Getting it ahead at initialization time instead of start time allows
decision making independent of device status, while reducing failure
possibility in starting device or during migration.
Adding function vhost_vdpa_probe_desc_group() for that end. This
function will be used to probe the descriptor group for data vqs.
Signed-off-by: Si-Wei Liu <si-wei....@oracle.com>
---
net/vhost-vdpa.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 89 insertions(+)
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 887c329..0cf3147 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -1688,6 +1688,95 @@ out:
return r;
}
+static int vhost_vdpa_probe_desc_group(int device_fd, uint64_t features,
+ int vq_index, int64_t *desc_grpidx,
+ Error **errp)
+{
+ uint64_t backend_features;
+ int64_t vq_group, desc_group;
+ uint8_t saved_status = 0;
+ uint8_t status = 0;
+ int r;
+
+ ERRP_GUARD();
+
+ r = ioctl(device_fd, VHOST_GET_BACKEND_FEATURES, &backend_features);
+ if (unlikely(r < 0)) {
+ error_setg_errno(errp, errno, "Cannot get vdpa backend_features");
+ return r;
+ }
+
+ if (!(backend_features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID))) {
+ return 0;
+ }
+
+ if (!(backend_features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID))) {
+ return 0;
+ }
+
+ r = ioctl(device_fd, VHOST_VDPA_GET_STATUS, &saved_status);
+ if (unlikely(r)) {
+ error_setg_errno(errp, -r, "Cannot get device status");
+ goto out;
+ }
+
+ r = ioctl(device_fd, VHOST_VDPA_SET_STATUS, &status);
+ if (unlikely(r)) {
+ error_setg_errno(errp, -r, "Cannot reset device");
+ goto out;
+ }
+
+ r = ioctl(device_fd, VHOST_SET_FEATURES, &features);
+ if (unlikely(r)) {
+ error_setg_errno(errp, errno, "Cannot set features");
+ }
+
+ status = VIRTIO_CONFIG_S_ACKNOWLEDGE |
+ VIRTIO_CONFIG_S_DRIVER |
+ VIRTIO_CONFIG_S_FEATURES_OK;
+
+ r = ioctl(device_fd, VHOST_VDPA_SET_STATUS, &status);
+ if (unlikely(r)) {
+ error_setg_errno(errp, -r, "Cannot set device status");
+ goto out;
+ }
+
+ vq_group = vhost_vdpa_get_vring_group(device_fd, vq_index, errp);
+ if (unlikely(vq_group < 0)) {
+ if (vq_group != -ENOTSUP) {
+ r = vq_group;
+ goto out;
+ }
+
+ /*
+ * The kernel report VHOST_BACKEND_F_IOTLB_ASID if the vdpa frontend
+ * support ASID even if the parent driver does not.
+ */
+ error_free(*errp);
+ *errp = NULL;
+ r = 0;
+ goto out;
+ }
+
+ desc_group = vhost_vdpa_get_vring_desc_group(device_fd, vq_index,
+ errp);
+ if (unlikely(desc_group < 0)) {
+ r = desc_group;
+ goto out;
+ } else if (desc_group != vq_group) {
+ *desc_grpidx = desc_group;
+ }
+ r = 1;
+
+out:
+ status = 0;
+ ioctl(device_fd, VHOST_VDPA_SET_STATUS, &status);
+ if (saved_status) {
+ ioctl(device_fd, VHOST_VDPA_SET_STATUS, &saved_status);
+ }
+ return r;
+}
+
static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
const char *device,
const char *name,
--
1.8.3.1
