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authorAlex Bennée <alex.bennee@linaro.org>2022-03-21 15:30:36 +0000
committerMichael S. Tsirkin <mst@redhat.com>2022-05-16 04:38:40 -0400
commit56534930b5cd3a6c7259cfeba69f08ba28c8f62a (patch)
tree9792a01ca459e6134ae734e797384b59cf154c20 /hw
parent27351992bf238f669dd08655d31ad111905bf899 (diff)
hw/virtio/vhost-user: don't suppress F_CONFIG when supported
Previously we would silently suppress VHOST_USER_PROTOCOL_F_CONFIG during the protocol negotiation if the QEMU stub hadn't implemented the vhost_dev_config_notifier. However this isn't the only way we can handle config messages, the existing vdc->get/set_config can do this as well. Lightly re-factor the code to check for both potential methods and instead of silently squashing the feature error out. It is unlikely that a vhost-user backend expecting to handle CONFIG messages will behave correctly if they never get sent. Fixes: 1c3e5a2617 ("vhost-user: back SET/GET_CONFIG requests with a protocol feature") Cc: Maxime Coquelin <maxime.coquelin@redhat.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20220321153037.3622127-13-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/scsi/vhost-user-scsi.c1
-rw-r--r--hw/virtio/vhost-user.c46
2 files changed, 34 insertions, 13 deletions
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index 1b2f7eed98..9be21d07ee 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -121,6 +121,7 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
vsc->dev.backend_features = 0;
vqs = vsc->dev.vqs;
+ s->vhost_user.supports_config = true;
ret = vhost_dev_init(&vsc->dev, &s->vhost_user,
VHOST_BACKEND_TYPE_USER, 0, errp);
if (ret < 0) {
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 6c8f722262..b0d417651d 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1949,14 +1949,15 @@ static int vhost_user_postcopy_notifier(NotifierWithReturn *notifier,
static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
Error **errp)
{
- uint64_t features, protocol_features, ram_slots;
+ uint64_t features, ram_slots;
struct vhost_user *u;
+ VhostUserState *vus = (VhostUserState *) opaque;
int err;
assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
u = g_new0(struct vhost_user, 1);
- u->user = opaque;
+ u->user = vus;
u->dev = dev;
dev->opaque = u;
@@ -1967,6 +1968,10 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
}
if (virtio_has_feature(features, VHOST_USER_F_PROTOCOL_FEATURES)) {
+ bool supports_f_config = vus->supports_config ||
+ (dev->config_ops && dev->config_ops->vhost_dev_config_notifier);
+ uint64_t protocol_features;
+
dev->backend_features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
err = vhost_user_get_u64(dev, VHOST_USER_GET_PROTOCOL_FEATURES,
@@ -1976,19 +1981,34 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
return -EPROTO;
}
- dev->protocol_features =
- protocol_features & VHOST_USER_PROTOCOL_FEATURE_MASK;
-
- if (!dev->config_ops || !dev->config_ops->vhost_dev_config_notifier) {
- /* Don't acknowledge CONFIG feature if device doesn't support it */
- dev->protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG);
- } else if (!(protocol_features &
- (1ULL << VHOST_USER_PROTOCOL_F_CONFIG))) {
- error_setg(errp, "Device expects VHOST_USER_PROTOCOL_F_CONFIG "
- "but backend does not support it.");
- return -EINVAL;
+ /*
+ * We will use all the protocol features we support - although
+ * we suppress F_CONFIG if we know QEMUs internal code can not support
+ * it.
+ */
+ protocol_features &= VHOST_USER_PROTOCOL_FEATURE_MASK;
+
+ if (supports_f_config) {
+ if (!virtio_has_feature(protocol_features,
+ VHOST_USER_PROTOCOL_F_CONFIG)) {
+ error_setg(errp, "vhost-user device %s expecting "
+ "VHOST_USER_PROTOCOL_F_CONFIG but the vhost-user backend does "
+ "not support it.", dev->vdev->name);
+ return -EPROTO;
+ }
+ } else {
+ if (virtio_has_feature(protocol_features,
+ VHOST_USER_PROTOCOL_F_CONFIG)) {
+ warn_reportf_err(*errp, "vhost-user backend supports "
+ "VHOST_USER_PROTOCOL_F_CONFIG for "
+ "device %s but QEMU does not.",
+ dev->vdev->name);
+ protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG);
+ }
}
+ /* final set of protocol features */
+ dev->protocol_features = protocol_features;
err = vhost_user_set_protocol_features(dev, dev->protocol_features);
if (err < 0) {
error_setg_errno(errp, EPROTO, "vhost_backend_init failed");