um: drivers: Add virtio vhost-user driver

This module allows virtio devices to be used over a vhost-user socket.

Signed-off-by: Erel Geron <erelx.geron@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index f25b110d4e70..91f23035be08 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -15,6 +15,7 @@
 #include <sys/sysmacros.h>
 #include <sys/un.h>
 #include <sys/types.h>
+#include <sys/eventfd.h>
 #include <os.h>
 
 static void copy_stat(struct uml_stat *dst, const struct stat64 *src)
@@ -620,3 +621,46 @@ int os_falloc_punch(int fd, unsigned long long offset, int len)
         return n;
 }
 
+int os_eventfd(unsigned int initval, int flags)
+{
+        int fd = eventfd(initval, flags);
+
+        if (fd < 0)
+                return -errno;
+        return fd;
+}
+
+int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds,
+                   unsigned int fds_num)
+{
+        struct iovec iov = {
+                .iov_base = (void *) buf,
+                .iov_len = len,
+        };
+        union {
+                char control[CMSG_SPACE(sizeof(*fds) * OS_SENDMSG_MAX_FDS)];
+                struct cmsghdr align;
+        } u;
+        unsigned int fds_size = sizeof(*fds) * fds_num;
+        struct msghdr msg = {
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = u.control,
+                .msg_controllen = CMSG_SPACE(fds_size),
+        };
+        struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+        int err;
+
+        if (fds_num > OS_SENDMSG_MAX_FDS)
+                return -EINVAL;
+        memset(u.control, 0, sizeof(u.control));
+        cmsg->cmsg_level = SOL_SOCKET;
+        cmsg->cmsg_type = SCM_RIGHTS;
+        cmsg->cmsg_len = CMSG_LEN(fds_size);
+        memcpy(CMSG_DATA(cmsg), fds, fds_size);
+        err = sendmsg(fd, &msg, 0);
+
+        if (err < 0)
+                return -errno;
+        return err;
+}