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From: Antonios Motakis <a.motakis@virtualopensystems.com>
To: qemu-devel@nongnu.org, snabb-devel@googlegroups.com
Cc: lukego@gmail.com,
	Antonios Motakis <a.motakis@virtualopensystems.com>,
	tech@virtualopensystems.com, n.nikolaev@virtualopensystems.com,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: [Qemu-devel] [PATCH v3 4/7] Add domain socket communication for vhost-user backend
Date: Fri, 13 Dec 2013 12:14:34 +0100	[thread overview]
Message-ID: <1386933277-20003-5-git-send-email-a.motakis@virtualopensystems.com> (raw)
In-Reply-To: <1386933277-20003-1-git-send-email-a.motakis@virtualopensystems.com>

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.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
---
 hw/virtio/vhost-backend.c | 167 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 161 insertions(+), 6 deletions(-)

diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 847809f..96d3bf0 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -14,30 +14,185 @@
 #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 r;
+
+    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 {
+        r = sendmsg(fd, &msgh, 0);
+    } while (r < 0 && errno == EINTR);
+
+    if (r < 0) {
+        fprintf(stderr, "Failed to send msg(%d), reason: %s\n",
+                msg->request, strerror(errno));
+    } else {
+        r = 0;
+    }
+
+    return r;
+}
 
 static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
         void *arg)
 {
+    int fd = dev->control;
+    VhostUserMsg msg;
+    int result = 0, need_reply = 0;
+    int fds[VHOST_MEMORY_MAX_NREGIONS];
+    size_t fd_num = 0;
+
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
-    fprintf(stderr, "vhost_user_call not implemented\n");
 
-    return -1;
+    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 && need_reply) {
+        result = vhost_user_recv(fd, &msg);
+        if (!result) {
+            switch (request) {
+            default:
+                break;
+            }
+        }
+    }
+
+    return result;
 }
 
 static int vhost_user_init(struct vhost_dev *dev, const char *devpath)
 {
+    int fd = -1;
+    struct sockaddr_un un;
+    size_t len;
+
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
-    fprintf(stderr, "vhost_user_init not implemented\n");
 
-    return -1;
+    /* 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;
+    }
+
+    dev->control = fd;
+
+    return fd;
 }
 
 static int vhost_user_cleanup(struct vhost_dev *dev)
 {
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
-    fprintf(stderr, "vhost_user_cleanup not implemented\n");
 
-    return -1;
+    return close(dev->control);
 }
 
 static const VhostOps user_ops = {
-- 
1.8.3.2

  parent reply	other threads:[~2013-12-13 11:15 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-13 11:14 [Qemu-devel] [PATCH v3 0/7] host and vhost-net support for userspace based backends Antonios Motakis
2013-12-13 11:14 ` [Qemu-devel] [PATCH v3 1/7] Add -mem-share option Antonios Motakis
2013-12-14  3:53   ` Eric Blake
2013-12-14 11:09     ` [Qemu-devel] [snabb-devel:650] " Paolo Bonzini
2013-12-16 15:20     ` [Qemu-devel] " Antonios Motakis
2013-12-16 15:47       ` Igor Mammedov
2013-12-17 11:11         ` Paolo Bonzini
2013-12-16  7:32   ` Edgar E. Iglesias
2013-12-16 10:17     ` Paolo Bonzini
2013-12-16 15:21     ` Antonios Motakis
2013-12-17  1:55       ` Edgar E. Iglesias
2013-12-13 11:14 ` [Qemu-devel] [PATCH v3 2/7] Decouple vhost from kernel interface Antonios Motakis
2013-12-13 11:14 ` [Qemu-devel] [PATCH v3 3/7] Add vhost-user skeleton Antonios Motakis
2013-12-13 11:14 ` Antonios Motakis [this message]
2013-12-13 11:14 ` [Qemu-devel] [PATCH v3 5/7] Add vhost-user calls implementation Antonios Motakis
2013-12-16  9:15   ` Luke Gorrie
2013-12-13 11:14 ` [Qemu-devel] [PATCH v3 6/7] Add new vhost-user netdev backend Antonios Motakis
2013-12-13 11:14 ` [Qemu-devel] [PATCH v3 7/7] Add vhost-user reconnection Antonios Motakis
2013-12-16  9:17   ` Luke Gorrie

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