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vhost-user: Add MTU protocol feature and op

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This patch implements VHOST_USER_PROTOCOL_F_NET_MTU
protocol feature and VHOST_USER_NET_SET_MTU request so
that the backend gets notified of the user defined host
MTU.

If backend supports VHOST_USER_PROTOCOL_F_REPLY_ACK,
QEMU assumes MTU is valid if success is returned.

Vhost-net driver sends this request through a new
vhost_net_set_mtu vhost_ops entry.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Aaron Conole <aconole@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Maxime Coquelin 2016-12-10 16:30:36 +01:00 committed by Michael S. Tsirkin
parent 283e2c2adc
commit c5f048d8fb
3 changed files with 52 additions and 0 deletions
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16
docs/specs/vhost-user.txt
View File

@ -259,6 +259,7 @@ Protocol features
#define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1
#define VHOST_USER_PROTOCOL_F_RARP 2
#define VHOST_USER_PROTOCOL_F_REPLY_ACK 3
#define VHOST_USER_PROTOCOL_F_MTU 4
Message types
-------------
@ -470,6 +471,21 @@ Message types
The first 6 bytes of the payload contain the mac address of the guest to
allow the vhost user backend to construct and broadcast the fake RARP.
* VHOST_USER_NET_SET_MTU
Id: 20
Equivalent ioctl: N/A
Master payload: u64
Set host MTU value exposed to the guest.
This request should be sent only when VIRTIO_NET_F_MTU feature has been
successfully negotiated, VHOST_USER_F_PROTOCOL_FEATURES is present in
VHOST_USER_GET_FEATURES and protocol feature bit
VHOST_USER_PROTOCOL_F_NET_MTU is present in
VHOST_USER_GET_PROTOCOL_FEATURES.
If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, slave must respond
with zero in case the specified MTU is valid, or non-zero otherwise.
VHOST_USER_PROTOCOL_F_REPLY_ACK:
-------------------------------
The original vhost-user specification only demands replies for certain

34
hw/virtio/vhost-user.c
View File

@ -32,6 +32,7 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
VHOST_USER_PROTOCOL_F_RARP = 2,
VHOST_USER_PROTOCOL_F_REPLY_ACK = 3,
VHOST_USER_PROTOCOL_F_NET_MTU = 4,
VHOST_USER_PROTOCOL_F_MAX
};
@ -59,6 +60,7 @@ typedef enum VhostUserRequest {
VHOST_USER_GET_QUEUE_NUM = 17,
VHOST_USER_SET_VRING_ENABLE = 18,
VHOST_USER_SEND_RARP = 19,
VHOST_USER_NET_SET_MTU = 20,
VHOST_USER_MAX
} VhostUserRequest;
@ -186,6 +188,7 @@ static bool vhost_user_one_time_request(VhostUserRequest request)
case VHOST_USER_RESET_OWNER:
case VHOST_USER_SET_MEM_TABLE:
case VHOST_USER_GET_QUEUE_NUM:
case VHOST_USER_NET_SET_MTU:
return true;
default:
return false;
@ -685,6 +688,36 @@ static bool vhost_user_can_merge(struct vhost_dev *dev,
return mfd == rfd;
}
static int vhost_user_net_set_mtu(struct vhost_dev *dev, uint16_t mtu)
{
VhostUserMsg msg;
bool reply_supported = virtio_has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_REPLY_ACK);
if (!(dev->protocol_features & (1ULL << VHOST_USER_PROTOCOL_F_NET_MTU))) {
return 0;
}
msg.request = VHOST_USER_NET_SET_MTU;
msg.payload.u64 = mtu;
msg.size = sizeof(msg.payload.u64);
msg.flags = VHOST_USER_VERSION;
if (reply_supported) {
msg.flags |= VHOST_USER_NEED_REPLY_MASK;
}
if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
return -1;
}
/* If reply_ack supported, slave has to ack specified MTU is valid */
if (reply_supported) {
return process_message_reply(dev, msg.request);
}
return 0;
}
const VhostOps user_ops = {
.backend_type = VHOST_BACKEND_TYPE_USER,
.vhost_backend_init = vhost_user_init,
@ -708,4 +741,5 @@ const VhostOps user_ops = {
.vhost_requires_shm_log = vhost_user_requires_shm_log,
.vhost_migration_done = vhost_user_migration_done,
.vhost_backend_can_merge = vhost_user_can_merge,
.vhost_net_set_mtu = vhost_user_net_set_mtu,
};

2
include/hw/virtio/vhost-backend.h
View File

@ -32,6 +32,7 @@ typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
struct vhost_vring_file *file);
typedef int (*vhost_net_set_mtu_op)(struct vhost_dev *dev, uint16_t mtu);
typedef int (*vhost_scsi_set_endpoint_op)(struct vhost_dev *dev,
struct vhost_scsi_target *target);
typedef int (*vhost_scsi_clear_endpoint_op)(struct vhost_dev *dev,
@ -83,6 +84,7 @@ typedef struct VhostOps {
vhost_backend_cleanup vhost_backend_cleanup;
vhost_backend_memslots_limit vhost_backend_memslots_limit;
vhost_net_set_backend_op vhost_net_set_backend;
vhost_net_set_mtu_op vhost_net_set_mtu;
vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint;
vhost_scsi_clear_endpoint_op vhost_scsi_clear_endpoint;
vhost_scsi_get_abi_version_op vhost_scsi_get_abi_version;