hw/9pfs: Add yield support for preadv coroutine Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

diff --git a/hw/9pfs/cofile.c b/hw/9pfs/cofile.c
index e0d032d..e388146 100644
--- a/hw/9pfs/cofile.c
+++ b/hw/9pfs/cofile.c

@@ -144,3 +144,20 @@
         });
     return err;
 }
+
+int v9fs_co_preadv(V9fsState *s, V9fsFidState *fidp,
+                   struct iovec *iov, int iovcnt, int64_t offset)
+{
+    int fd;
+    int err;
+
+    fd = fidp->fs.fd;
+    v9fs_co_run_in_worker(
+        {
+            err = s->ops->preadv(&s->ctx, fd, iov, iovcnt, offset);
+            if (err < 0) {
+                err = -errno;
+            }
+        });
+    return err;
+}

diff --git a/hw/9pfs/virtio-9p-coth.h b/hw/9pfs/virtio-9p-coth.h
index fa408f8..5fa2972 100644
--- a/hw/9pfs/virtio-9p-coth.h
+++ b/hw/9pfs/virtio-9p-coth.h

@@ -91,4 +91,6 @@
 extern int v9fs_co_link(V9fsState *, V9fsString *, V9fsString *);
 extern int v9fs_co_pwritev(V9fsState *, V9fsFidState *,
                            struct iovec *, int, int64_t);
+extern int v9fs_co_preadv(V9fsState *, V9fsFidState *,
+                          struct iovec *, int, int64_t);
 #endif