From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Date: Mon, 27 Jan 2020 19:00:57 +0000

Subject: [PATCH] virtiofsd: Start wiring up vhost-user

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Listen on our unix socket for the connection from QEMU, when we get it

initialise vhost-user and dive into our own loop variant (currently

dummy).

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry picked from commit f6f3573c6f271af5ded63ce28589a113f7205c72)

---

 tools/virtiofsd/fuse_i.h         |  4 ++

 tools/virtiofsd/fuse_lowlevel.c  |  5 ++

 tools/virtiofsd/fuse_lowlevel.h  |  7 +++

 tools/virtiofsd/fuse_virtio.c    | 87 +++++++++++++++++++++++++++++++-

 tools/virtiofsd/fuse_virtio.h    |  2 +

 tools/virtiofsd/passthrough_ll.c |  7 +--

 6 files changed, 106 insertions(+), 6 deletions(-)

diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h

index 82d6ac7115..ec04449069 100644

--- a/tools/virtiofsd/fuse_i.h

+++ b/tools/virtiofsd/fuse_i.h

@@ -13,6 +13,8 @@

 #include "fuse.h"

 #include "fuse_lowlevel.h"

+struct fv_VuDev;

+

 struct fuse_req {

     struct fuse_session *se;

     uint64_t unique;

@@ -65,6 +67,8 @@ struct fuse_session {

     size_t bufsize;

     int error;

     char *vu_socket_path;

+    int   vu_socketfd;

+    struct fv_VuDev *virtio_dev;

 };

 struct fuse_chan {

diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c

index 5df124e64b..af09fa2b94 100644

--- a/tools/virtiofsd/fuse_lowlevel.c

+++ b/tools/virtiofsd/fuse_lowlevel.c

@@ -2242,6 +2242,11 @@ void fuse_session_unmount(struct fuse_session *se)

 {

 }

+int fuse_lowlevel_is_virtio(struct fuse_session *se)

+{

+    return se->vu_socket_path != NULL;

+}

+

 #ifdef linux

 int fuse_req_getgroups(fuse_req_t req, int size, gid_t list[])

 {

diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h

index 2fa225d40b..f6b34700af 100644

--- a/tools/virtiofsd/fuse_lowlevel.h

+++ b/tools/virtiofsd/fuse_lowlevel.h

@@ -1755,6 +1755,13 @@ void fuse_req_interrupt_func(fuse_req_t req, fuse_interrupt_func_t func,

  */

 int fuse_req_interrupted(fuse_req_t req);

+/**

+ * Check if the session is connected via virtio

+ *

+ * @param se session object

+ * @return 1 if the session is a virtio session

+ */

+int fuse_lowlevel_is_virtio(struct fuse_session *se);

 /*

  * Inquiry functions

diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c

index cbef6ffdda..2ae3c764dd 100644

--- a/tools/virtiofsd/fuse_virtio.c

+++ b/tools/virtiofsd/fuse_virtio.c

@@ -19,18 +19,78 @@

 #include <stdint.h>

 #include <stdio.h>

+#include <stdlib.h>

 #include <string.h>

 #include <sys/socket.h>

 #include <sys/types.h>

 #include <sys/un.h>

 #include <unistd.h>

+#include "contrib/libvhost-user/libvhost-user.h"

+

+/*

+ * We pass the dev element into libvhost-user

+ * and then use it to get back to the outer

+ * container for other data.

+ */

+struct fv_VuDev {

+    VuDev dev;

+    struct fuse_session *se;

+};

+

 /* From spec */

 struct virtio_fs_config {

     char tag[36];

     uint32_t num_queues;

 };

+/*

+ * Callback from libvhost-user if there's a new fd we're supposed to listen

+ * to, typically a queue kick?

+ */

+static void fv_set_watch(VuDev *dev, int fd, int condition, vu_watch_cb cb,

+                         void *data)

+{

+    fuse_log(FUSE_LOG_WARNING, "%s: TODO! fd=%d\n", __func__, fd);

+}

+

+/*

+ * Callback from libvhost-user if we're no longer supposed to listen on an fd

+ */

+static void fv_remove_watch(VuDev *dev, int fd)

+{

+    fuse_log(FUSE_LOG_WARNING, "%s: TODO! fd=%d\n", __func__, fd);

+}

+

+/* Callback from libvhost-user to panic */

+static void fv_panic(VuDev *dev, const char *err)

+{

+    fuse_log(FUSE_LOG_ERR, "%s: libvhost-user: %s\n", __func__, err);

+    /* TODO: Allow reconnects?? */

+    exit(EXIT_FAILURE);

+}

+

+static bool fv_queue_order(VuDev *dev, int qidx)

+{

+    return false;

+}

+

+static const VuDevIface fv_iface = {

+    /* TODO: Add other callbacks */

+    .queue_is_processed_in_order = fv_queue_order,

+};

+

+int virtio_loop(struct fuse_session *se)

+{

+    fuse_log(FUSE_LOG_INFO, "%s: Entry\n", __func__);

+

+    while (1) {

+        /* TODO: Add stuffing */

+    }

+

+    fuse_log(FUSE_LOG_INFO, "%s: Exit\n", __func__);

+}

+

 int virtio_session_mount(struct fuse_session *se)

 {

     struct sockaddr_un un;

@@ -75,5 +135,30 @@ int virtio_session_mount(struct fuse_session *se)

         return -1;

     }

-    return -1;

+    fuse_log(FUSE_LOG_INFO, "%s: Waiting for vhost-user socket connection...\n",

+             __func__);

+    int data_sock = accept(listen_sock, NULL, NULL);

+    if (data_sock == -1) {

+        fuse_log(FUSE_LOG_ERR, "vhost socket accept: %m\n");

+        close(listen_sock);

+        return -1;

+    }

+    close(listen_sock);

+    fuse_log(FUSE_LOG_INFO, "%s: Received vhost-user socket connection\n",

+             __func__);

+

+    /* TODO: Some cleanup/deallocation! */

+    se->virtio_dev = calloc(sizeof(struct fv_VuDev), 1);

+    if (!se->virtio_dev) {

+        fuse_log(FUSE_LOG_ERR, "%s: virtio_dev calloc failed\n", __func__);

+        close(data_sock);

+        return -1;

+    }

+

+    se->vu_socketfd = data_sock;

+    se->virtio_dev->se = se;

+    vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, fv_set_watch,

+            fv_remove_watch, &fv_iface);

+

+    return 0;

 }

diff --git a/tools/virtiofsd/fuse_virtio.h b/tools/virtiofsd/fuse_virtio.h

index 8f2edb69ca..23026d6e4c 100644

--- a/tools/virtiofsd/fuse_virtio.h

+++ b/tools/virtiofsd/fuse_virtio.h

@@ -20,4 +20,6 @@ struct fuse_session;

 int virtio_session_mount(struct fuse_session *se);

+int virtio_loop(struct fuse_session *se);

+

 #endif

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c

index fc9b264d56..037c5d7b26 100644

--- a/tools/virtiofsd/passthrough_ll.c

+++ b/tools/virtiofsd/passthrough_ll.c

@@ -36,6 +36,7 @@

  */

 #include "qemu/osdep.h"

+#include "fuse_virtio.h"

 #include "fuse_lowlevel.h"

 #include <assert.h>

 #include <dirent.h>

@@ -1395,11 +1396,7 @@ int main(int argc, char *argv[])

     fuse_daemonize(opts.foreground);

     /* Block until ctrl+c or fusermount -u */

-    if (opts.singlethread) {

-        ret = fuse_session_loop(se);

-    } else {

-        ret = fuse_session_loop_mt(se, opts.clone_fd);

-    }

+    ret = virtio_loop(se);

     fuse_session_unmount(se);

 err_out3: