 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);
 };
 
@@ -169,7 +169,7 @@ 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 76ee7016c501184a26e4951a2e2be80c5b5cc8b3..634cee485abbcfbf186917892f8af4ab32a6822d 100644 (file)
--- 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 +157,9 @@ 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