Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

- Supporting changing 'file' in x-blockdev-reopen
- ssh: add support for sha256 host key fingerprints
- vhost-user-blk: Implement reconnection during realize
- introduce QEMU_AUTO_VFREE
- Don't require password of encrypted backing file for image creation
- Code cleanups

# gpg: Signature made Wed 30 Jun 2021 17:00:55 BST
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (24 commits)
  vhost-user-blk: Implement reconnection during realize
  vhost-user-blk: Factor out vhost_user_blk_realize_connect()
  vhost: Distinguish errors in vhost_dev_get_config()
  vhost-user-blk: Add Error parameter to vhost_user_blk_start()
  vhost: Return 0/-errno in vhost_dev_init()
  vhost: Distinguish errors in vhost_backend_init()
  vhost: Add Error parameter to vhost_dev_init()
  block/ssh: add support for sha256 host key fingerprints
  block/commit: use QEMU_AUTO_VFREE
  introduce QEMU_AUTO_VFREE
  iotests: Test replacing files with x-blockdev-reopen
  block: Allow changing bs->file on reopen
  block: BDRVReopenState: drop replace_backing_bs field
  block: move supports_backing check to bdrv_set_file_or_backing_noperm()
  block: bdrv_reopen_parse_backing(): simplify handling implicit filters
  block: bdrv_reopen_parse_backing(): don't check frozen child
  block: bdrv_reopen_parse_backing(): don't check aio context
  block: introduce bdrv_set_file_or_backing_noperm()
  block: introduce bdrv_remove_file_or_backing_child()
  block: comment graph-modifying function not updating permissions
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

13 files changed, 164 insertions, 110 deletions

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index c6210fad0c..ba13cb87e5 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -31,6 +31,8 @@
 #include "sysemu/sysemu.h"
 #include "sysemu/runstate.h"
 
+#define REALIZE_CONNECTION_RETRIES 3
+
 static const int user_feature_bits[] = {
     VIRTIO_BLK_F_SIZE_MAX,
     VIRTIO_BLK_F_SEG_MAX,
@@ -91,11 +93,13 @@ static int vhost_user_blk_handle_config_change(struct vhost_dev *dev)
     int ret;
     struct virtio_blk_config blkcfg;
     VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
+    Error *local_err = NULL;
 
     ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
-                               sizeof(struct virtio_blk_config));
+                               sizeof(struct virtio_blk_config),
+                               &local_err);
     if (ret < 0) {
-        error_report("get config space failed");
+        error_report_err(local_err);
         return -1;
     }
 
@@ -113,7 +117,7 @@ const VhostDevConfigOps blk_ops = {
     .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
 };
 
-static int vhost_user_blk_start(VirtIODevice *vdev)
+static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
@@ -121,19 +125,19 @@ static int vhost_user_blk_start(VirtIODevice *vdev)
     int i, ret;
 
     if (!k->set_guest_notifiers) {
-        error_report("binding does not support guest notifiers");
+        error_setg(errp, "binding does not support guest notifiers");
         return -ENOSYS;
     }
 
     ret = vhost_dev_enable_notifiers(&s->dev, vdev);
     if (ret < 0) {
-        error_report("Error enabling host notifiers: %d", -ret);
+        error_setg_errno(errp, -ret, "Error enabling host notifiers");
         return ret;
     }
 
     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
     if (ret < 0) {
-        error_report("Error binding guest notifier: %d", -ret);
+        error_setg_errno(errp, -ret, "Error binding guest notifier");
         goto err_host_notifiers;
     }
 
@@ -141,27 +145,27 @@ static int vhost_user_blk_start(VirtIODevice *vdev)
 
     ret = vhost_dev_prepare_inflight(&s->dev, vdev);
     if (ret < 0) {
-        error_report("Error set inflight format: %d", -ret);
+        error_setg_errno(errp, -ret, "Error setting inflight format");
         goto err_guest_notifiers;
     }
 
     if (!s->inflight->addr) {
         ret = vhost_dev_get_inflight(&s->dev, s->queue_size, s->inflight);
         if (ret < 0) {
-            error_report("Error get inflight: %d", -ret);
+            error_setg_errno(errp, -ret, "Error getting inflight");
             goto err_guest_notifiers;
         }
     }
 
     ret = vhost_dev_set_inflight(&s->dev, s->inflight);
     if (ret < 0) {
-        error_report("Error set inflight: %d", -ret);
+        error_setg_errno(errp, -ret, "Error setting inflight");
         goto err_guest_notifiers;
     }
 
     ret = vhost_dev_start(&s->dev, vdev);
     if (ret < 0) {
-        error_report("Error starting vhost: %d", -ret);
+        error_setg_errno(errp, -ret, "Error starting vhost");
         goto err_guest_notifiers;
     }
     s->started_vu = true;
@@ -214,6 +218,7 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
     bool should_start = virtio_device_started(vdev, status);
+    Error *local_err = NULL;
     int ret;
 
     if (!vdev->vm_running) {
@@ -229,10 +234,9 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
     }
 
     if (should_start) {
-        ret = vhost_user_blk_start(vdev);
+        ret = vhost_user_blk_start(vdev, &local_err);
         if (ret < 0) {
-            error_report("vhost-user-blk: vhost start failed: %s",
-                         strerror(-ret));
+            error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
             qemu_chr_fe_disconnect(&s->chardev);
         }
     } else {
@@ -270,6 +274,7 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
 static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
+    Error *local_err = NULL;
     int i, ret;
 
     if (!vdev->start_on_kick) {
@@ -287,10 +292,9 @@ static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
     /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
      * vhost here instead of waiting for .set_status().
      */
-    ret = vhost_user_blk_start(vdev);
+    ret = vhost_user_blk_start(vdev, &local_err);
     if (ret < 0) {
-        error_report("vhost-user-blk: vhost start failed: %s",
-                     strerror(-ret));
+        error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
         qemu_chr_fe_disconnect(&s->chardev);
         return;
     }
@@ -332,17 +336,16 @@ 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;
     }
 
     /* restore vhost state */
     if (virtio_device_started(vdev, vdev->status)) {
-        ret = vhost_user_blk_start(vdev);
+        ret = vhost_user_blk_start(vdev, errp);
         if (ret < 0) {
-            error_setg_errno(errp, -ret, "vhost start failed");
             return ret;
         }
     }
@@ -422,10 +425,42 @@ static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
     }
 }
 
+static int vhost_user_blk_realize_connect(VHostUserBlk *s, Error **errp)
+{
+    DeviceState *dev = &s->parent_obj.parent_obj;
+    int ret;
+
+    s->connected = false;
+
+    ret = qemu_chr_fe_wait_connected(&s->chardev, errp);
+    if (ret < 0) {
+        return ret;
+    }
+
+    ret = vhost_user_blk_connect(dev, errp);
+    if (ret < 0) {
+        qemu_chr_fe_disconnect(&s->chardev);
+        return ret;
+    }
+    assert(s->connected);
+
+    ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
+                               sizeof(struct virtio_blk_config), errp);
+    if (ret < 0) {
+        qemu_chr_fe_disconnect(&s->chardev);
+        vhost_dev_cleanup(&s->dev);
+        return ret;
+    }
+
+    return 0;
+}
+
 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_GUARD();
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
+    int retries;
     int i, ret;
 
     if (!s->chardev.chr) {
@@ -466,23 +501,20 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 
     s->inflight = g_new0(struct vhost_inflight, 1);
     s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
-    s->connected = false;
-
-    if (qemu_chr_fe_wait_connected(&s->chardev, errp) < 0) {
-        goto virtio_err;
-    }
 
-    if (vhost_user_blk_connect(dev, errp) < 0) {
-        qemu_chr_fe_disconnect(&s->chardev);
-        goto virtio_err;
-    }
-    assert(s->connected);
+    retries = REALIZE_CONNECTION_RETRIES;
+    assert(!*errp);
+    do {
+        if (*errp) {
+            error_prepend(errp, "Reconnecting after error: ");
+            error_report_err(*errp);
+            *errp = NULL;
+        }
+        ret = vhost_user_blk_realize_connect(s, errp);
+    } while (ret == -EPROTO && retries--);
 
-    ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
-                               sizeof(struct virtio_blk_config));
     if (ret < 0) {
-        error_setg(errp, "vhost-user-blk: get block config failed");
-        goto vhost_err;
+        goto virtio_err;
     }
 
     /* we're fully initialized, now we can operate, so add the handler */
@@ -491,8 +523,6 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
                              NULL, true);
     return;
 
-vhost_err:
-    vhost_dev_cleanup(&s->dev);
 virtio_err:
     g_free(s->vhost_vqs);
     s->vhost_vqs = NULL;
diff --git a/hw/display/vhost-user-gpu.c b/hw/display/vhost-user-gpu.c
index 6cdaa1c73b..389199e6ca 100644
--- a/hw/display/vhost-user-gpu.c
+++ b/hw/display/vhost-user-gpu.c
@@ -415,14 +415,16 @@ vhost_user_gpu_get_config(VirtIODevice *vdev, uint8_t *config_data)
     VirtIOGPUBase *b = VIRTIO_GPU_BASE(vdev);
     struct virtio_gpu_config *vgconfig =
         (struct virtio_gpu_config *)config_data;
+    Error *local_err = NULL;
     int ret;
 
     memset(config_data, 0, sizeof(struct virtio_gpu_config));
 
     ret = vhost_dev_get_config(&g->vhost->dev,
-                               config_data, sizeof(struct virtio_gpu_config));
+                               config_data, sizeof(struct virtio_gpu_config),
+                               &local_err);
     if (ret) {
-        error_report("vhost-user-gpu: get device config space failed");
+        error_report_err(local_err);
         return;
     }
 
diff --git a/hw/input/vhost-user-input.c b/hw/input/vhost-user-input.c
index 63984a8ba7..273e96a7b1 100644
--- a/hw/input/vhost-user-input.c
+++ b/hw/input/vhost-user-input.c
@@ -49,13 +49,15 @@ static void vhost_input_get_config(VirtIODevice *vdev, uint8_t *config_data)
 {
     VirtIOInput *vinput = VIRTIO_INPUT(vdev);
     VHostUserInput *vhi = VHOST_USER_INPUT(vdev);
+    Error *local_err = NULL;
     int ret;
 
     memset(config_data, 0, vinput->cfg_size);
 
-    ret = vhost_dev_get_config(&vhi->vhost->dev, config_data, vinput->cfg_size);
+    ret = vhost_dev_get_config(&vhi->vhost->dev, config_data, vinput->cfg_size,
+                               &local_err);
     if (ret) {
-        error_report("vhost-user-input: get device config space failed");
+        error_report_err(local_err);
         return;
     }
 }
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 44c1ed92dc..10a7780a13 100644
--- a/hw/net/vhost_net.c
+++ b/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"
 
@@ -116,7 +117,7 @@ uint64_t vhost_net_get_features(struct vhost_net *net, uint64_t features)
 int vhost_net_get_config(struct vhost_net *net,  uint8_t *config,
                          uint32_t config_len)
 {
-    return vhost_dev_get_config(&net->dev, config, config_len);
+    return vhost_dev_get_config(&net->dev, config, config_len, NULL);
 }
 int vhost_net_set_config(struct vhost_net *net, const uint8_t *data,
                          uint32_t offset, uint32_t size, uint32_t flags)
@@ -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) {
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index 4d70fa036b..8c611bfd2d 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/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;
     }
 
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index 4666019442..1b2f7eed98 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/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;
     }
 
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 31b33bde37..594d770b75 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -24,13 +24,15 @@ static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
                              void *arg)
 {
     int fd = (uintptr_t) dev->opaque;
+    int ret;
 
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
 
-    return ioctl(fd, request, arg);
+    ret = ioctl(fd, request, arg);
+    return ret < 0 ? -errno : ret;
 }
 
-static int vhost_kernel_init(struct vhost_dev *dev, void *opaque)
+static int vhost_kernel_init(struct vhost_dev *dev, void *opaque, Error **errp)
 {
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
 
diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
index 6f7f91533d..c595957983 100644
--- a/hw/virtio/vhost-user-fs.c
+++ b/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;
     }
 
diff --git a/hw/virtio/vhost-user-vsock.c b/hw/virtio/vhost-user-vsock.c
index a6f08c26b9..6095ed7349 100644
--- a/hw/virtio/vhost-user-vsock.c
+++ b/hw/virtio/vhost-user-vsock.c
@@ -34,10 +34,12 @@ static void vuv_get_config(VirtIODevice *vdev, uint8_t *config)
 static int vuv_handle_config_change(struct vhost_dev *dev)
 {
     VHostUserVSock *vsock = VHOST_USER_VSOCK(dev->vdev);
+    Error *local_err = NULL;
     int ret = vhost_dev_get_config(dev, (uint8_t *)&vsock->vsockcfg,
-                                   sizeof(struct virtio_vsock_config));
+                                   sizeof(struct virtio_vsock_config),
+                                   &local_err);
     if (ret < 0) {
-        error_report("get config space failed");
+        error_report_err(local_err);
         return -1;
     }
 
@@ -108,16 +110,14 @@ 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;
     }
 
     ret = vhost_dev_get_config(&vvc->vhost_dev, (uint8_t *)&vsock->vsockcfg,
-                               sizeof(struct virtio_vsock_config));
+                               sizeof(struct virtio_vsock_config), errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "get config space failed");
         goto err_vhost_dev;
     }
 
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index ee57abe045..1ac4a2ebec 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1353,7 +1353,11 @@ static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64)
 
 static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features)
 {
-    return vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features);
+    if (vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features) < 0) {
+        return -EPROTO;
+    }
+
+    return 0;
 }
 
 static int vhost_user_set_owner(struct vhost_dev *dev)
@@ -1364,7 +1368,7 @@ static int vhost_user_set_owner(struct vhost_dev *dev)
     };
 
     if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
-        return -1;
+        return -EPROTO;
     }
 
     return 0;
@@ -1856,7 +1860,8 @@ static int vhost_user_postcopy_notifier(NotifierWithReturn *notifier,
     return 0;
 }
 
-static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
+static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
+                                   Error **errp)
 {
     uint64_t features, protocol_features, ram_slots;
     struct vhost_user *u;
@@ -1880,7 +1885,7 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
         err = vhost_user_get_u64(dev, VHOST_USER_GET_PROTOCOL_FEATURES,
                                  &protocol_features);
         if (err < 0) {
-            return err;
+            return -EPROTO;
         }
 
         dev->protocol_features =
@@ -1891,14 +1896,14 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
             dev->protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG);
         } else if (!(protocol_features &
                     (1ULL << VHOST_USER_PROTOCOL_F_CONFIG))) {
-            error_report("Device expects VHOST_USER_PROTOCOL_F_CONFIG "
-                    "but backend does not support it.");
-            return -1;
+            error_setg(errp, "Device expects VHOST_USER_PROTOCOL_F_CONFIG "
+                       "but backend does not support it.");
+            return -EINVAL;
         }
 
         err = vhost_user_set_protocol_features(dev, dev->protocol_features);
         if (err < 0) {
-            return err;
+            return -EPROTO;
         }
 
         /* query the max queues we support if backend supports Multiple Queue */
@@ -1906,12 +1911,12 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
             err = vhost_user_get_u64(dev, VHOST_USER_GET_QUEUE_NUM,
                                      &dev->max_queues);
             if (err < 0) {
-                return err;
+                return -EPROTO;
             }
         }
         if (dev->num_queues && dev->max_queues < dev->num_queues) {
-            error_report("The maximum number of queues supported by the "
-                         "backend is %" PRIu64, dev->max_queues);
+            error_setg(errp, "The maximum number of queues supported by the "
+                       "backend is %" PRIu64, dev->max_queues);
             return -EINVAL;
         }
 
@@ -1920,9 +1925,9 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
                     VHOST_USER_PROTOCOL_F_SLAVE_REQ) &&
                  virtio_has_feature(dev->protocol_features,
                     VHOST_USER_PROTOCOL_F_REPLY_ACK))) {
-            error_report("IOMMU support requires reply-ack and "
-                         "slave-req protocol features.");
-            return -1;
+            error_setg(errp, "IOMMU support requires reply-ack and "
+                       "slave-req protocol features.");
+            return -EINVAL;
         }
 
         /* get max memory regions if backend supports configurable RAM slots */
@@ -1932,15 +1937,15 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
         } else {
             err = vhost_user_get_max_memslots(dev, &ram_slots);
             if (err < 0) {
-                return err;
+                return -EPROTO;
             }
 
             if (ram_slots < u->user->memory_slots) {
-                error_report("The backend specified a max ram slots limit "
-                             "of %" PRIu64", when the prior validated limit was %d. "
-                             "This limit should never decrease.", ram_slots,
-                             u->user->memory_slots);
-                return -1;
+                error_setg(errp, "The backend specified a max ram slots limit "
+                           "of %" PRIu64", when the prior validated limit was "
+                           "%d. This limit should never decrease.", ram_slots,
+                           u->user->memory_slots);
+                return -EINVAL;
             }
 
             u->user->memory_slots = MIN(ram_slots, VHOST_USER_MAX_RAM_SLOTS);
@@ -1958,7 +1963,7 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
     if (dev->vq_index == 0) {
         err = vhost_setup_slave_channel(dev);
         if (err < 0) {
-            return err;
+            return -EPROTO;
         }
     }
 
@@ -2112,7 +2117,7 @@ static void vhost_user_set_iotlb_callback(struct vhost_dev *dev, int enabled)
 }
 
 static int vhost_user_get_config(struct vhost_dev *dev, uint8_t *config,
-                                 uint32_t config_len)
+                                 uint32_t config_len, Error **errp)
 {
     VhostUserMsg msg = {
         .hdr.request = VHOST_USER_GET_CONFIG,
@@ -2122,32 +2127,32 @@ static int vhost_user_get_config(struct vhost_dev *dev, uint8_t *config,
 
     if (!virtio_has_feature(dev->protocol_features,
                 VHOST_USER_PROTOCOL_F_CONFIG)) {
-        return -1;
+        error_setg(errp, "VHOST_USER_PROTOCOL_F_CONFIG not supported");
+        return -EINVAL;
     }
 
-    if (config_len > VHOST_USER_MAX_CONFIG_SIZE) {
-        return -1;
-    }
+    assert(config_len <= VHOST_USER_MAX_CONFIG_SIZE);
 
     msg.payload.config.offset = 0;
     msg.payload.config.size = config_len;
     if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
-        return -1;
+        return -EPROTO;
     }
 
     if (vhost_user_read(dev, &msg) < 0) {
-        return -1;
+        return -EPROTO;
     }
 
     if (msg.hdr.request != VHOST_USER_GET_CONFIG) {
-        error_report("Received unexpected msg type. Expected %d received %d",
-                     VHOST_USER_GET_CONFIG, msg.hdr.request);
-        return -1;
+        error_setg(errp,
+                   "Received unexpected msg type. Expected %d received %d",
+                   VHOST_USER_GET_CONFIG, msg.hdr.request);
+        return -EINVAL;
     }
 
     if (msg.hdr.size != VHOST_USER_CONFIG_HDR_SIZE + config_len) {
-        error_report("Received bad msg size.");
-        return -1;
+        error_setg(errp, "Received bad msg size.");
+        return -EINVAL;
     }
 
     memcpy(config, msg.payload.config.region, config_len);
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 61ba313331..4fa414feea 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -245,10 +245,12 @@ static int vhost_vdpa_call(struct vhost_dev *dev, unsigned long int request,
 {
     struct vhost_vdpa *v = dev->opaque;
     int fd = v->device_fd;
+    int ret;
 
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
 
-    return ioctl(fd, request, arg);
+    ret = ioctl(fd, request, arg);
+    return ret < 0 ? -errno : ret;
 }
 
 static void vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
@@ -265,7 +267,7 @@ static void vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
     vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
 }
 
-static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque)
+static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
 {
     struct vhost_vdpa *v;
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
@@ -521,7 +523,7 @@ static int vhost_vdpa_set_config(struct vhost_dev *dev, const uint8_t *data,
 }
 
 static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config,
-                                   uint32_t config_len)
+                                   uint32_t config_len, Error **errp)
 {
     struct vhost_vdpa_config *v_config;
     unsigned long config_size = offsetof(struct vhost_vdpa_config, buf);
diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
index 8ddfb9abfe..777cafe70d 100644
--- a/hw/virtio/vhost-vsock.c
+++ b/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;
     }
 
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 7b7bde7657..e8f85a5d2d 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1286,11 +1286,12 @@ 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)
 {
+    ERRP_GUARD();
     uint64_t features;
     int i, r, n_initialized_vqs = 0;
-    Error *local_err = NULL;
 
     hdev->vdev = NULL;
     hdev->migration_blocker = NULL;
@@ -1298,26 +1299,30 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     r = vhost_set_backend_type(hdev, backend_type);
     assert(r >= 0);
 
-    r = hdev->vhost_ops->vhost_backend_init(hdev, opaque);
+    r = hdev->vhost_ops->vhost_backend_init(hdev, opaque, errp);
     if (r < 0) {
+        if (!*errp) {
+            error_setg_errno(errp, -r, "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_errno(errp, -r, "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_errno(errp, -r, "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 +1332,7 @@ 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_errno(errp, -r, "Failed to set busyloop timeout");
                 goto fail_busyloop;
             }
         }
@@ -1365,9 +1371,8 @@ 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);
+        r = migrate_add_blocker(hdev->migration_blocker, errp);
+        if (*errp) {
             error_free(hdev->migration_blocker);
             goto fail_busyloop;
         }
@@ -1384,9 +1389,9 @@ 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");
-        r = -1;
+        error_setg(errp, "vhost backend memory slots limit is less"
+                   " than current number of present memory slots");
+        r = -EINVAL;
         goto fail_busyloop;
     }
 
@@ -1557,15 +1562,23 @@ void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
 }
 
 int vhost_dev_get_config(struct vhost_dev *hdev, uint8_t *config,
-                         uint32_t config_len)
+                         uint32_t config_len, Error **errp)
 {
+    ERRP_GUARD();
+    int ret;
+
     assert(hdev->vhost_ops);
 
     if (hdev->vhost_ops->vhost_get_config) {
-        return hdev->vhost_ops->vhost_get_config(hdev, config, config_len);
+        ret = hdev->vhost_ops->vhost_get_config(hdev, config, config_len, errp);
+        if (ret < 0 && !*errp) {
+            error_setg_errno(errp, -ret, "vhost_get_config failed");
+        }
+        return ret;
     }
 
-    return -1;
+    error_setg(errp, "vhost_get_config not implemented");
+    return -ENOTSUP;
 }
 
 int vhost_dev_set_config(struct vhost_dev *hdev, const uint8_t *data,