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authorFelipe Franciosi <felipe@nutanix.com>2017-06-14 18:44:38 +0100
committerMichael S. Tsirkin <mst@redhat.com>2017-08-02 00:13:25 +0300
commit5df04f1762ef78c08fd69e19dcedf3d9ba8c9b86 (patch)
treeeeb55bb6c1f81c111cdf0d521fc91adb1daf4887 /hw/virtio/vhost-user.c
parent08b9e0ba623c4468fe94026a9bdd086526ef62f0 (diff)
downloadfocaccia-qemu-5df04f1762ef78c08fd69e19dcedf3d9ba8c9b86.tar.gz
focaccia-qemu-5df04f1762ef78c08fd69e19dcedf3d9ba8c9b86.zip
vhost-user: fix legacy cross-endian configurations
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>
Diffstat (limited to 'hw/virtio/vhost-user.c')
-rw-r--r--hw/virtio/vhost-user.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 2203011125..093675ed98 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -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,