vhost: add vhost_set_log_base op

Split VHOST_SET_LOG_BASE call in a seperate function callback, so that
type safety works and more arguments can be added in the next patches.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NThibaut Collet <thibaut.collet@6wind.com>

hw/virtio/vhost-backend.c

@@ -67,6 +67,11 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
     return limit;
 }
 
+static int vhost_set_log_base(struct vhost_dev *dev, uint64_t base)
+{
+    return vhost_kernel_call(dev, VHOST_SET_LOG_BASE, &base);
+}
+
 static const VhostOps kernel_ops = {
         .backend_type = VHOST_BACKEND_TYPE_KERNEL,
         .vhost_call = vhost_kernel_call,
@@ -74,6 +79,7 @@ static const VhostOps kernel_ops = {
         .vhost_backend_cleanup = vhost_kernel_cleanup,
         .vhost_backend_get_vq_index = vhost_kernel_get_vq_index,
         .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
+        .vhost_set_log_base = vhost_set_log_base,
 };
 
 int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)

hw/virtio/vhost-user.c

@@ -242,7 +242,6 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
         break;
 
     case VHOST_USER_SET_FEATURES:
-    case VHOST_USER_SET_LOG_BASE:
     case VHOST_USER_SET_PROTOCOL_FEATURES:
         msg.u64 = *((__u64 *) arg);
         msg.size = sizeof(m.u64);
@@ -367,6 +366,20 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
     return 0;
 }
 
+static int vhost_set_log_base(struct vhost_dev *dev, uint64_t base)
+{
+    VhostUserMsg msg = {
+        .request = VHOST_USER_SET_LOG_BASE,
+        .flags = VHOST_USER_VERSION,
+        .u64 = base,
+        .size = sizeof(m.u64),
+    };
+
+    vhost_user_write(dev, &msg, NULL, 0);
+
+    return 0;
+}
+
 static int vhost_user_init(struct vhost_dev *dev, void *opaque)
 {
     unsigned long long features;
@@ -453,4 +466,5 @@ const VhostOps user_ops = {
         .vhost_backend_get_vq_index = vhost_user_get_vq_index,
         .vhost_backend_set_vring_enable = vhost_user_set_vring_enable,
         .vhost_backend_memslots_limit = vhost_user_memslots_limit,
+        .vhost_set_log_base = vhost_set_log_base,
 };

hw/virtio/vhost.c

@@ -352,7 +352,7 @@ static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
 
     /* inform backend of log switching, this must be done before
        releasing the current log, to ensure no logging is lost */
-    r = dev->vhost_ops->vhost_call(dev, VHOST_SET_LOG_BASE, &log_base);
+    r = dev->vhost_ops->vhost_set_log_base(dev, log_base);
     assert(r >= 0);
     vhost_log_put(dev, true);
     dev->log = log;
@@ -1167,8 +1167,8 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
         hdev->log_size = vhost_get_log_size(hdev);
         hdev->log = vhost_log_get(hdev->log_size);
         log_base = (uintptr_t)hdev->log->log;
-        r = hdev->vhost_ops->vhost_call(hdev, VHOST_SET_LOG_BASE,
-                                        hdev->log_size ? &log_base : NULL);
+        r = hdev->vhost_ops->vhost_set_log_base(hdev,
+                                                hdev->log_size ? log_base : 0);
         if (r < 0) {
             r = -errno;
             goto fail_log;

include/hw/virtio/vhost-backend.h

@@ -28,6 +28,8 @@ typedef int (*vhost_backend_get_vq_index)(struct vhost_dev *dev, int idx);
 typedef int (*vhost_backend_set_vring_enable)(struct vhost_dev *dev, int enable);
 typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
 
+typedef int (*vhost_set_log_base_op)(struct vhost_dev *dev, uint64_t base);
+
 typedef struct VhostOps {
     VhostBackendType backend_type;
     vhost_call vhost_call;
@@ -36,6 +38,7 @@ typedef struct VhostOps {
     vhost_backend_get_vq_index vhost_backend_get_vq_index;
     vhost_backend_set_vring_enable vhost_backend_set_vring_enable;
     vhost_backend_memslots_limit vhost_backend_memslots_limit;
+    vhost_set_log_base_op vhost_set_log_base;
 } VhostOps;
 
 extern const VhostOps user_ops;