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| author | Felipe Franciosi <felipe@nutanix.com> | 2017-06-14 18:44:38 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2017-08-02 00:13:25 +0300 |
| commit | 5df04f1762ef78c08fd69e19dcedf3d9ba8c9b86 (patch) | |
| tree | eeb55bb6c1f81c111cdf0d521fc91adb1daf4887 /docs | |
| parent | 08b9e0ba623c4468fe94026a9bdd086526ef62f0 (diff) | |
| download | qemu-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>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/interop/vhost-user.txt | 16 |
1 files changed, 16 insertions, 0 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 ------------------- |