[Qemu-devel] [PATCH v4 0/3] Add vhost-user-input

[Qemu-devel] [PATCH v4 0/3] Add vhost-user-input

[Marc-André Lureau]

Hi,

v4:
- update "libvhost-user: fix -Werror=format= on ppc64"

v3:
- rebased, fixing some warnings found during merge

v2:
- build fixes

v1: (changes since original v6 series)
- add "libvhost-user: fix -Waddress-of-packed-member" & "util: simplify unix_listen()"
- use unix_listen()
- build vhost-user-input by default (when applicable)

Marc-André Lureau (3):
  libvhost-user: fix cast warnings on 32 bits
  libvhost-user: fix -Werror=format= on ppc64
  contrib: add vhost-user-input

 contrib/libvhost-user/libvhost-user.c  |  12 +-
 contrib/vhost-user-input/main.c        | 393 +++++++++++++++++++++++++
 MAINTAINERS                            |   1 +
 Makefile                               |  11 +
 Makefile.objs                          |   1 +
 contrib/vhost-user-input/Makefile.objs |   1 +
 6 files changed, 414 insertions(+), 5 deletions(-)
 create mode 100644 contrib/vhost-user-input/main.c
 create mode 100644 contrib/vhost-user-input/Makefile.objs

-- 
2.21.0.777.g83232e3864

[Qemu-devel] [PATCH v4 1/3] libvhost-user: fix cast warnings on 32 bits

[Marc-André Lureau]

Fixes warnings:
 warning: cast to pointer from integer of different size
 [-Wint-to-pointer-cast]

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 contrib/libvhost-user/libvhost-user.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index 74d42177c5..40443a3daa 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -621,7 +621,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
          * data that's already arrived in the shared process.
          * TODO: How to do hugepage
          */
-        ret = madvise((void *)dev_region->mmap_addr,
+        ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
                       dev_region->size + dev_region->mmap_offset,
                       MADV_DONTNEED);
         if (ret) {
@@ -633,7 +633,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
          * in neighbouring pages.
          * TODO: Turn this backon later.
          */
-        ret = madvise((void *)dev_region->mmap_addr,
+        ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
                       dev_region->size + dev_region->mmap_offset,
                       MADV_NOHUGEPAGE);
         if (ret) {
@@ -666,7 +666,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
         DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
                 __func__, i, reg_struct.range.start, reg_struct.range.len);
         /* Now it's registered we can let the client at it */
-        if (mprotect((void *)dev_region->mmap_addr,
+        if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
                      dev_region->size + dev_region->mmap_offset,
                      PROT_READ | PROT_WRITE)) {
             vu_panic(dev, "failed to mprotect region %d for postcopy (%s)",
-- 
2.21.0.777.g83232e3864

Re: [Qemu-devel] [PATCH v4 1/3] libvhost-user: fix cast warnings on 32 bits

[Philippe Mathieu-Daudé]

On 5/14/19 12:41 PM, Marc-André Lureau wrote:
> Fixes warnings:
>  warning: cast to pointer from integer of different size
>  [-Wint-to-pointer-cast]
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  contrib/libvhost-user/libvhost-user.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
> index 74d42177c5..40443a3daa 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -621,7 +621,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
>           * data that's already arrived in the shared process.
>           * TODO: How to do hugepage
>           */
> -        ret = madvise((void *)dev_region->mmap_addr,
> +        ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
>                        dev_region->size + dev_region->mmap_offset,
>                        MADV_DONTNEED);
>          if (ret) {
> @@ -633,7 +633,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
>           * in neighbouring pages.
>           * TODO: Turn this backon later.
>           */
> -        ret = madvise((void *)dev_region->mmap_addr,
> +        ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
>                        dev_region->size + dev_region->mmap_offset,
>                        MADV_NOHUGEPAGE);
>          if (ret) {
> @@ -666,7 +666,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
>          DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
>                  __func__, i, reg_struct.range.start, reg_struct.range.len);
>          /* Now it's registered we can let the client at it */
> -        if (mprotect((void *)dev_region->mmap_addr,
> +        if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
>                       dev_region->size + dev_region->mmap_offset,
>                       PROT_READ | PROT_WRITE)) {
>              vu_panic(dev, "failed to mprotect region %d for postcopy (%s)",
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

[Qemu-devel] [PATCH v4 2/3] libvhost-user: fix -Werror=format= on ppc64

[Marc-André Lureau]

That should fix the following warning:

/home/pm215/qemu/contrib/libvhost-user/libvhost-user.c: In function
‘vu_set_mem_table_exec_postcopy’:
/home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
format ‘%llx’ expects argument of type ‘long long unsigned int’, but
argument 5 has type ‘__u64’ [-Werror=format=]
         DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
         ^
/home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
format ‘%llx’ expects argument of type ‘long long unsigned int’, but
argument 6 has type ‘__u64’ [-Werror=format=]
cc1: all warnings being treated as errors

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 contrib/libvhost-user/libvhost-user.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index 40443a3daa..ab85166b15 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -663,8 +663,10 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
                      __func__, i);
             return false;
         }
-        DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
-                __func__, i, reg_struct.range.start, reg_struct.range.len);
+        DPRINT("%s: region %d: Registered userfault for %"
+               PRIu64 " + %" PRIu64 "\n", __func__, i,
+               (uint64_t)reg_struct.range.start,
+               (uint64_t)reg_struct.range.len);
         /* Now it's registered we can let the client at it */
         if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
                      dev_region->size + dev_region->mmap_offset,
-- 
2.21.0.777.g83232e3864

Re: [Qemu-devel] [PATCH v4 2/3] libvhost-user: fix -Werror=format= on ppc64

[Philippe Mathieu-Daudé]

Hi Marc-André,

On 5/14/19 12:41 PM, Marc-André Lureau wrote:
> That should fix the following warning:
> 
> /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c: In function
> ‘vu_set_mem_table_exec_postcopy’:
> /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> argument 5 has type ‘__u64’ [-Werror=format=]
>          DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
>          ^
> /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> argument 6 has type ‘__u64’ [-Werror=format=]
> cc1: all warnings being treated as errors
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  contrib/libvhost-user/libvhost-user.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
> index 40443a3daa..ab85166b15 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -663,8 +663,10 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
>                       __func__, i);
>              return false;
>          }
> -        DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> -                __func__, i, reg_struct.range.start, reg_struct.range.len);
> +        DPRINT("%s: region %d: Registered userfault for %"
> +               PRIu64 " + %" PRIu64 "\n", __func__, i,

I guess you want PRIx64 in both places here.

I'd put the '%' on the next line:

           DPRINT("%s: region %d: Registered userfault for "
                  "%" PRIx64 " + %" PRIx64 "\n", __func__, i,

Using PRIx64:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +               (uint64_t)reg_struct.range.start,
> +               (uint64_t)reg_struct.range.len);
>          /* Now it's registered we can let the client at it */
>          if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
>                       dev_region->size + dev_region->mmap_offset,
> 

Re: [Qemu-devel] [PATCH v4 2/3] libvhost-user: fix -Werror=format= on ppc64

[Marc-André Lureau]

Hi

On Tue, May 14, 2019 at 2:10 PM Philippe Mathieu-Daudé
<philmd@redhat.com> wrote:
>
> Hi Marc-André,
>
> On 5/14/19 12:41 PM, Marc-André Lureau wrote:
> > That should fix the following warning:
> >
> > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c: In function
> > ‘vu_set_mem_table_exec_postcopy’:
> > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> > format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> > argument 5 has type ‘__u64’ [-Werror=format=]
> >          DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> >          ^
> > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> > format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> > argument 6 has type ‘__u64’ [-Werror=format=]
> > cc1: all warnings being treated as errors
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  contrib/libvhost-user/libvhost-user.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
> > index 40443a3daa..ab85166b15 100644
> > --- a/contrib/libvhost-user/libvhost-user.c
> > +++ b/contrib/libvhost-user/libvhost-user.c
> > @@ -663,8 +663,10 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
> >                       __func__, i);
> >              return false;
> >          }
> > -        DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> > -                __func__, i, reg_struct.range.start, reg_struct.range.len);
> > +        DPRINT("%s: region %d: Registered userfault for %"
> > +               PRIu64 " + %" PRIu64 "\n", __func__, i,
>
> I guess you want PRIx64 in both places here.
>
> I'd put the '%' on the next line:
>
>            DPRINT("%s: region %d: Registered userfault for "
>                   "%" PRIx64 " + %" PRIx64 "\n", __func__, i,
>
> Using PRIx64:
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

indeed, thanks
Gerd, can you change it on commit?

-- 
Marc-André Lureau

Re: [Qemu-devel] [PATCH v4 2/3] libvhost-user: fix -Werror=format= on ppc64

[Gerd Hoffmann]

On Tue, May 14, 2019 at 02:33:41PM +0200, Marc-André Lureau wrote:
> Hi
> 
> On Tue, May 14, 2019 at 2:10 PM Philippe Mathieu-Daudé
> <philmd@redhat.com> wrote:
> >
> > Hi Marc-André,
> >
> > On 5/14/19 12:41 PM, Marc-André Lureau wrote:
> > > That should fix the following warning:
> > >
> > > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c: In function
> > > ‘vu_set_mem_table_exec_postcopy’:
> > > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> > > format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> > > argument 5 has type ‘__u64’ [-Werror=format=]
> > >          DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> > >          ^
> > > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> > > format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> > > argument 6 has type ‘__u64’ [-Werror=format=]
> > > cc1: all warnings being treated as errors
> > >
> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > > ---
> > >  contrib/libvhost-user/libvhost-user.c | 6 ++++--
> > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
> > > index 40443a3daa..ab85166b15 100644
> > > --- a/contrib/libvhost-user/libvhost-user.c
> > > +++ b/contrib/libvhost-user/libvhost-user.c
> > > @@ -663,8 +663,10 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
> > >                       __func__, i);
> > >              return false;
> > >          }
> > > -        DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> > > -                __func__, i, reg_struct.range.start, reg_struct.range.len);
> > > +        DPRINT("%s: region %d: Registered userfault for %"
> > > +               PRIu64 " + %" PRIu64 "\n", __func__, i,
> >
> > I guess you want PRIx64 in both places here.
> >
> > I'd put the '%' on the next line:
> >
> >            DPRINT("%s: region %d: Registered userfault for "
> >                   "%" PRIx64 " + %" PRIx64 "\n", __func__, i,
> >
> > Using PRIx64:
> > Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> indeed, thanks
> Gerd, can you change it on commit?

Fixed & queued.

What is the status of the vhost-gpu series btw?
It doesn't apply cleanly (simliar to v3 of this series),
IIRC I've mentioned that a while back ...

cheers,
  Gerd

Re: [Qemu-devel] [PATCH v4 2/3] libvhost-user: fix -Werror=format= on ppc64

[Marc-André Lureau]

Hi

On Wed, May 22, 2019 at 7:23 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> On Tue, May 14, 2019 at 02:33:41PM +0200, Marc-André Lureau wrote:
> > Hi
> >
> > On Tue, May 14, 2019 at 2:10 PM Philippe Mathieu-Daudé
> > <philmd@redhat.com> wrote:
> > >
> > > Hi Marc-André,
> > >
> > > On 5/14/19 12:41 PM, Marc-André Lureau wrote:
> > > > That should fix the following warning:
> > > >
> > > > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c: In function
> > > > ‘vu_set_mem_table_exec_postcopy’:
> > > > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> > > > format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> > > > argument 5 has type ‘__u64’ [-Werror=format=]
> > > >          DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> > > >          ^
> > > > /home/pm215/qemu/contrib/libvhost-user/libvhost-user.c:666:9: error:
> > > > format ‘%llx’ expects argument of type ‘long long unsigned int’, but
> > > > argument 6 has type ‘__u64’ [-Werror=format=]
> > > > cc1: all warnings being treated as errors
> > > >
> > > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > > > ---
> > > >  contrib/libvhost-user/libvhost-user.c | 6 ++++--
> > > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
> > > > index 40443a3daa..ab85166b15 100644
> > > > --- a/contrib/libvhost-user/libvhost-user.c
> > > > +++ b/contrib/libvhost-user/libvhost-user.c
> > > > @@ -663,8 +663,10 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
> > > >                       __func__, i);
> > > >              return false;
> > > >          }
> > > > -        DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> > > > -                __func__, i, reg_struct.range.start, reg_struct.range.len);
> > > > +        DPRINT("%s: region %d: Registered userfault for %"
> > > > +               PRIu64 " + %" PRIu64 "\n", __func__, i,
> > >
> > > I guess you want PRIx64 in both places here.
> > >
> > > I'd put the '%' on the next line:
> > >
> > >            DPRINT("%s: region %d: Registered userfault for "
> > >                   "%" PRIx64 " + %" PRIx64 "\n", __func__, i,
> > >
> > > Using PRIx64:
> > > Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> >
> > indeed, thanks
> > Gerd, can you change it on commit?
>
> Fixed & queued.
>
> What is the status of the vhost-gpu series btw?
> It doesn't apply cleanly (simliar to v3 of this series),
> IIRC I've mentioned that a while back ...

I thought I replied to you. It is strange, because the last series I
sent did apply succesfully in patchew:
https://patchew.org/QEMU/20190513184433.21038-1-marcandre.lureau@redhat.com/

It didn't change much since then, I updated the doc to mention the
pixman format of bitmaps, and fixed some conflicts on rebase:
https://github.com/elmarco/qemu/tree/vhost-user-gpu

I'll resend once the input series is merged, unless you have more
comments to make on v7.

thanks!

-- 
Marc-André Lureau

[Qemu-devel] [PATCH v4 3/3] contrib: add vhost-user-input

[Marc-André Lureau]

Add a vhost-user input backend example, based on virtio-input-host
device. It takes an evdev path as argument, and can be associated with
a vhost-user-input device via a UNIX socket:

$ vhost-user-input -p /dev/input/eventX -s /tmp/vui.sock

$ qemu ... -chardev socket,id=vuic,path=/tmp/vui.sock
  -device vhost-user-input-pci,chardev=vuic

This example is intentionally not included in $TOOLS, and not
installed by default.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 contrib/vhost-user-input/main.c        | 393 +++++++++++++++++++++++++
 MAINTAINERS                            |   1 +
 Makefile                               |  11 +
 Makefile.objs                          |   1 +
 contrib/vhost-user-input/Makefile.objs |   1 +
 5 files changed, 407 insertions(+)
 create mode 100644 contrib/vhost-user-input/main.c
 create mode 100644 contrib/vhost-user-input/Makefile.objs

diff --git a/contrib/vhost-user-input/main.c b/contrib/vhost-user-input/main.c
new file mode 100644
index 0000000000..8d493f598e
--- /dev/null
+++ b/contrib/vhost-user-input/main.c
@@ -0,0 +1,393 @@
+/*
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+#include <glib.h>
+#include <linux/input.h>
+
+#include "qemu/iov.h"
+#include "qemu/bswap.h"
+#include "qemu/sockets.h"
+#include "contrib/libvhost-user/libvhost-user.h"
+#include "contrib/libvhost-user/libvhost-user-glib.h"
+#include "standard-headers/linux/virtio_input.h"
+#include "qapi/error.h"
+
+typedef struct virtio_input_event virtio_input_event;
+typedef struct virtio_input_config virtio_input_config;
+
+typedef struct VuInput {
+    VugDev dev;
+    GSource *evsrc;
+    int evdevfd;
+    GArray *config;
+    virtio_input_config *sel_config;
+    struct {
+        virtio_input_event event;
+        VuVirtqElement *elem;
+    } *queue;
+    uint32_t qindex, qsize;
+} VuInput;
+
+static void vi_input_send(VuInput *vi, struct virtio_input_event *event)
+{
+    VuDev *dev = &vi->dev.parent;
+    VuVirtq *vq = vu_get_queue(dev, 0);
+    VuVirtqElement *elem;
+    int i, len;
+
+    /* queue up events ... */
+    if (vi->qindex == vi->qsize) {
+        vi->qsize++;
+        vi->queue = g_realloc_n(vi->queue, vi->qsize, sizeof(vi->queue[0]));
+    }
+    vi->queue[vi->qindex++].event = *event;
+
+    /* ... until we see a report sync ... */
+    if (event->type != htole16(EV_SYN) ||
+        event->code != htole16(SYN_REPORT)) {
+        return;
+    }
+
+    /* ... then check available space ... */
+    for (i = 0; i < vi->qindex; i++) {
+        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
+        if (!elem) {
+            while (--i >= 0) {
+                vu_queue_unpop(dev, vq, vi->queue[i].elem, 0);
+            }
+            vi->qindex = 0;
+            g_warning("virtio-input queue full");
+            return;
+        }
+        vi->queue[i].elem = elem;
+    }
+
+    /* ... and finally pass them to the guest */
+    for (i = 0; i < vi->qindex; i++) {
+        elem = vi->queue[i].elem;
+        len = iov_from_buf(elem->in_sg, elem->in_num,
+                           0, &vi->queue[i].event, sizeof(virtio_input_event));
+        vu_queue_push(dev, vq, elem, len);
+        g_free(elem);
+    }
+
+    vu_queue_notify(&vi->dev.parent, vq);
+    vi->qindex = 0;
+}
+
+static void
+vi_evdev_watch(VuDev *dev, int condition, void *data)
+{
+    VuInput *vi = data;
+    int fd = vi->evdevfd;
+
+    g_debug("Got evdev condition %x", condition);
+
+    struct virtio_input_event virtio;
+    struct input_event evdev;
+    int rc;
+
+    for (;;) {
+        rc = read(fd, &evdev, sizeof(evdev));
+        if (rc != sizeof(evdev)) {
+            break;
+        }
+
+        g_debug("input %d %d %d", evdev.type, evdev.code, evdev.value);
+
+        virtio.type  = htole16(evdev.type);
+        virtio.code  = htole16(evdev.code);
+        virtio.value = htole32(evdev.value);
+        vi_input_send(vi, &virtio);
+    }
+}
+
+
+static void vi_handle_status(VuInput *vi, virtio_input_event *event)
+{
+    struct input_event evdev;
+    int rc;
+
+    if (gettimeofday(&evdev.time, NULL)) {
+        perror("vi_handle_status: gettimeofday");
+        return;
+    }
+
+    evdev.type = le16toh(event->type);
+    evdev.code = le16toh(event->code);
+    evdev.value = le32toh(event->value);
+
+    rc = write(vi->evdevfd, &evdev, sizeof(evdev));
+    if (rc == -1) {
+        perror("vi_host_handle_status: write");
+    }
+}
+
+static void vi_handle_sts(VuDev *dev, int qidx)
+{
+    VuInput *vi = container_of(dev, VuInput, dev.parent);
+    VuVirtq *vq = vu_get_queue(dev, qidx);
+    virtio_input_event event;
+    VuVirtqElement *elem;
+    int len;
+
+    g_debug("%s", G_STRFUNC);
+
+    for (;;) {
+        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
+        if (!elem) {
+            break;
+        }
+
+        memset(&event, 0, sizeof(event));
+        len = iov_to_buf(elem->out_sg, elem->out_num,
+                         0, &event, sizeof(event));
+        vi_handle_status(vi, &event);
+        vu_queue_push(dev, vq, elem, len);
+        g_free(elem);
+    }
+
+    vu_queue_notify(&vi->dev.parent, vq);
+}
+
+static void
+vi_panic(VuDev *dev, const char *msg)
+{
+    g_critical("%s\n", msg);
+    exit(EXIT_FAILURE);
+}
+
+static void
+vi_queue_set_started(VuDev *dev, int qidx, bool started)
+{
+    VuInput *vi = container_of(dev, VuInput, dev.parent);
+    VuVirtq *vq = vu_get_queue(dev, qidx);
+
+    g_debug("queue started %d:%d", qidx, started);
+
+    if (qidx == 1) {
+        vu_set_queue_handler(dev, vq, started ? vi_handle_sts : NULL);
+    }
+
+    started = vu_queue_started(dev, vu_get_queue(dev, 0)) &&
+        vu_queue_started(dev, vu_get_queue(dev, 1));
+
+    if (started && !vi->evsrc) {
+        vi->evsrc = vug_source_new(&vi->dev, vi->evdevfd,
+                                   G_IO_IN, vi_evdev_watch, vi);
+    }
+
+    if (!started && vi->evsrc) {
+        g_source_destroy(vi->evsrc);
+        vi->evsrc = NULL;
+    }
+}
+
+static virtio_input_config *
+vi_find_config(VuInput *vi, uint8_t select, uint8_t subsel)
+{
+    virtio_input_config *cfg;
+    int i;
+
+    for (i = 0; i < vi->config->len; i++) {
+        cfg = &g_array_index(vi->config, virtio_input_config, i);
+        if (select == cfg->select && subsel == cfg->subsel) {
+            return cfg;
+        }
+    }
+
+    return NULL;
+}
+
+static int vi_get_config(VuDev *dev, uint8_t *config, uint32_t len)
+{
+    VuInput *vi = container_of(dev, VuInput, dev.parent);
+
+    g_return_val_if_fail(len <= sizeof(*vi->sel_config), -1);
+
+    if (vi->sel_config) {
+        memcpy(config, vi->sel_config, len);
+    } else {
+        memset(config, 0, len);
+    }
+
+    return 0;
+}
+
+static int vi_set_config(VuDev *dev, const uint8_t *data,
+                         uint32_t offset, uint32_t size,
+                         uint32_t flags)
+{
+    VuInput *vi = container_of(dev, VuInput, dev.parent);
+    virtio_input_config *config = (virtio_input_config *)data;
+
+    vi->sel_config = vi_find_config(vi, config->select, config->subsel);
+
+    return 0;
+}
+
+static const VuDevIface vuiface = {
+    .queue_set_started = vi_queue_set_started,
+    .get_config = vi_get_config,
+    .set_config = vi_set_config,
+};
+
+static void
+vi_bits_config(VuInput *vi, int type, int count)
+{
+    virtio_input_config bits;
+    int rc, i, size = 0;
+
+    memset(&bits, 0, sizeof(bits));
+    rc = ioctl(vi->evdevfd, EVIOCGBIT(type, count / 8), bits.u.bitmap);
+    if (rc < 0) {
+        return;
+    }
+
+    for (i = 0; i < count / 8; i++) {
+        if (bits.u.bitmap[i]) {
+            size = i + 1;
+        }
+    }
+    if (size == 0) {
+        return;
+    }
+
+    bits.select = VIRTIO_INPUT_CFG_EV_BITS;
+    bits.subsel = type;
+    bits.size   = size;
+    g_array_append_val(vi->config, bits);
+}
+
+static char *opt_evdev;
+static int opt_fdnum = -1;
+static char *opt_socket_path;
+static gboolean opt_nograb;
+static gboolean opt_print_caps;
+
+static GOptionEntry entries[] = {
+    { "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &opt_print_caps,
+      "Print capabilities", NULL },
+    { "no-grab", 'n', 0, G_OPTION_ARG_NONE, &opt_nograb,
+      "Don't grab device", NULL },
+    { "fd", 'f', 0, G_OPTION_ARG_INT, &opt_fdnum,
+      "Use inherited fd socket", "FDNUM" },
+    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
+      "Use UNIX socket path", "PATH" },
+    { "evdev-path", 'p', 0, G_OPTION_ARG_FILENAME, &opt_evdev,
+      "evdev input device path", "PATH" },
+    { NULL, }
+};
+
+int
+main(int argc, char *argv[])
+{
+    GMainLoop *loop = NULL;
+    VuInput vi = { 0, };
+    int rc, ver, fd;
+    virtio_input_config id;
+    struct input_id ids;
+    GError *error = NULL;
+    GOptionContext *context;
+
+    context = g_option_context_new(NULL);
+    g_option_context_add_main_entries(context, entries, NULL);
+    if (!g_option_context_parse(context, &argc, &argv, &error)) {
+        g_printerr("Option parsing failed: %s\n", error->message);
+        exit(EXIT_FAILURE);
+    }
+    if (opt_print_caps) {
+        g_print("{\n");
+        g_print("  \"type\": \"input\",\n");
+        g_print("  \"features\": [\n");
+        g_print("    \"evdev-path\",\n");
+        g_print("    \"no-grab\"\n");
+        g_print("  ]\n");
+        g_print("}\n");
+        exit(EXIT_SUCCESS);
+    }
+    if (!opt_evdev) {
+        g_printerr("Please specify an evdev path\n");
+        exit(EXIT_FAILURE);
+    }
+    if ((!!opt_socket_path + (opt_fdnum != -1)) != 1) {
+        g_printerr("Please specify either --fd or --socket-path\n");
+        exit(EXIT_FAILURE);
+    }
+
+    vi.evdevfd = open(opt_evdev, O_RDWR);
+    if (vi.evdevfd < 0) {
+        g_printerr("Failed to open evdev: %s\n", g_strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    rc = ioctl(vi.evdevfd, EVIOCGVERSION, &ver);
+    if (rc < 0) {
+        g_printerr("%s: is not an evdev device\n", argv[1]);
+        exit(EXIT_FAILURE);
+    }
+
+    if (!opt_nograb) {
+        rc = ioctl(vi.evdevfd, EVIOCGRAB, 1);
+        if (rc < 0) {
+            g_printerr("Failed to grab device\n");
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    vi.config = g_array_new(false, false, sizeof(virtio_input_config));
+    memset(&id, 0, sizeof(id));
+    ioctl(vi.evdevfd, EVIOCGNAME(sizeof(id.u.string) - 1), id.u.string);
+    id.select = VIRTIO_INPUT_CFG_ID_NAME;
+    id.size = strlen(id.u.string);
+    g_array_append_val(vi.config, id);
+
+    if (ioctl(vi.evdevfd, EVIOCGID, &ids) == 0) {
+        memset(&id, 0, sizeof(id));
+        id.select = VIRTIO_INPUT_CFG_ID_DEVIDS;
+        id.size = sizeof(struct virtio_input_devids);
+        id.u.ids.bustype = cpu_to_le16(ids.bustype);
+        id.u.ids.vendor  = cpu_to_le16(ids.vendor);
+        id.u.ids.product = cpu_to_le16(ids.product);
+        id.u.ids.version = cpu_to_le16(ids.version);
+        g_array_append_val(vi.config, id);
+    }
+
+    vi_bits_config(&vi, EV_KEY, KEY_CNT);
+    vi_bits_config(&vi, EV_REL, REL_CNT);
+    vi_bits_config(&vi, EV_ABS, ABS_CNT);
+    vi_bits_config(&vi, EV_MSC, MSC_CNT);
+    vi_bits_config(&vi, EV_SW,  SW_CNT);
+    g_debug("config length: %u", vi.config->len);
+
+    if (opt_socket_path) {
+        int lsock = unix_listen(opt_socket_path, &error_fatal);
+        fd = accept(lsock, NULL, NULL);
+        close(lsock);
+    } else {
+        fd = opt_fdnum;
+    }
+    if (fd == -1) {
+        g_printerr("Invalid socket");
+        exit(EXIT_FAILURE);
+    }
+    vug_init(&vi.dev, fd, vi_panic, &vuiface);
+
+    loop = g_main_loop_new(NULL, FALSE);
+    g_main_loop_run(loop);
+    g_main_loop_unref(loop);
+
+    vug_deinit(&vi.dev);
+
+    if (vi.evsrc) {
+        g_source_unref(vi.evsrc);
+    }
+    g_array_free(vi.config, TRUE);
+    g_free(vi.queue);
+    return 0;
+}
diff --git a/MAINTAINERS b/MAINTAINERS
index a73a61a546..8a87bc176d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1531,6 +1531,7 @@ S: Maintained
 F: hw/input/vhost-user-input.c
 F: hw/input/virtio-input*.c
 F: include/hw/virtio/virtio-input.h
+F: contrib/vhost-user-input/*
 
 virtio-serial
 M: Amit Shah <amit@kernel.org>
diff --git a/Makefile b/Makefile
index 66d5c65156..fe5c02f9a3 100644
--- a/Makefile
+++ b/Makefile
@@ -406,6 +406,7 @@ dummy := $(call unnest-vars,, \
                 libvhost-user-obj-y \
                 vhost-user-scsi-obj-y \
                 vhost-user-blk-obj-y \
+                vhost-user-input-obj-y \
                 qga-vss-dll-obj-y \
                 block-obj-y \
                 block-obj-m \
@@ -615,6 +616,16 @@ rdmacm-mux$(EXESUF): LIBS += "-libumad"
 rdmacm-mux$(EXESUF): $(rdmacm-mux-obj-y) $(COMMON_LDADDS)
 	$(call LINK, $^)
 
+ifdef CONFIG_VHOST_USER_INPUT
+ifdef CONFIG_LINUX
+vhost-user-input$(EXESUF): $(vhost-user-input-obj-y) libvhost-user.a libqemuutil.a
+	$(call LINK, $^)
+
+# build by default, do not install
+all: vhost-user-input$(EXESUF)
+endif
+endif
+
 module_block.h: $(SRC_PATH)/scripts/modules/module_block.py config-host.mak
 	$(call quiet-command,$(PYTHON) $< $@ \
 	$(addprefix $(SRC_PATH)/,$(patsubst %.mo,%.c,$(block-obj-m))), \
diff --git a/Makefile.objs b/Makefile.objs
index cf065de5ed..27502b7df1 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -122,6 +122,7 @@ vhost-user-scsi.o-libs := $(LIBISCSI_LIBS)
 vhost-user-scsi-obj-y = contrib/vhost-user-scsi/
 vhost-user-blk-obj-y = contrib/vhost-user-blk/
 rdmacm-mux-obj-y = contrib/rdmacm-mux/
+vhost-user-input-obj-y = contrib/vhost-user-input/
 
 ######################################################################
 trace-events-subdirs =
diff --git a/contrib/vhost-user-input/Makefile.objs b/contrib/vhost-user-input/Makefile.objs
new file mode 100644
index 0000000000..b1fad90d51
--- /dev/null
+++ b/contrib/vhost-user-input/Makefile.objs
@@ -0,0 +1 @@
+vhost-user-input-obj-y = main.o
-- 
2.21.0.777.g83232e3864