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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
parent08b9e0ba623c4468fe94026a9bdd086526ef62f0 (diff)
downloadqemu-arm-5df04f1762ef78c08fd69e19dcedf3d9ba8c9b86.tar.gz
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>
-rw-r--r--docs/interop/vhost-user.txt16
-rw-r--r--hw/virtio/vhost-user.c23
2 files changed, 37 insertions, 2 deletions
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
index 481ab56e35..954771d0d8 100644
--- a/docs/interop/vhost-user.txt
+++ b/docs/interop/vhost-user.txt
@@ -326,6 +326,7 @@ Protocol features
#define VHOST_USER_PROTOCOL_F_REPLY_ACK 3
#define VHOST_USER_PROTOCOL_F_MTU 4
#define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5
+#define VHOST_USER_PROTOCOL_F_CROSS_ENDIAN 6
Master message types
--------------------
@@ -580,6 +581,21 @@ Master message types
This request should be send only when VIRTIO_F_IOMMU_PLATFORM feature
has been successfully negotiated.
+ * VHOST_USER_SET_VRING_ENDIAN
+
+ Id: 23
+ Equivalent ioctl: VHOST_SET_VRING_ENDIAN
+ Master payload: vring state description
+
+ Set the endianess of a VQ for legacy devices. Little-endian is indicated
+ with state.num set to 0 and big-endian is indicated with state.num set
+ to 1. Other values are invalid.
+ This request should be sent only when VHOST_USER_PROTOCOL_F_CROSS_ENDIAN
+ has been negotiated.
+ Backends that negotiated this feature should handle both endianesses
+ and expect this message once (per VQ) during device configuration
+ (ie. before the master starts the VQ).
+
Slave message types
-------------------
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,