diff options
Diffstat (limited to 'docs/interop/vhost-user.txt')
| -rw-r--r-- | docs/interop/vhost-user.txt | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt index 534caab18a..d51fd58242 100644 --- a/docs/interop/vhost-user.txt +++ b/docs/interop/vhost-user.txt @@ -132,6 +132,16 @@ Depending on the request type, payload can be: Payload: Size bytes array holding the contents of the virtio device's configuration space + * Vring area description + ----------------------- + | u64 | size | offset | + ----------------------- + + u64: a 64-bit integer contains vring index and flags + Size: a 64-bit size of this area + Offset: a 64-bit offset of this area from the start of the + supplied file descriptor + In QEMU the vhost-user message is implemented with the following struct: typedef struct VhostUserMsg { @@ -146,6 +156,7 @@ typedef struct VhostUserMsg { VhostUserLog log; struct vhost_iotlb_msg iotlb; VhostUserConfig config; + VhostUserVringArea area; }; } QEMU_PACKED VhostUserMsg; @@ -367,6 +378,10 @@ The fd is provided via VHOST_USER_SET_SLAVE_REQ_FD ancillary data. A slave may then send VHOST_USER_SLAVE_* messages to the master using this fd communication channel. +If VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD protocol feature is negotiated, +slave can send file descriptors (at most 8 descriptors in each message) +to master via ancillary data using this fd communication channel. + Protocol features ----------------- @@ -380,6 +395,8 @@ Protocol features #define VHOST_USER_PROTOCOL_F_CRYPTO_SESSION 7 #define VHOST_USER_PROTOCOL_F_PAGEFAULT 8 #define VHOST_USER_PROTOCOL_F_CONFIG 9 +#define VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD 10 +#define VHOST_USER_PROTOCOL_F_HOST_NOTIFIER 11 Master message types -------------------- @@ -777,6 +794,27 @@ Slave message types the VHOST_USER_NEED_REPLY flag, master must respond with zero when operation is successfully completed, or non-zero otherwise. + * VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG + + Id: 3 + Equivalent ioctl: N/A + Slave payload: vring area description + Master payload: N/A + + Sets host notifier for a specified queue. The queue index is contained + in the u64 field of the vring area description. The host notifier is + described by the file descriptor (typically it's a VFIO device fd) which + is passed as ancillary data and the size (which is mmap size and should + be the same as host page size) and offset (which is mmap offset) carried + in the vring area description. QEMU can mmap the file descriptor based + on the size and offset to get a memory range. Registering a host notifier + means mapping this memory range to the VM as the specified queue's notify + MMIO region. Slave sends this request to tell QEMU to de-register the + existing notifier if any and register the new notifier if the request is + sent with a file descriptor. + This request should be sent only when VHOST_USER_PROTOCOL_F_HOST_NOTIFIER + protocol feature has been successfully negotiated. + VHOST_USER_PROTOCOL_F_REPLY_ACK: ------------------------------- The original vhost-user specification only demands replies for certain |