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vhost-user: fix legacy cross-endian configurations

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Currently, vhost-user does not implement any means for notifying the
backend about guest endianess. This commit introduces a new message
called VHOST_USER_SET_VRING_ENDIAN which is analogous to the ioctl()
called VHOST_SET_VRING_ENDIAN used for kernel vhost backends. Such
message is necessary for backends supporting legacy (pre-1.0) virtio
devices running in big-endian guests.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Signed-off-by: Mike Cui <cui@nutanix.com>
This commit is contained in:
Felipe Franciosi 2017-06-14 18:44:38 +01:00 • committed by Michael S. Tsirkin
parent 08b9e0ba62
commit 5df04f1762
2 changed files with 37 additions and 2 deletions
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23
hw/virtio/vhost-user.c
View file

@ -33,6 +33,7 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_REPLY_ACK = 3,
VHOST_USER_PROTOCOL_F_NET_MTU = 4,
VHOST_USER_PROTOCOL_F_SLAVE_REQ = 5,
VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6,
VHOST_USER_PROTOCOL_F_MAX
};
@ -63,6 +64,7 @@ typedef enum VhostUserRequest {
VHOST_USER_NET_SET_MTU = 20,
VHOST_USER_SET_SLAVE_REQ_FD = 21,
VHOST_USER_IOTLB_MSG = 22,
VHOST_USER_SET_VRING_ENDIAN = 23,
VHOST_USER_MAX
} VhostUserRequest;
@ -367,8 +369,25 @@ static int vhost_user_set_vring_addr(struct vhost_dev *dev,
static int vhost_user_set_vring_endian(struct vhost_dev *dev,
struct vhost_vring_state *ring)
{
error_report("vhost-user trying to send unhandled ioctl");
return -1;
bool cross_endian = virtio_has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_CROSS_ENDIAN);
VhostUserMsg msg = {
.request = VHOST_USER_SET_VRING_ENDIAN,
.flags = VHOST_USER_VERSION,
.payload.state = *ring,
.size = sizeof(msg.payload.state),
};
if (!cross_endian) {
error_report("vhost-user trying to send unhandled ioctl");
return -1;
}
if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
return -1;
}
return 0;
}
static int vhost_set_vring(struct vhost_dev *dev,