vhost: Add Error parameter to vhost_dev_init()

This allows callers to return better error messages instead of making
one up while the real error ends up on stderr. Most callers can
immediately make use of this because they already have an Error
parameter themselves. The others just keep printing the error with
error_report_err().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-2-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

backends/cryptodev-vhost.c

@@ -52,6 +52,7 @@ cryptodev_vhost_init(
 {
     int r;
     CryptoDevBackendVhost *crypto;
+    Error *local_err = NULL;
 
     crypto = g_new(CryptoDevBackendVhost, 1);
     crypto->dev.max_queues = 1;
@@ -66,8 +67,10 @@ cryptodev_vhost_init(
     /* vhost-user needs vq_index to initiate a specific queue pair */
     crypto->dev.vq_index = crypto->cc->queue_index * crypto->dev.nvqs;
 
-    r = vhost_dev_init(&crypto->dev, options->opaque, options->backend_type, 0);
+    r = vhost_dev_init(&crypto->dev, options->opaque, options->backend_type, 0,
+                       &local_err);
     if (r < 0) {
+        error_report_err(local_err);
         goto fail;
     }
 

backends/vhost-user.c

@@ -48,9 +48,9 @@ vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
     b->dev.nvqs = nvqs;
     b->dev.vqs = g_new0(struct vhost_virtqueue, nvqs);
 
-    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
+    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
+                         errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "vhost initialization failed");
         return -1;
     }
 

hw/block/vhost-user-blk.c

@@ -332,9 +332,9 @@ static int vhost_user_blk_connect(DeviceState *dev, Error **errp)
 
     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
 
-    ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
+    ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
+                         errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "vhost initialization failed");
         return ret;
     }
 

hw/net/vhost_net.c

@@ -22,6 +22,7 @@
 #include "standard-headers/linux/vhost_types.h"
 #include "hw/virtio/virtio-net.h"
 #include "net/vhost_net.h"
+#include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 
@@ -157,6 +158,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
     bool backend_kernel = options->backend_type == VHOST_BACKEND_TYPE_KERNEL;
     struct vhost_net *net = g_new0(struct vhost_net, 1);
     uint64_t features = 0;
+    Error *local_err = NULL;
 
     if (!options->net_backend) {
         fprintf(stderr, "vhost-net requires net backend to be setup\n");
@@ -187,8 +189,10 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
     }
 
     r = vhost_dev_init(&net->dev, options->opaque,
-                       options->backend_type, options->busyloop_timeout);
+                       options->backend_type, options->busyloop_timeout,
+                       &local_err);
     if (r < 0) {
+        error_report_err(local_err);
         goto fail;
     }
     if (backend_kernel) {

hw/scsi/vhost-scsi.c

@@ -219,10 +219,8 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
     vsc->dev.backend_features = 0;
 
     ret = vhost_dev_init(&vsc->dev, (void *)(uintptr_t)vhostfd,
-                         VHOST_BACKEND_TYPE_KERNEL, 0);
+                         VHOST_BACKEND_TYPE_KERNEL, 0, errp);
     if (ret < 0) {
-        error_setg(errp, "vhost-scsi: vhost initialization failed: %s",
-                   strerror(-ret));
         goto free_vqs;
     }
 

hw/scsi/vhost-user-scsi.c

@@ -122,10 +122,8 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
     vqs = vsc->dev.vqs;
 
     ret = vhost_dev_init(&vsc->dev, &s->vhost_user,
-                         VHOST_BACKEND_TYPE_USER, 0);
+                         VHOST_BACKEND_TYPE_USER, 0, errp);
     if (ret < 0) {
-        error_setg(errp, "vhost-user-scsi: vhost initialization failed: %s",
-                   strerror(-ret));
         goto free_vhost;
     }
 

hw/virtio/vhost-user-fs.c

@@ -235,9 +235,8 @@ static void vuf_device_realize(DeviceState *dev, Error **errp)
     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
-                         VHOST_BACKEND_TYPE_USER, 0);
+                         VHOST_BACKEND_TYPE_USER, 0, errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "vhost_dev_init failed");
         goto err_virtio;
     }
 

hw/virtio/vhost-user-vsock.c

@@ -108,9 +108,8 @@ static void vuv_device_realize(DeviceState *dev, Error **errp)
     vhost_dev_set_config_notifier(&vvc->vhost_dev, &vsock_ops);
 
     ret = vhost_dev_init(&vvc->vhost_dev, &vsock->vhost_user,
-                         VHOST_BACKEND_TYPE_USER, 0);
+                         VHOST_BACKEND_TYPE_USER, 0, errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "vhost_dev_init failed");
         goto err_virtio;
     }
 

hw/virtio/vhost-vsock.c

@@ -170,9 +170,8 @@ static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
     vhost_vsock_common_realize(vdev, "vhost-vsock");
 
     ret = vhost_dev_init(&vvc->vhost_dev, (void *)(uintptr_t)vhostfd,
-                         VHOST_BACKEND_TYPE_KERNEL, 0);
+                         VHOST_BACKEND_TYPE_KERNEL, 0, errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "vhost-vsock: vhost_dev_init failed");
         goto err_virtio;
     }
 

hw/virtio/vhost.c

@@ -1286,7 +1286,8 @@ static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
 }
 
 int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
-                   VhostBackendType backend_type, uint32_t busyloop_timeout)
+                   VhostBackendType backend_type, uint32_t busyloop_timeout,
+                   Error **errp)
 {
     uint64_t features;
     int i, r, n_initialized_vqs = 0;
@@ -1300,24 +1301,26 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
 
     r = hdev->vhost_ops->vhost_backend_init(hdev, opaque);
     if (r < 0) {
+        error_setg(errp, "vhost_backend_init failed");
         goto fail;
     }
 
     r = hdev->vhost_ops->vhost_set_owner(hdev);
     if (r < 0) {
-        VHOST_OPS_DEBUG("vhost_set_owner failed");
+        error_setg(errp, "vhost_set_owner failed");
         goto fail;
     }
 
     r = hdev->vhost_ops->vhost_get_features(hdev, &features);
     if (r < 0) {
-        VHOST_OPS_DEBUG("vhost_get_features failed");
+        error_setg(errp, "vhost_get_features failed");
         goto fail;
     }
 
     for (i = 0; i < hdev->nvqs; ++i, ++n_initialized_vqs) {
         r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i);
         if (r < 0) {
+            error_setg_errno(errp, -r, "Failed to initialize virtqueue %d", i);
             goto fail;
         }
     }
@@ -1327,6 +1330,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
             r = vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i,
                                                      busyloop_timeout);
             if (r < 0) {
+                error_setg(errp, "Failed to set busyloop timeout");
                 goto fail_busyloop;
             }
         }
@@ -1367,7 +1371,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     if (hdev->migration_blocker != NULL) {
         r = migrate_add_blocker(hdev->migration_blocker, &local_err);
         if (local_err) {
-            error_report_err(local_err);
+            error_propagate(errp, local_err);
             error_free(hdev->migration_blocker);
             goto fail_busyloop;
         }
@@ -1384,8 +1388,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
 
     if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
-        error_report("vhost backend memory slots limit is less"
-                " than current number of present memory slots");
+        error_setg(errp, "vhost backend memory slots limit is less"
+                   " than current number of present memory slots");
         r = -1;
         goto fail_busyloop;
     }

include/hw/virtio/vhost.h

@@ -104,7 +104,7 @@ struct vhost_net {
 
 int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
                    VhostBackendType backend_type,
-                   uint32_t busyloop_timeout);
+                   uint32_t busyloop_timeout, Error **errp);
 void vhost_dev_cleanup(struct vhost_dev *hdev);
 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev);
 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev);