Re: [PATCH for 8.1 v2 2/6] vdpa: add vhost_vdpa_reset_status_fd

[Stefano Garzarella <sgarzare@redhat.com>]

On Thu, Mar 23, 2023 at 08:54:00PM +0100, Eugenio Pérez wrote:
>This allows to reset a vhost-vdpa device from external subsystems like
>vhost-net, since it does not have any struct vhost_dev by the time we
>need to use it.
>
>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(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

>
>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
>