[RFC PATCH for 8.1 2/6] vdpa: add vhost_vdpa_reset_status_fd

["Eugenio Pérez" <eperezma@redhat.com>]

This allows to reset a vhost-vdpa device from external subsystems like
vhost-net.  It is used in subsequent patches to negotiate features and
probe for CVQ ASID isolation.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h |  1 +
 hw/virtio/vhost-vdpa.c         | 58 +++++++++++++++++++++++-----------
 2 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index c278a2a8de..28de7da91e 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -54,6 +54,7 @@ typedef struct vhost_vdpa {
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
 
+void vhost_vdpa_reset_status_fd(int fd);
 int vhost_vdpa_get_iova_range(int fd, struct vhost_vdpa_iova_range *iova_range);
 
 int vhost_vdpa_dma_map(struct vhost_vdpa *v, uint32_t asid, hwaddr iova,
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index bbabea18f3..7a2053b8d9 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -335,38 +335,45 @@ static const MemoryListener vhost_vdpa_memory_listener = {
     .region_del = vhost_vdpa_listener_region_del,
 };
 
-static int vhost_vdpa_call(struct vhost_dev *dev, unsigned long int request,
-                             void *arg)
+static int vhost_vdpa_dev_fd(const struct vhost_dev *dev)
 {
     struct vhost_vdpa *v = dev->opaque;
-    int fd = v->device_fd;
-    int ret;
 
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
+    return v->device_fd;
+}
+
+static int vhost_vdpa_call_fd(int fd, unsigned long int request, void *arg)
+{
+    int ret = ioctl(fd, request, arg);
 
-    ret = ioctl(fd, request, arg);
     return ret < 0 ? -errno : ret;
 }
 
-static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
+static int vhost_vdpa_call(struct vhost_dev *dev, unsigned long int request,
+                           void *arg)
+{
+    return vhost_vdpa_call_fd(vhost_vdpa_dev_fd(dev), request, arg);
+}
+
+static int vhost_vdpa_add_status_fd(int fd, uint8_t status)
 {
     uint8_t s;
     int ret;
 
-    trace_vhost_vdpa_add_status(dev, status);
-    ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &s);
+    ret = vhost_vdpa_call_fd(fd, VHOST_VDPA_GET_STATUS, &s);
     if (ret < 0) {
         return ret;
     }
 
     s |= status;
 
-    ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
+    ret = vhost_vdpa_call_fd(fd, VHOST_VDPA_SET_STATUS, &s);
     if (ret < 0) {
         return ret;
     }
 
-    ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &s);
+    ret = vhost_vdpa_call_fd(fd, VHOST_VDPA_GET_STATUS, &s);
     if (ret < 0) {
         return ret;
     }
@@ -378,6 +385,12 @@ static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
     return 0;
 }
 
+static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
+{
+    trace_vhost_vdpa_add_status(dev, status);
+    return vhost_vdpa_add_status_fd(vhost_vdpa_dev_fd(dev), status);
+}
+
 int vhost_vdpa_get_iova_range(int fd, struct vhost_vdpa_iova_range *iova_range)
 {
     int ret = ioctl(fd, VHOST_VDPA_GET_IOVA_RANGE, iova_range);
@@ -709,16 +722,20 @@ static int vhost_vdpa_get_device_id(struct vhost_dev *dev,
     return ret;
 }
 
+static int vhost_vdpa_reset_device_fd(int fd)
+{
+    uint8_t status = 0;
+
+    return vhost_vdpa_call_fd(fd, VHOST_VDPA_SET_STATUS, &status);
+}
+
 static int vhost_vdpa_reset_device(struct vhost_dev *dev)
 {
     struct vhost_vdpa *v = dev->opaque;
-    int ret;
-    uint8_t status = 0;
 
-    ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &status);
-    trace_vhost_vdpa_reset_device(dev);
     v->suspended = false;
-    return ret;
+    trace_vhost_vdpa_reset_device(dev);
+    return vhost_vdpa_reset_device_fd(vhost_vdpa_dev_fd(dev));
 }
 
 static int vhost_vdpa_get_vq_index(struct vhost_dev *dev, int idx)
@@ -1170,6 +1187,13 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
     return 0;
 }
 
+void vhost_vdpa_reset_status_fd(int fd)
+{
+    vhost_vdpa_reset_device_fd(fd);
+    vhost_vdpa_add_status_fd(fd, VIRTIO_CONFIG_S_ACKNOWLEDGE |
+                                 VIRTIO_CONFIG_S_DRIVER);
+}
+
 static void vhost_vdpa_reset_status(struct vhost_dev *dev)
 {
     struct vhost_vdpa *v = dev->opaque;
@@ -1178,9 +1202,7 @@ static void vhost_vdpa_reset_status(struct vhost_dev *dev)
         return;
     }
 
-    vhost_vdpa_reset_device(dev);
-    vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
-                               VIRTIO_CONFIG_S_DRIVER);
+    vhost_vdpa_reset_status_fd(vhost_vdpa_dev_fd(dev));
     memory_listener_unregister(&v->listener);
 }
 
-- 
2.31.1