Add structures for passing vhost-user messages over a unix domain socket.
This is the equivalent of the existing vhost-kernel ioctls.
Connect to the named unix domain socket. The system call sendmsg
is used for communication. To be able to pass file descriptors
between processes - we use SCM_RIGHTS type in the message control header.
Signed-off-by: Antonios Motakis <a.mota...@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com>
---
hw/virtio/vhost-backend.c | 164 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 162 insertions(+), 2 deletions(-)
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 80defe4..264a0a1 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -15,6 +15,115 @@
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <linux/vhost.h>
+
+#define VHOST_MEMORY_MAX_NREGIONS 8
+
+typedef enum VhostUserRequest {
+ VHOST_USER_NONE = 0,
+ VHOST_USER_GET_FEATURES = 1,
+ VHOST_USER_SET_FEATURES = 2,
+ VHOST_USER_SET_OWNER = 3,
+ VHOST_USER_RESET_OWNER = 4,
+ VHOST_USER_SET_MEM_TABLE = 5,
+ VHOST_USER_SET_LOG_BASE = 6,
+ VHOST_USER_SET_LOG_FD = 7,
+ VHOST_USER_SET_VRING_NUM = 8,
+ VHOST_USER_SET_VRING_ADDR = 9,
+ VHOST_USER_SET_VRING_BASE = 10,
+ VHOST_USER_GET_VRING_BASE = 11,
+ VHOST_USER_SET_VRING_KICK = 12,
+ VHOST_USER_SET_VRING_CALL = 13,
+ VHOST_USER_SET_VRING_ERR = 14,
+ VHOST_USER_NET_SET_BACKEND = 15,
+ VHOST_USER_MAX
+} VhostUserRequest;
+
+typedef struct VhostUserMemoryRegion {
+ __u64 guest_phys_addr;
+ __u64 memory_size;
+ __u64 userspace_addr;
+} VhostUserMemoryRegion;
+
+typedef struct VhostUserMemory {
+ __u32 nregions;
+ VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
+} VhostUserMemory;
+
+typedef struct VhostUserMsg {
+ VhostUserRequest request;
+
+ int flags;
+ union {
+ uint64_t u64;
+ int fd;
+ struct vhost_vring_state state;
+ struct vhost_vring_addr addr;
+ struct vhost_vring_file file;
+
+ VhostUserMemory memory;
+ };
+} VhostUserMsg;
+
+static int vhost_user_recv(int fd, VhostUserMsg *msg)
+{
+ ssize_t r = read(fd, msg, sizeof(VhostUserMsg));
+
+ return (r == sizeof(VhostUserMsg)) ? 0 : -1;
+}
+
+static int vhost_user_send_fds(int fd, const VhostUserMsg *msg, int *fds,
+ size_t fd_num)
+{
+ int ret;
+
+ struct msghdr msgh;
+ struct iovec iov[1];
+
+ size_t fd_size = fd_num * sizeof(int);
+ char control[CMSG_SPACE(fd_size)];
+ struct cmsghdr *cmsg;
+
+ memset(&msgh, 0, sizeof(msgh));
+ memset(control, 0, sizeof(control));
+
+ /* set the payload */
+ iov[0].iov_base = (void *) msg;
+ iov[0].iov_len = sizeof(VhostUserMsg);
+
+ msgh.msg_iov = iov;
+ msgh.msg_iovlen = 1;
+
+ if (fd_num) {
+ msgh.msg_control = control;
+ msgh.msg_controllen = sizeof(control);
+
+ cmsg = CMSG_FIRSTHDR(&msgh);
+
+ cmsg->cmsg_len = CMSG_LEN(fd_size);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ memcpy(CMSG_DATA(cmsg), fds, fd_size);
+ } else {
+ msgh.msg_control = 0;
+ msgh.msg_controllen = 0;
+ }
+
+ do {
+ ret = sendmsg(fd, &msgh, 0);
+ } while (ret < 0 && errno == EINTR);
+
+ if (ret < 0) {
+ fprintf(stderr, "Failed to send msg(%d), reason: %s\n",
+ msg->request, strerror(errno));
+ } else {
+ ret = 0;
+ }
+
+ return ret;
+}
static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
void *arg)
@@ -23,6 +132,39 @@ static int vhost_kernel_call(struct vhost_dev *dev,
unsigned long int request,
return ioctl(fd, request, arg);
}
+static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
+ void *arg)
+{
+ int fd = dev->control;
+ VhostUserMsg msg;
+ int result = 0;
+ int fds[VHOST_MEMORY_MAX_NREGIONS];
+ size_t fd_num = 0;
+
+ memset(&msg, 0, sizeof(VhostUserMsg));
+
+ switch (request) {
+ default:
+ fprintf(stderr, "vhost-user trying to send unhandled ioctl\n");
+ return -1;
+ break;
+ }
+
+ result = vhost_user_send_fds(fd, &msg, fds, fd_num);
+
+ if (!result) {
+ result = vhost_user_recv(fd, &msg);
+ if (!result) {
+ switch (request) {
+ default:
+ fprintf(stderr, "vhost-user received unhandled message\n");
+ }
+ }
+ }
+
+ return result;
+}
+
int vhost_call(struct vhost_dev *dev, unsigned long int request, void *arg)
{
int result = -1;
@@ -32,7 +174,7 @@ int vhost_call(struct vhost_dev *dev, unsigned long int
request, void *arg)
result = vhost_kernel_call(dev, request, arg);
break;
case VHOST_BACKEND_TYPE_USER:
- fprintf(stderr, "vhost-user not implemented\n");
+ result = vhost_user_call(dev, request, arg);
break;
default:
fprintf(stderr, "Unknown vhost backend type\n");
@@ -44,13 +186,31 @@ int vhost_call(struct vhost_dev *dev, unsigned long int
request, void *arg)
int vhost_backend_init(struct vhost_dev *dev, const char *devpath)
{
int fd = -1;
+ struct sockaddr_un un;
+ size_t len;
switch (dev->backend_type) {
case VHOST_BACKEND_TYPE_KERNEL:
fd = open(devpath, O_RDWR);
break;
case VHOST_BACKEND_TYPE_USER:
- fprintf(stderr, "vhost-user not implemented\n");
+ /* Create the socket */
+ fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (fd == -1) {
+ perror("socket");
+ return -1;
+ }
+
+ un.sun_family = AF_UNIX;
+ strcpy(un.sun_path, devpath);
+
+ len = sizeof(un.sun_family) + strlen(devpath);
+
+ /* Connect */
+ if (connect(fd, (struct sockaddr *) &un, len) == -1) {
+ perror("connect");
+ return -1;
+ }
break;
default:
fprintf(stderr, "Unknown vhost backend type\n");
--
1.8.3.2
