vhost: support slave requests channel

Currently, only QEMU sends requests, the backend sends
replies. In some cases, the backend may need to send
requests to QEMU, like IOTLB miss events when IOMMU is
supported.

This patch introduces a new channel for such requests.
QEMU sends a file descriptor of a new socket using
VHOST_USER_SET_SLAVE_REQ_FD.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yliu@fridaylinux.org>

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 474b6e4..2d30f14 100644 (file)
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -207,6 +207,7 @@ vhost_new_device(void)
 
        vhost_devices[i] = dev;
        dev->vid = i;
+       dev->slave_req_fd = -1;
 
        return i;
 }

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 74df747..8405f87 100644 (file)
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -209,6 +209,8 @@ struct virtio_net {
        uint32_t                nr_guest_pages;
        uint32_t                max_guest_pages;
        struct guest_page       *guest_pages;
+
+       int                     slave_req_fd;
 } __rte_cache_aligned;
 
 

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index a068d86..0ba66e1 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -76,6 +76,7 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
        [VHOST_USER_SET_VRING_ENABLE]  = "VHOST_USER_SET_VRING_ENABLE",
        [VHOST_USER_SEND_RARP]  = "VHOST_USER_SEND_RARP",
        [VHOST_USER_NET_SET_MTU]  = "VHOST_USER_NET_SET_MTU",
+       [VHOST_USER_SET_SLAVE_REQ_FD]  = "VHOST_USER_SET_SLAVE_REQ_FD",
 };
 
 static uint64_t
@@ -122,6 +123,11 @@ vhost_backend_cleanup(struct virtio_net *dev)
                munmap((void *)(uintptr_t)dev->log_addr, dev->log_size);
                dev->log_addr = 0;
        }
+
+       if (dev->slave_req_fd >= 0) {
+               close(dev->slave_req_fd);
+               dev->slave_req_fd = -1;
+       }
 }
 
 /*
@@ -886,6 +892,23 @@ vhost_user_net_set_mtu(struct virtio_net *dev, struct VhostUserMsg *msg)
        return 0;
 }
 
+static int
+vhost_user_set_req_fd(struct virtio_net *dev, struct VhostUserMsg *msg)
+{
+       int fd = msg->fds[0];
+
+       if (fd < 0) {
+               RTE_LOG(ERR, VHOST_CONFIG,
+                               "Invalid file descriptor for slave channel (%d)\n",
+                               fd);
+               return -1;
+       }
+
+       dev->slave_req_fd = fd;
+
+       return 0;
+}
+
 /* return bytes# of read on success or negative val on failure. */
 static int
 read_vhost_message(int sockfd, struct VhostUserMsg *msg)
@@ -1113,6 +1136,10 @@ vhost_user_msg_handler(int vid, int fd)
                ret = vhost_user_net_set_mtu(dev, &msg);
                break;
 
+       case VHOST_USER_SET_SLAVE_REQ_FD:
+               ret = vhost_user_set_req_fd(dev, &msg);
+               break;
+
        default:
                ret = -1;
                break;

diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
index 2ba22db..98f6e6f 100644 (file)
--- a/lib/librte_vhost/vhost_user.h
+++ b/lib/librte_vhost/vhost_user.h
@@ -48,12 +48,14 @@
 #define VHOST_USER_PROTOCOL_F_RARP     2
 #define VHOST_USER_PROTOCOL_F_REPLY_ACK        3
 #define VHOST_USER_PROTOCOL_F_NET_MTU 4
+#define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5
 
 #define VHOST_USER_PROTOCOL_FEATURES   ((1ULL << VHOST_USER_PROTOCOL_F_MQ) | \
                                         (1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD) |\
                                         (1ULL << VHOST_USER_PROTOCOL_F_RARP) | \
                                         (1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK) | \
-                                        (1ULL << VHOST_USER_PROTOCOL_F_NET_MTU))
+                                        (1ULL << VHOST_USER_PROTOCOL_F_NET_MTU) | \
+                                        (1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ))
 
 typedef enum VhostUserRequest {
        VHOST_USER_NONE = 0,
@@ -77,9 +79,15 @@ typedef enum VhostUserRequest {
        VHOST_USER_SET_VRING_ENABLE = 18,
        VHOST_USER_SEND_RARP = 19,
        VHOST_USER_NET_SET_MTU = 20,
+       VHOST_USER_SET_SLAVE_REQ_FD = 21,
        VHOST_USER_MAX
 } VhostUserRequest;
 
+typedef enum VhostUserSlaveRequest {
+       VHOST_USER_SLAVE_NONE = 0,
+       VHOST_USER_SLAVE_MAX
+} VhostUserSlaveRequest;
+
 typedef struct VhostUserMemoryRegion {
        uint64_t guest_phys_addr;
        uint64_t memory_size;