---
docs/interop/vhost-user.txt | 21 ++++++++++++---------
hw/virtio/vhost-user.c | 22 ++++++++++++++++++++++
2 files changed, 34 insertions(+), 9 deletions(-)
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
index c058c407df..534caab18a 100644
--- a/docs/interop/vhost-user.txt
+++ b/docs/interop/vhost-user.txt
@@ -379,6 +379,7 @@ Protocol features
#define VHOST_USER_PROTOCOL_F_CROSS_ENDIAN 6
#define VHOST_USER_PROTOCOL_F_CRYPTO_SESSION 7
#define VHOST_USER_PROTOCOL_F_PAGEFAULT 8
+#define VHOST_USER_PROTOCOL_F_CONFIG 9
Master message types
--------------------
@@ -664,7 +665,8 @@ Master message types
Master payload: virtio device config space
Slave payload: virtio device config space
- Submitted by the vhost-user master to fetch the contents of the virtio
+ When VHOST_USER_PROTOCOL_F_CONFIG is negotiated, this message is
+ submitted by the vhost-user master to fetch the contents of the virtio
device configuration space, vhost-user slave's payload size MUST match
master's request, vhost-user slave uses zero length of payload to
indicate an error to vhost-user master. The vhost-user master may
@@ -677,7 +679,8 @@ Master message types
Master payload: virtio device config space
Slave payload: N/A
- Submitted by the vhost-user master when the Guest changes the virtio
+ When VHOST_USER_PROTOCOL_F_CONFIG is negotiated, this message is
+ submitted by the vhost-user master when the Guest changes the virtio
device configuration space and also can be used for live migration
on the destination host. The vhost-user slave must check the flags
field, and slaves MUST NOT accept SET_CONFIG for read-only
@@ -766,13 +769,13 @@ Slave message types
Slave payload: N/A
Master payload: N/A
- Vhost-user slave sends such messages to notify that the virtio device's
- configuration space has changed, for those host devices which can support
- such feature, host driver can send VHOST_USER_GET_CONFIG message to
slave
- to get the latest content. If VHOST_USER_PROTOCOL_F_REPLY_ACK is
- negotiated, and slave set the VHOST_USER_NEED_REPLY flag, master must
- respond with zero when operation is successfully completed, or non-zero
- otherwise.
+ When VHOST_USER_PROTOCOL_F_CONFIG is negotiated, vhost-user slave
sends
+ such messages to notify that the virtio device's configuration space has
+ changed, for those host devices which can support such feature, host
+ driver can send VHOST_USER_GET_CONFIG message to slave to get the latest
+ content. If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, and slave
set
+ the VHOST_USER_NEED_REPLY flag, master must respond with zero when
+ operation is successfully completed, or non-zero otherwise.
VHOST_USER_PROTOCOL_F_REPLY_ACK:
-------------------------------
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 44aea5c0a8..cc8a24aa31 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -46,6 +46,7 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6,
VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7,
VHOST_USER_PROTOCOL_F_PAGEFAULT = 8,
+ VHOST_USER_PROTOCOL_F_CONFIG = 9,
VHOST_USER_PROTOCOL_F_MAX
};
@@ -1211,6 +1212,17 @@ static int vhost_user_init(struct vhost_dev *dev, void
*opaque)
dev->protocol_features =
protocol_features & VHOST_USER_PROTOCOL_FEATURE_MASK;
+
+ if (!dev->config_ops || !dev->config_ops->vhost_dev_config_notifier) {
+ /* Dont 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_report("Device expects VHOST_USER_PROTOCOL_F_CONFIG "
+ "but backend does not support it.");
+ return -1;
+ }
+
err = vhost_user_set_protocol_features(dev, dev->protocol_features);
if (err < 0) {
return err;
@@ -1405,6 +1417,11 @@ static int vhost_user_get_config(struct vhost_dev
*dev, uint8_t *config,
.hdr.size = VHOST_USER_CONFIG_HDR_SIZE + config_len,
};
+ if (!virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_CONFIG)) {
+ return -1;
+ }
+
if (config_len > VHOST_USER_MAX_CONFIG_SIZE) {
return -1;
}
@@ -1448,6 +1465,11 @@ static int vhost_user_set_config(struct vhost_dev
*dev, const uint8_t *data,
.hdr.size = VHOST_USER_CONFIG_HDR_SIZE + size,
};
+ if (!virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_CONFIG)) {
+ return -1;
+ }
+
if (reply_supported) {
msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
}
--
2.14.3