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-rw-r--r--docs/specs/vhost-user.txt37
-rw-r--r--hw/net/vhost_net.c2
-rw-r--r--hw/virtio/vhost-user.c31
-rw-r--r--include/hw/virtio/vhost.h1
4 files changed, 71 insertions, 0 deletions
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 650bb18..70da3b1 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -113,6 +113,7 @@ message replies. Most of the requests don't require replies. Here is a list of
the ones that do:
* VHOST_GET_FEATURES
+ * VHOST_GET_PROTOCOL_FEATURES
* VHOST_GET_VRING_BASE
There are several messages that the master sends with file descriptors passed
@@ -127,6 +128,13 @@ in the ancillary data:
If Master is unable to send the full message or receives a wrong reply it will
close the connection. An optional reconnection mechanism can be implemented.
+Any protocol extensions are gated by protocol feature bits,
+which allows full backwards compatibility on both master
+and slave.
+As older slaves don't support negotiating protocol features,
+a feature bit was dedicated for this purpose:
+#define VHOST_USER_F_PROTOCOL_FEATURES 30
+
Message types
-------------
@@ -138,6 +146,8 @@ Message types
Slave payload: u64
Get from the underlying vhost implementation the features bitmask.
+ Feature bit VHOST_USER_F_PROTOCOL_FEATURES signals slave support for
+ VHOST_USER_GET_PROTOCOL_FEATURES and VHOST_USER_SET_PROTOCOL_FEATURES.
* VHOST_USER_SET_FEATURES
@@ -146,6 +156,33 @@ Message types
Master payload: u64
Enable features in the underlying vhost implementation using a bitmask.
+ Feature bit VHOST_USER_F_PROTOCOL_FEATURES signals slave support for
+ VHOST_USER_GET_PROTOCOL_FEATURES and VHOST_USER_SET_PROTOCOL_FEATURES.
+
+ * VHOST_USER_GET_PROTOCOL_FEATURES
+
+ Id: 15
+ Equivalent ioctl: VHOST_GET_FEATURES
+ Master payload: N/A
+ Slave payload: u64
+
+ Get the protocol feature bitmask from the underlying vhost implementation.
+ Only legal if feature bit VHOST_USER_F_PROTOCOL_FEATURES is present in
+ VHOST_USER_GET_FEATURES.
+ Note: slave that reported VHOST_USER_F_PROTOCOL_FEATURES must support
+ this message even before VHOST_USER_SET_FEATURES was called.
+
+ * VHOST_USER_SET_PROTOCOL_FEATURES
+
+ Id: 16
+ Ioctl: VHOST_SET_FEATURES
+ Master payload: u64
+
+ Enable protocol features in the underlying vhost implementation.
+ Only legal if feature bit VHOST_USER_F_PROTOCOL_FEATURES is present in
+ VHOST_USER_GET_FEATURES.
+ Note: slave that reported VHOST_USER_F_PROTOCOL_FEATURES must support
+ this message even before VHOST_USER_SET_FEATURES was called.
* VHOST_USER_SET_OWNER
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 1d76b94..9d32d76 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -152,8 +152,10 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
net->dev.backend_features = qemu_has_vnet_hdr(options->net_backend)
? 0 : (1ULL << VHOST_NET_F_VIRTIO_NET_HDR);
net->backend = r;
+ net->dev.protocol_features = 0;
} else {
net->dev.backend_features = 0;
+ net->dev.protocol_features = 0;
net->backend = -1;
}
net->nc = options->net_backend;
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 13677ac..7fe35c6 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -24,6 +24,8 @@
#include <linux/vhost.h>
#define VHOST_MEMORY_MAX_NREGIONS 8
+#define VHOST_USER_F_PROTOCOL_FEATURES 30
+#define VHOST_USER_PROTOCOL_FEATURE_MASK 0x0ULL
typedef enum VhostUserRequest {
VHOST_USER_NONE = 0,
@@ -41,6 +43,8 @@ typedef enum VhostUserRequest {
VHOST_USER_SET_VRING_KICK = 12,
VHOST_USER_SET_VRING_CALL = 13,
VHOST_USER_SET_VRING_ERR = 14,
+ VHOST_USER_GET_PROTOCOL_FEATURES = 15,
+ VHOST_USER_SET_PROTOCOL_FEATURES = 16,
VHOST_USER_MAX
} VhostUserRequest;
@@ -206,11 +210,13 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
switch (msg_request) {
case VHOST_USER_GET_FEATURES:
+ case VHOST_USER_GET_PROTOCOL_FEATURES:
need_reply = 1;
break;
case VHOST_USER_SET_FEATURES:
case VHOST_USER_SET_LOG_BASE:
+ case VHOST_USER_SET_PROTOCOL_FEATURES:
msg.u64 = *((__u64 *) arg);
msg.size = sizeof(m.u64);
break;
@@ -308,6 +314,7 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
switch (msg_request) {
case VHOST_USER_GET_FEATURES:
+ case VHOST_USER_GET_PROTOCOL_FEATURES:
if (msg.size != sizeof(m.u64)) {
error_report("Received bad msg size.");
return -1;
@@ -333,10 +340,34 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
static int vhost_user_init(struct vhost_dev *dev, void *opaque)
{
+ unsigned long long features;
+ int err;
+
assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
dev->opaque = opaque;
+ err = vhost_user_call(dev, VHOST_USER_GET_FEATURES, &features);
+ if (err < 0) {
+ return err;
+ }
+
+ if (virtio_has_feature(features, VHOST_USER_F_PROTOCOL_FEATURES)) {
+ dev->backend_features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
+
+ err = vhost_user_call(dev, VHOST_USER_GET_PROTOCOL_FEATURES, &features);
+ if (err < 0) {
+ return err;
+ }
+
+ dev->protocol_features = features & VHOST_USER_PROTOCOL_FEATURE_MASK;
+ err = vhost_user_call(dev, VHOST_USER_SET_PROTOCOL_FEATURES,
+ &dev->protocol_features);
+ if (err < 0) {
+ return err;
+ }
+ }
+
return 0;
}
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index dd51050..6467c73 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -47,6 +47,7 @@ struct vhost_dev {
unsigned long long features;
unsigned long long acked_features;
unsigned long long backend_features;
+ unsigned long long protocol_features;
bool started;
bool log_enabled;
unsigned long long log_size;
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