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* [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input
@ 2019-02-07 16:54 Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends Marc-André Lureau
                   ` (11 more replies)
  0 siblings, 12 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Hi,

This series is based on previously discussed "[PATCH v4 00/29]
vhost-user for input & GPU" and "vhost-user: define conventions for
vhost-user backends" work. The GPU part is left off for now.

This series introduces a "vhost-user-backend": a convenience object
for vhost-user devices, for common command line and initilization
handling. As a simple showcase, a "vhost-user-input-pci" device is
introduced, which can be used with the "contrib: add vhost-user-input"
example. vhost-user-input isn't meant to be installed, discovered or
used by libvirt: no installation is done (no vhost-user JSON file is
provided either).

thanks

v2:
- rebased (VhostUserInputPCI got most of the changes, due to split)
- added "RFC: add explicit can_migrate to
  vhost_user_backend_dev_init()" to attempt to address Michael
  concerns about migration.

Marc-André Lureau (12):
  vhost-user: define conventions for vhost-user backends
  vhost-user: simplify vhost_user_init/vhost_user_cleanup
  libvhost-user: exit by default on VHOST_USER_NONE
  vhost-user: wrap some read/write with retry handling
  Add vhost-user-backend
  vhost-user: split vhost_user_read()
  vhost-user: add vhost_user_input_get_config()
  libvhost-user-glib: export vug_source_new()
  libvhost-user: add vu_queue_unpop()
  Add vhost-user-input-pci
  contrib: add vhost-user-input
  RFC: add explicit can_migrate to vhost_user_backend_dev_init()

 contrib/libvhost-user/libvhost-user-glib.h |   3 +
 contrib/libvhost-user/libvhost-user.h      |  15 +
 include/hw/virtio/vhost-backend.h          |   4 +
 include/hw/virtio/vhost-user-blk.h         |   2 +-
 include/hw/virtio/vhost-user-scsi.h        |   2 +-
 include/hw/virtio/vhost-user.h             |   2 +-
 include/hw/virtio/virtio-input.h           |  14 +
 include/sysemu/vhost-user-backend.h        |  60 ++++
 backends/cryptodev-vhost-user.c            |  18 +-
 backends/vhost-user.c                      | 249 +++++++++++++
 contrib/libvhost-user/libvhost-user-glib.c |  11 +-
 contrib/libvhost-user/libvhost-user.c      |  19 +-
 contrib/vhost-user-input/main.c            | 398 +++++++++++++++++++++
 hw/block/vhost-user-blk.c                  |  22 +-
 hw/input/vhost-user-input.c                | 110 ++++++
 hw/scsi/vhost-user-scsi.c                  |  20 +-
 hw/virtio/vhost-stub.c                     |   4 +-
 hw/virtio/vhost-user-input-pci.c           |  53 +++
 hw/virtio/vhost-user.c                     | 118 +++++-
 net/vhost-user.c                           |  13 +-
 vl.c                                       |   3 +-
 MAINTAINERS                                |   5 +
 Makefile                                   |   3 +
 Makefile.objs                              |   1 +
 backends/Makefile.objs                     |   3 +-
 configure                                  |   3 +
 contrib/vhost-user-input/Makefile.objs     |   1 +
 default-configs/virtio.mak                 |   1 +
 docs/interop/vhost-user.json               | 219 ++++++++++++
 docs/interop/vhost-user.txt                | 109 +++++-
 hw/input/Makefile.objs                     |   1 +
 hw/virtio/Makefile.objs                    |   1 +
 qemu-options.hx                            |  20 ++
 33 files changed, 1420 insertions(+), 87 deletions(-)
 create mode 100644 include/sysemu/vhost-user-backend.h
 create mode 100644 backends/vhost-user.c
 create mode 100644 contrib/vhost-user-input/main.c
 create mode 100644 hw/input/vhost-user-input.c
 create mode 100644 hw/virtio/vhost-user-input-pci.c
 create mode 100644 contrib/vhost-user-input/Makefile.objs
 create mode 100644 docs/interop/vhost-user.json

-- 
2.20.1.519.g8feddda32c

^ permalink raw reply	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 17:42   ` Eric Blake
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 02/12] vhost-user: simplify vhost_user_init/vhost_user_cleanup Marc-André Lureau
                   ` (10 subsequent siblings)
  11 siblings, 1 reply; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

As discussed during "[PATCH v4 00/29] vhost-user for input & GPU"
review, let's define a common set of backend conventions to help with
management layer implementation, and interoperability.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
 MAINTAINERS                  |   1 +
 docs/interop/vhost-user.json | 219 +++++++++++++++++++++++++++++++++++
 docs/interop/vhost-user.txt  | 101 +++++++++++++++-
 3 files changed, 319 insertions(+), 2 deletions(-)
 create mode 100644 docs/interop/vhost-user.json

diff --git a/MAINTAINERS b/MAINTAINERS
index 9a76845581..16b6264412 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1421,6 +1421,7 @@ vhost
 M: Michael S. Tsirkin <mst@redhat.com>
 S: Supported
 F: hw/*/*vhost*
+F: docs/interop/vhost-user.json
 F: docs/interop/vhost-user.txt
 F: contrib/vhost-user-*/
 
diff --git a/docs/interop/vhost-user.json b/docs/interop/vhost-user.json
new file mode 100644
index 0000000000..91b5bf499e
--- /dev/null
+++ b/docs/interop/vhost-user.json
@@ -0,0 +1,219 @@
+# -*- Mode: Python -*-
+#
+# Copyright (C) 2018 Red Hat, Inc.
+#
+# Authors:
+#  Marc-André Lureau <marcandre.lureau@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later. See the COPYING file in the top-level directory.
+
+##
+# = vhost user backend discovery & capabilities
+##
+
+##
+# @VHostUserBackendType:
+#
+# List the various vhost user backend types.
+#
+# @net: virtio net
+# @block: virtio block
+# @console: virtio console
+# @rng: virtio rng
+# @balloon: virtio balloon
+# @rpmsg: virtio remote processor messaging
+# @scsi: virtio scsi
+# @9p: 9p virtio console
+# @rproc-serial: virtio remoteproc serial link
+# @caif: virtio caif
+# @gpu: virtio gpu
+# @input: virtio input
+# @vsock: virtio vsock transport
+# @crypto: virtio crypto
+#
+# Since: 3.2
+##
+{
+  'enum': 'VHostUserBackendType',
+  'data': [ 'net', 'block', 'console', 'rng', 'balloon', 'rpmsg',
+            'scsi', '9p', 'rproc-serial', 'caif', 'gpu', 'input', 'vsock',
+            'crypto' ]
+}
+
+##
+# @VHostUserBackendInputFeature:
+#
+# List of vhost user "input" features.
+#
+# @evdev-path: The --evdev-path command line option is supported.
+# @no-grab: The --no-grab command line option is supported.
+#
+# Since: 3.2
+##
+{
+  'enum': 'VHostUserBackendInputFeature',
+  'data': [ 'evdev-path', 'no-grab' ]
+}
+
+##
+# @VHostUserBackendCapabilitiesInput:
+#
+# Capabilities reported by vhost user "input" backends
+#
+# @features: list of supported features.
+#
+# Since: 3.2
+##
+{
+  'struct': 'VHostUserBackendCapabilitiesInput',
+  'data': {
+    'features': [ 'VHostUserBackendInputFeature' ]
+  }
+}
+
+##
+# @VHostUserBackendGPUFeature:
+#
+# List of vhost user "gpu" features.
+#
+# @render-node: The --render-node command line option is supported.
+# @virgl: The --virgl command line option is supported.
+#
+# Since: 3.2
+##
+{
+  'enum': 'VHostUserBackendGPUFeature',
+  'data': [ 'render-node', 'virgl' ]
+}
+
+##
+# @VHostUserBackendCapabilitiesGPU:
+#
+# Capabilities reported by vhost user "gpu" backends.
+#
+# @features: list of supported features.
+#
+# Since: 3.2
+##
+{
+  'struct': 'VHostUserBackendCapabilitiesGPU',
+  'data': {
+    'features': [ 'VHostUserBackendGPUFeature' ]
+  }
+}
+
+##
+# @VHostUserBackendCapabilities:
+#
+# Capabilities reported by vhost user backends.
+#
+# @type: The vhost user backend type.
+#
+# Since: 3.2
+##
+{
+  'union': 'VHostUserBackendCapabilities',
+  'base': { 'type': 'VHostUserBackendType' },
+  'discriminator': 'type',
+  'data': {
+    'input': 'VHostUserBackendCapabilitiesInput',
+    'gpu': 'VHostUserBackendCapabilitiesGPU'
+  }
+}
+
+##
+# @VhostUserBackend:
+#
+# Describes a vhost user backend to management software.
+#
+# It is possible for multiple @VhostUserBackend elements to match the
+# search criteria of management software. Applications thus need rules
+# to pick one of the many matches, and users need the ability to
+# override distro defaults.
+#
+# It is recommended to create vhost user backend JSON files (each
+# containing a single @VhostUserBackend root element) with a
+# double-digit prefix, for example "50-qemu-gpu.json",
+# "50-crosvm-gpu.json", etc, so they can be sorted in predictable
+# order. The backend JSON files should be searched for in three
+# directories:
+#
+#   - /usr/share/qemu/vhost-user -- populated by distro-provided
+#                                   packages (XDG_DATA_DIRS covers
+#                                   /usr/share by default),
+#
+#   - /etc/qemu/vhost-user -- exclusively for sysadmins' local additions,
+#
+#   - $XDG_CONFIG_HOME/qemu/vhost-user -- exclusively for per-user local
+#                                         additions (XDG_CONFIG_HOME
+#                                         defaults to $HOME/.config).
+#
+# Top-down, the list of directories goes from general to specific.
+#
+# Management software should build a list of files from all three
+# locations, then sort the list by filename (i.e., last pathname
+# component). Management software should choose the first JSON file on
+# the sorted list that matches the search criteria. If a more specific
+# directory has a file with same name as a less specific directory, then
+# the file in the more specific directory takes effect. If the more
+# specific file is zero length, it hides the less specific one.
+#
+# For example, if a distro ships
+#
+#   - /usr/share/qemu/vhost-user/50-qemu-gpu.json
+#
+#   - /usr/share/qemu/vhost-user/50-crosvm-gpu.json
+#
+# then the sysadmin can prevent the default QEMU being used at all with
+#
+#   $ touch /etc/qemu/vhost-user/50-qemu-gpu.json
+#
+# The sysadmin can replace/alter the distro default OVMF with
+#
+#   $ vim /etc/qemu/vhost-user/50-qemu-gpu.json
+#
+# or they can provide a parallel QEMU GPU with higher priority
+#
+#   $ vim /etc/qemu/vhost-user/10-qemu-gpu.json
+#
+# or they can provide a parallel OVMF with lower priority
+#
+#   $ vim /etc/qemu/vhost-user/99-qemu-gpu.json
+#
+# @type: The vhost user backend type.
+#
+# @description: Provides a human-readable description of the backend.
+#               Management software may or may not display @description.
+#
+# @binary: Absolute path to the backend binary.
+#
+# @tags: An optional list of auxiliary strings associated with the
+#        backend for which @description is not appropriate, due to the
+#        latter's possible exposure to the end-user. @tags serves
+#        development and debugging purposes only, and management
+#        software shall explicitly ignore it.
+#
+# Since: 3.2
+#
+# Example:
+#
+# {
+#   "description": "QEMU vhost-user-gpu",
+#   "type": "gpu",
+#   "binary": "/usr/libexec/qemu/vhost-user-gpu",
+#   "tags": [
+#     "CONFIG_OPENGL_DMABUF=y"
+#   ]
+# }
+#
+##
+{
+  'struct' : 'VhostUserBackend',
+  'data'   : {
+    'description': 'str',
+    'type': 'VHostUserBackendType',
+    'binary': 'str',
+    '*tags': [ 'str' ]
+  }
+}
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
index c2194711d9..cefec9ffe1 100644
--- a/docs/interop/vhost-user.txt
+++ b/docs/interop/vhost-user.txt
@@ -17,8 +17,13 @@ The protocol defines 2 sides of the communication, master and slave. Master is
 the application that shares its virtqueues, in our case QEMU. Slave is the
 consumer of the virtqueues.
 
-In the current implementation QEMU is the Master, and the Slave is intended to
-be a software Ethernet switch running in user space, such as Snabbswitch.
+In the current implementation QEMU is the Master, and the Slave is the
+external process consuming the virtio queues, for example a software
+Ethernet switch running in user space, such as Snabbswitch, or a block
+device backend processing read & write to a virtual disk. In order to
+facilitate interoperability between various backend implementations,
+it is recommended to follow the "Backend program conventions"
+described in this document.
 
 Master and slave can be either a client (i.e. connecting) or server (listening)
 in the socket communication.
@@ -835,3 +840,95 @@ resilient for selective requests.
 For the message types that already solicit a reply from the client, the
 presence of VHOST_USER_PROTOCOL_F_REPLY_ACK or need_reply bit being set brings
 no behavioural change. (See the 'Communication' section for details.)
+
+Backend program conventions
+---------------------------
+
+vhost-user backends can provide various devices & services and may
+need to be configured manually depending on the use case. However, it
+is a good idea to follow the conventions listed here when
+possible. Users, QEMU or libvirt, can then rely on some common
+behaviour to avoid heterogenous configuration and management of the
+backend programs and facilitate interoperability.
+
+Each backend installed on a host system should come with at least one
+JSON file that conforms to the vhost-user.json schema. Each file
+informs the management applications about the backend type, and binary
+location. In addition, it defines rules for management apps for
+picking the highest priority backend when multiple match the search
+criteria (see @VhostUserBackend documentation in the schema file).
+
+If the backend is not capable of enabling a requested feature on the
+host (such as 3D acceleration with virgl), or the initialization
+failed, the backend should fail to start early and exit with a status
+!= 0. It may also print a message to stderr for further details.
+
+The backend program must not daemonize itself, but it may be
+daemonized by the management layer. It may also have a restricted
+access to the system.
+
+File descriptors 0, 1 and 2 will exist, and have regular
+stdin/stdout/stderr usage (they may have been redirected to /dev/null
+by the management layer, or to a log handler).
+
+The backend program must end (as quickly and cleanly as possible) when
+the SIGTERM signal is received. Eventually, it may be SIGKILL by the
+management layer after a few seconds.
+
+The following command line options have an expected behaviour. They
+are mandatory, unless explicitly said differently:
+
+* --socket-path=PATH
+
+This option specify the location of the vhost-user Unix domain socket.
+It is incompatible with --fd.
+
+* --fd=FDNUM
+
+When this argument is given, the backend program is started with the
+vhost-user socket as file descriptor FDNUM. It is incompatible with
+--socket-path.
+
+* --print-capabilities
+
+Output to stdout the backend capabilities in JSON format, and then
+exit successfully. Other options and arguments should be ignored, and
+the backend program should not perform its normal function.  The
+capabilities can be reported dynamically depending on the host
+capabilities.
+
+The JSON output is described in the vhost-user.json schema, by
+@VHostUserBackendCapabilities.  Example:
+{
+  "type": "foo",
+  "features": [
+    "feature-a",
+    "feature-b"
+  ]
+}
+
+vhost-user-input
+----------------
+
+Command line options:
+
+* --evdev-path=PATH (optional)
+
+Specify the linux input device.
+
+* --no-grab (optional)
+
+Do no request exclusive access to the input device.
+
+vhost-user-gpu
+--------------
+
+Command line options:
+
+* --render-node=PATH (optional)
+
+Specify the GPU DRM render node.
+
+* --virgl (optional)
+
+Enable virgl rendering support.
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 02/12] vhost-user: simplify vhost_user_init/vhost_user_cleanup
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 03/12] libvhost-user: exit by default on VHOST_USER_NONE Marc-André Lureau
                   ` (9 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel
  Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau,
	Gonglei, Kevin Wolf, Max Reitz, Paolo Bonzini, Fam Zheng,
	Jason Wang, open list:Block layer core

Take a VhostUserState* that can be pre-allocated, and initialize it
with the associated chardev.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
---
 include/hw/virtio/vhost-user-blk.h  |  2 +-
 include/hw/virtio/vhost-user-scsi.h |  2 +-
 include/hw/virtio/vhost-user.h      |  2 +-
 backends/cryptodev-vhost-user.c     | 18 ++++--------------
 hw/block/vhost-user-blk.c           | 22 ++++------------------
 hw/scsi/vhost-user-scsi.c           | 20 ++++----------------
 hw/virtio/vhost-stub.c              |  4 ++--
 hw/virtio/vhost-user.c              | 16 ++++++++++++----
 net/vhost-user.c                    | 13 ++++---------
 9 files changed, 33 insertions(+), 66 deletions(-)

diff --git a/include/hw/virtio/vhost-user-blk.h b/include/hw/virtio/vhost-user-blk.h
index d52944aeeb..a8a106eecb 100644
--- a/include/hw/virtio/vhost-user-blk.h
+++ b/include/hw/virtio/vhost-user-blk.h
@@ -36,7 +36,7 @@ typedef struct VHostUserBlk {
     uint32_t queue_size;
     uint32_t config_wce;
     struct vhost_dev dev;
-    VhostUserState *vhost_user;
+    VhostUserState vhost_user;
 } VHostUserBlk;
 
 #endif
diff --git a/include/hw/virtio/vhost-user-scsi.h b/include/hw/virtio/vhost-user-scsi.h
index e429cacd8e..738f9288bd 100644
--- a/include/hw/virtio/vhost-user-scsi.h
+++ b/include/hw/virtio/vhost-user-scsi.h
@@ -30,7 +30,7 @@
 
 typedef struct VHostUserSCSI {
     VHostSCSICommon parent_obj;
-    VhostUserState *vhost_user;
+    VhostUserState vhost_user;
 } VHostUserSCSI;
 
 #endif /* VHOST_USER_SCSI_H */
diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h
index fd660393a0..811e325f42 100644
--- a/include/hw/virtio/vhost-user.h
+++ b/include/hw/virtio/vhost-user.h
@@ -22,7 +22,7 @@ typedef struct VhostUserState {
     VhostUserHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostUserState;
 
-VhostUserState *vhost_user_init(void);
+bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp);
 void vhost_user_cleanup(VhostUserState *user);
 
 #endif
diff --git a/backends/cryptodev-vhost-user.c b/backends/cryptodev-vhost-user.c
index d539f14d59..1052a5d0e9 100644
--- a/backends/cryptodev-vhost-user.c
+++ b/backends/cryptodev-vhost-user.c
@@ -47,7 +47,7 @@
 typedef struct CryptoDevBackendVhostUser {
     CryptoDevBackend parent_obj;
 
-    VhostUserState *vhost_user;
+    VhostUserState vhost_user;
     CharBackend chr;
     char *chr_name;
     bool opened;
@@ -104,7 +104,7 @@ cryptodev_vhost_user_start(int queues,
             continue;
         }
 
-        options.opaque = s->vhost_user;
+        options.opaque = &s->vhost_user;
         options.backend_type = VHOST_BACKEND_TYPE_USER;
         options.cc = b->conf.peers.ccs[i];
         s->vhost_crypto[i] = cryptodev_vhost_init(&options);
@@ -182,7 +182,6 @@ static void cryptodev_vhost_user_init(
     size_t i;
     Error *local_err = NULL;
     Chardev *chr;
-    VhostUserState *user;
     CryptoDevBackendClient *cc;
     CryptoDevBackendVhostUser *s =
                       CRYPTODEV_BACKEND_VHOST_USER(backend);
@@ -213,15 +212,10 @@ static void cryptodev_vhost_user_init(
         }
     }
 
-    user = vhost_user_init();
-    if (!user) {
-        error_setg(errp, "Failed to init vhost_user");
+    if (!vhost_user_init(&s->vhost_user, &s->chr, errp)) {
         return;
     }
 
-    user->chr = &s->chr;
-    s->vhost_user = user;
-
     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
                      cryptodev_vhost_user_event, NULL, s, NULL, true);
 
@@ -307,11 +301,7 @@ static void cryptodev_vhost_user_cleanup(
         }
     }
 
-    if (s->vhost_user) {
-        vhost_user_cleanup(s->vhost_user);
-        g_free(s->vhost_user);
-        s->vhost_user = NULL;
-    }
+    vhost_user_cleanup(&s->vhost_user);
 }
 
 static void cryptodev_vhost_user_set_chardev(Object *obj,
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 44ac814016..767c734a81 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -253,7 +253,6 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
-    VhostUserState *user;
     struct vhost_virtqueue *vqs = NULL;
     int i, ret;
 
@@ -272,15 +271,10 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    user = vhost_user_init();
-    if (!user) {
-        error_setg(errp, "vhost-user-blk: failed to init vhost_user");
+    if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
         return;
     }
 
-    user->chr = &s->chardev;
-    s->vhost_user = user;
-
     virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
                 sizeof(struct virtio_blk_config));
 
@@ -297,7 +291,7 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 
     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
 
-    ret = vhost_dev_init(&s->dev, s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
+    ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
     if (ret < 0) {
         error_setg(errp, "vhost-user-blk: vhost initialization failed: %s",
                    strerror(-ret));
@@ -322,10 +316,7 @@ vhost_err:
 virtio_err:
     g_free(vqs);
     virtio_cleanup(vdev);
-
-    vhost_user_cleanup(user);
-    g_free(user);
-    s->vhost_user = NULL;
+    vhost_user_cleanup(&s->vhost_user);
 }
 
 static void vhost_user_blk_device_unrealize(DeviceState *dev, Error **errp)
@@ -338,12 +329,7 @@ static void vhost_user_blk_device_unrealize(DeviceState *dev, Error **errp)
     vhost_dev_cleanup(&s->dev);
     g_free(vqs);
     virtio_cleanup(vdev);
-
-    if (s->vhost_user) {
-        vhost_user_cleanup(s->vhost_user);
-        g_free(s->vhost_user);
-        s->vhost_user = NULL;
-    }
+    vhost_user_cleanup(&s->vhost_user);
 }
 
 static void vhost_user_blk_instance_init(Object *obj)
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index 6728878a52..8b1e6876db 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -69,7 +69,6 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
     VHostUserSCSI *s = VHOST_USER_SCSI(dev);
     VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
-    VhostUserState *user;
     Error *err = NULL;
     int ret;
 
@@ -86,30 +85,24 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    user = vhost_user_init();
-    if (!user) {
-        error_setg(errp, "vhost-user-scsi: failed to init vhost_user");
+    if (!vhost_user_init(&s->vhost_user, &vs->conf.chardev, errp)) {
         return;
     }
-    user->chr = &vs->conf.chardev;
 
     vsc->dev.nvqs = 2 + vs->conf.num_queues;
     vsc->dev.vqs = g_new(struct vhost_virtqueue, vsc->dev.nvqs);
     vsc->dev.vq_index = 0;
     vsc->dev.backend_features = 0;
 
-    ret = vhost_dev_init(&vsc->dev, user,
+    ret = vhost_dev_init(&vsc->dev, &s->vhost_user,
                          VHOST_BACKEND_TYPE_USER, 0);
     if (ret < 0) {
         error_setg(errp, "vhost-user-scsi: vhost initialization failed: %s",
                    strerror(-ret));
-        vhost_user_cleanup(user);
-        g_free(user);
+        vhost_user_cleanup(&s->vhost_user);
         return;
     }
 
-    s->vhost_user = user;
-
     /* Channel and lun both are 0 for bootable vhost-user-scsi disk */
     vsc->channel = 0;
     vsc->lun = 0;
@@ -130,12 +123,7 @@ static void vhost_user_scsi_unrealize(DeviceState *dev, Error **errp)
     g_free(vqs);
 
     virtio_scsi_common_unrealize(dev, errp);
-
-    if (s->vhost_user) {
-        vhost_user_cleanup(s->vhost_user);
-        g_free(s->vhost_user);
-        s->vhost_user = NULL;
-    }
+    vhost_user_cleanup(&s->vhost_user);
 }
 
 static Property vhost_user_scsi_properties[] = {
diff --git a/hw/virtio/vhost-stub.c b/hw/virtio/vhost-stub.c
index 049089b5e2..c175148fce 100644
--- a/hw/virtio/vhost-stub.c
+++ b/hw/virtio/vhost-stub.c
@@ -7,9 +7,9 @@ bool vhost_has_free_slot(void)
     return true;
 }
 
-VhostUserState *vhost_user_init(void)
+bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp)
 {
-    return NULL;
+    return false;
 }
 
 void vhost_user_cleanup(VhostUserState *user)
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 564a31d12c..a0e8a81857 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1739,17 +1739,24 @@ static bool vhost_user_mem_section_filter(struct vhost_dev *dev,
     return result;
 }
 
-VhostUserState *vhost_user_init(void)
+bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp)
 {
-    VhostUserState *user = g_new0(struct VhostUserState, 1);
-
-    return user;
+    if (user->chr) {
+        error_setg(errp, "Cannot initialize vhost-user state");
+        return false;
+    }
+    user->chr = chr;
+    return true;
 }
 
 void vhost_user_cleanup(VhostUserState *user)
 {
     int i;
 
+    if (!user->chr) {
+        return;
+    }
+
     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
         if (user->notifier[i].addr) {
             object_unparent(OBJECT(&user->notifier[i].mr));
@@ -1757,6 +1764,7 @@ void vhost_user_cleanup(VhostUserState *user)
             user->notifier[i].addr = NULL;
         }
     }
+    user->chr = NULL;
 }
 
 const VhostOps user_ops = {
diff --git a/net/vhost-user.c b/net/vhost-user.c
index a39f9c9974..cea78b81f6 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -291,19 +291,14 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
 {
     Error *err = NULL;
     NetClientState *nc, *nc0 = NULL;
-    VhostUserState *user = NULL;
     NetVhostUserState *s = NULL;
+    VhostUserState *user;
     int i;
 
     assert(name);
     assert(queues > 0);
 
-    user = vhost_user_init();
-    if (!user) {
-        error_report("failed to init vhost_user");
-        goto err;
-    }
-
+    user = g_new0(struct VhostUserState, 1);
     for (i = 0; i < queues; i++) {
         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
@@ -312,11 +307,11 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
         if (!nc0) {
             nc0 = nc;
             s = DO_UPCAST(NetVhostUserState, nc, nc);
-            if (!qemu_chr_fe_init(&s->chr, chr, &err)) {
+            if (!qemu_chr_fe_init(&s->chr, chr, &err) ||
+                !vhost_user_init(user, &s->chr, &err)) {
                 error_report_err(err);
                 goto err;
             }
-            user->chr = &s->chr;
         }
         s = DO_UPCAST(NetVhostUserState, nc, nc);
         s->vhost_user = user;
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 03/12] libvhost-user: exit by default on VHOST_USER_NONE
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 02/12] vhost-user: simplify vhost_user_init/vhost_user_cleanup Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 04/12] vhost-user: wrap some read/write with retry handling Marc-André Lureau
                   ` (8 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Since commit 2566378d6d13bf4d28c7770bdbda5f7682594bbe, libvhost-user
no longer panics on disconnect (rc == 0), and instead silently ignores
an invalid VHOST_USER_NONE message.

Without extra work from the API user, this will simply busy-loop on
HUP events. The obvious thing to do is to exit(0) instead, while
additional or different work can be done by overriding
iface->process_msg().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
---
 contrib/libvhost-user/libvhost-user.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index 3f14b4138b..fcf5014240 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -1285,7 +1285,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
     case VHOST_USER_SET_CONFIG:
         return vu_set_config(dev, vmsg);
     case VHOST_USER_NONE:
-        break;
+        /* if you need processing before exit, override iface->process_msg */
+        exit(0);
     case VHOST_USER_POSTCOPY_ADVISE:
         return vu_set_postcopy_advise(dev, vmsg);
     case VHOST_USER_POSTCOPY_LISTEN:
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 04/12] vhost-user: wrap some read/write with retry handling
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (2 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 03/12] libvhost-user: exit by default on VHOST_USER_NONE Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend Marc-André Lureau
                   ` (7 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/virtio/vhost-user.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index a0e8a81857..b2e1175c1e 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -964,7 +964,10 @@ static void slave_read(void *opaque)
     iov.iov_base = &hdr;
     iov.iov_len = VHOST_USER_HDR_SIZE;
 
-    size = recvmsg(u->slave_fd, &msgh, 0);
+    do {
+        size = recvmsg(u->slave_fd, &msgh, 0);
+    } while (size < 0 && (errno == EINTR || errno == EAGAIN));
+
     if (size != VHOST_USER_HDR_SIZE) {
         error_report("Failed to read from slave.");
         goto err;
@@ -993,7 +996,10 @@ static void slave_read(void *opaque)
     }
 
     /* Read payload */
-    size = read(u->slave_fd, &payload, hdr.size);
+    do {
+        size = read(u->slave_fd, &payload, hdr.size);
+    } while (size < 0 && (errno == EINTR || errno == EAGAIN));
+
     if (size != hdr.size) {
         error_report("Failed to read payload from slave.");
         goto err;
@@ -1041,7 +1047,10 @@ static void slave_read(void *opaque)
         iovec[1].iov_base = &payload;
         iovec[1].iov_len = hdr.size;
 
-        size = writev(u->slave_fd, iovec, ARRAY_SIZE(iovec));
+        do {
+            size = writev(u->slave_fd, iovec, ARRAY_SIZE(iovec));
+        } while (size < 0 && (errno == EINTR || errno == EAGAIN));
+
         if (size != VHOST_USER_HDR_SIZE + hdr.size) {
             error_report("Failed to send msg reply to slave.");
             goto err;
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (3 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 04/12] vhost-user: wrap some read/write with retry handling Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 17:36   ` Michael S. Tsirkin
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 06/12] vhost-user: split vhost_user_read() Marc-André Lureau
                   ` (6 subsequent siblings)
  11 siblings, 1 reply; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel
  Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau, Paolo Bonzini

Create a vhost-user-backend object that holds a connection to a
vhost-user backend and can be referenced from virtio devices that
support it. See later patches for input & gpu usage.

A chardev must be specified to communicate with the vhost-user
backend, ex: -chardev socket,id=char0,path=/tmp/foo.sock -object
vhost-user-backend,id=vuid,chardev=char0.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/sysemu/vhost-user-backend.h |  60 +++++++
 backends/vhost-user.c               | 244 ++++++++++++++++++++++++++++
 vl.c                                |   3 +-
 MAINTAINERS                         |   2 +
 backends/Makefile.objs              |   3 +-
 qemu-options.hx                     |  20 +++
 6 files changed, 330 insertions(+), 2 deletions(-)
 create mode 100644 include/sysemu/vhost-user-backend.h
 create mode 100644 backends/vhost-user.c

diff --git a/include/sysemu/vhost-user-backend.h b/include/sysemu/vhost-user-backend.h
new file mode 100644
index 0000000000..60f811cae7
--- /dev/null
+++ b/include/sysemu/vhost-user-backend.h
@@ -0,0 +1,60 @@
+/*
+ * QEMU vhost-user backend
+ *
+ * Copyright (C) 2018 Red Hat Inc
+ *
+ * Authors:
+ *  Marc-André Lureau <marcandre.lureau@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#ifndef QEMU_VHOST_USER_BACKEND_H
+#define QEMU_VHOST_USER_BACKEND_H
+
+#include "qom/object.h"
+#include "exec/memory.h"
+#include "qemu/option.h"
+#include "qemu/bitmap.h"
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-user.h"
+#include "chardev/char-fe.h"
+#include "io/channel.h"
+
+#define TYPE_VHOST_USER_BACKEND "vhost-user-backend"
+#define VHOST_USER_BACKEND(obj) \
+    OBJECT_CHECK(VhostUserBackend, (obj), TYPE_VHOST_USER_BACKEND)
+#define VHOST_USER_BACKEND_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(VhostUserBackendClass, (obj), TYPE_VHOST_USER_BACKEND)
+#define VHOST_USER_BACKEND_CLASS(klass) \
+    OBJECT_CLASS_CHECK(VhostUserBackendClass, (klass), TYPE_VHOST_USER_BACKEND)
+
+typedef struct VhostUserBackend VhostUserBackend;
+typedef struct VhostUserBackendClass VhostUserBackendClass;
+
+struct VhostUserBackendClass {
+    ObjectClass parent_class;
+};
+
+struct VhostUserBackend {
+    /* private */
+    Object parent;
+
+    char *cmd;
+    char *chr_name;
+
+    CharBackend chr;
+    VhostUserState vhost_user;
+    struct vhost_dev dev;
+    QIOChannel *child;
+    VirtIODevice *vdev;
+    bool started;
+    bool completed;
+};
+
+int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
+                                unsigned nvqs, Error **errp);
+void vhost_user_backend_start(VhostUserBackend *b);
+void vhost_user_backend_stop(VhostUserBackend *b);
+
+#endif
diff --git a/backends/vhost-user.c b/backends/vhost-user.c
new file mode 100644
index 0000000000..bf39c0751d
--- /dev/null
+++ b/backends/vhost-user.c
@@ -0,0 +1,244 @@
+/*
+ * QEMU vhost-user backend
+ *
+ * Copyright (C) 2018 Red Hat Inc
+ *
+ * Authors:
+ *  Marc-André Lureau <marcandre.lureau@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+
+#include "qemu/osdep.h"
+#include "hw/qdev.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "qemu/error-report.h"
+#include "qom/object_interfaces.h"
+#include "sysemu/vhost-user-backend.h"
+#include "sysemu/kvm.h"
+#include "io/channel-command.h"
+#include "hw/virtio/virtio-bus.h"
+
+static bool
+ioeventfd_enabled(void)
+{
+    return kvm_enabled() && kvm_eventfds_enabled();
+}
+
+int
+vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
+                            unsigned nvqs, Error **errp)
+{
+    int ret;
+
+    assert(!b->vdev && vdev);
+
+    if (!ioeventfd_enabled()) {
+        error_setg(errp, "vhost initialization failed: requires kvm");
+        return -1;
+    }
+
+    if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
+        return -1;
+    }
+
+    b->vdev = vdev;
+    b->dev.nvqs = nvqs;
+    b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
+
+    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "vhost initialization failed");
+        return -1;
+    }
+
+    return 0;
+}
+
+void
+vhost_user_backend_start(VhostUserBackend *b)
+{
+    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    int ret, i ;
+
+    if (b->started) {
+        return;
+    }
+
+    if (!k->set_guest_notifiers) {
+        error_report("binding does not support guest notifiers");
+        return;
+    }
+
+    ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
+    if (ret < 0) {
+        return;
+    }
+
+    ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
+    if (ret < 0) {
+        error_report("Error binding guest notifier");
+        goto err_host_notifiers;
+    }
+
+    b->dev.acked_features = b->vdev->guest_features;
+    ret = vhost_dev_start(&b->dev, b->vdev);
+    if (ret < 0) {
+        error_report("Error start vhost dev");
+        goto err_guest_notifiers;
+    }
+
+    /* guest_notifier_mask/pending not used yet, so just unmask
+     * everything here.  virtio-pci will do the right thing by
+     * enabling/disabling irqfd.
+     */
+    for (i = 0; i < b->dev.nvqs; i++) {
+        vhost_virtqueue_mask(&b->dev, b->vdev,
+                             b->dev.vq_index + i, false);
+    }
+
+    b->started = true;
+    return;
+
+err_guest_notifiers:
+    k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
+err_host_notifiers:
+    vhost_dev_disable_notifiers(&b->dev, b->vdev);
+}
+
+void
+vhost_user_backend_stop(VhostUserBackend *b)
+{
+    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    int ret = 0;
+
+    if (!b->started) {
+        return;
+    }
+
+    vhost_dev_stop(&b->dev, b->vdev);
+
+    if (k->set_guest_notifiers) {
+        ret = k->set_guest_notifiers(qbus->parent,
+                                     b->dev.nvqs, false);
+        if (ret < 0) {
+            error_report("vhost guest notifier cleanup failed: %d", ret);
+        }
+    }
+    assert(ret >= 0);
+
+    vhost_dev_disable_notifiers(&b->dev, b->vdev);
+    b->started = false;
+}
+
+static void
+vhost_user_backend_complete(UserCreatable *uc, Error **errp)
+{
+    VhostUserBackend *b = VHOST_USER_BACKEND(uc);
+    Chardev *chr;
+
+    if (!b->chr_name) {
+        error_setg(errp, "You must specificy 'chardev'.");
+        return;
+    }
+
+    chr = qemu_chr_find(b->chr_name);
+    if (chr == NULL) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Chardev '%s' not found", b->chr_name);
+        return;
+    }
+
+    if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
+        return;
+    }
+
+    b->completed = true;
+    /* could vhost_dev_init() happen here, so early vhost-user message
+     * can be exchanged */
+}
+
+static void set_chardev(Object *obj, const char *value, Error **errp)
+{
+    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
+
+    if (b->completed) {
+        error_setg(errp, QERR_PERMISSION_DENIED);
+    } else {
+        g_free(b->chr_name);
+        b->chr_name = g_strdup(value);
+    }
+}
+
+static char *get_chardev(Object *obj, Error **errp)
+{
+    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
+    Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
+
+    if (chr && chr->label) {
+        return g_strdup(chr->label);
+    }
+
+    return NULL;
+}
+
+static void vhost_user_backend_init(Object *obj)
+{
+    object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
+}
+
+static void vhost_user_backend_finalize(Object *obj)
+{
+    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
+
+    g_free(b->dev.vqs);
+    g_free(b->chr_name);
+
+    vhost_user_cleanup(&b->vhost_user);
+    qemu_chr_fe_deinit(&b->chr, true);
+
+    if (b->child) {
+        object_unref(OBJECT(b->child));
+    }
+}
+
+static bool
+vhost_user_backend_can_be_deleted(UserCreatable *uc)
+{
+    return true;
+}
+
+static void
+vhost_user_backend_class_init(ObjectClass *oc, void *data)
+{
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
+
+    ucc->complete = vhost_user_backend_complete;
+    ucc->can_be_deleted = vhost_user_backend_can_be_deleted;
+}
+
+static const TypeInfo vhost_user_backend_info = {
+    .name = TYPE_VHOST_USER_BACKEND,
+    .parent = TYPE_OBJECT,
+    .instance_size = sizeof(VhostUserBackend),
+    .instance_init = vhost_user_backend_init,
+    .instance_finalize = vhost_user_backend_finalize,
+    .class_size = sizeof(VhostUserBackendClass),
+    .class_init = vhost_user_backend_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+static void register_types(void)
+{
+    type_register_static(&vhost_user_backend_info);
+}
+
+type_init(register_types);
diff --git a/vl.c b/vl.c
index 9e4dba7f92..43012ee6a3 100644
--- a/vl.c
+++ b/vl.c
@@ -2784,7 +2784,8 @@ static bool object_create_initial(const char *type, QemuOpts *opts)
     }
 
 #if defined(CONFIG_VHOST_USER) && defined(CONFIG_LINUX)
-    if (g_str_equal(type, "cryptodev-vhost-user")) {
+    if (g_str_equal(type, "cryptodev-vhost-user") ||
+        g_str_equal(type, "vhost-user-backend")) {
         return false;
     }
 #endif
diff --git a/MAINTAINERS b/MAINTAINERS
index 16b6264412..e077fe788d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1424,6 +1424,8 @@ F: hw/*/*vhost*
 F: docs/interop/vhost-user.json
 F: docs/interop/vhost-user.txt
 F: contrib/vhost-user-*/
+F: backends/vhost-user.c
+F: include/sysemu/vhost-user-backend.h
 
 virtio
 M: Michael S. Tsirkin <mst@redhat.com>
diff --git a/backends/Makefile.objs b/backends/Makefile.objs
index 717fcbdae4..a5ec0bf907 100644
--- a/backends/Makefile.objs
+++ b/backends/Makefile.objs
@@ -12,7 +12,8 @@ common-obj-y += cryptodev-builtin.o
 ifeq ($(CONFIG_VIRTIO),y)
 common-obj-y += cryptodev-vhost.o
 common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += \
-    cryptodev-vhost-user.o
+    cryptodev-vhost-user.o \
+    vhost-user.o
 endif
 
 common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
diff --git a/qemu-options.hx b/qemu-options.hx
index 06ef1a7c5c..24315a4cda 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4203,6 +4203,26 @@ secondary:
 If you want to know the detail of above command line, you can read
 the colo-compare git log.
 
+@item -object vhost-user-backend,id=id=@var{id},chardev=@var{chardevid}
+
+Create a vhost-user-backend object that holds a connection to a
+vhost-user backend and can be referenced from virtio/vhost-user
+devices that support it.
+
+The @var{id} parameter is a unique ID that will be used to reference
+this vhost-user backend from the @option{vhost-user} device. The
+@var{chardev} parameter is the unique ID of a character device backend
+that provides the connection to the vhost-user slave process. (Since 3.2)
+
+@example
+
+ # qemu-system-x86_64 \
+   [...] \
+   -object vhost-user-backend,id=vuid,chardev=char0 \
+   -device vhost-user-input-pci,vhost-user=vuid
+   [...]
+@end example
+
 @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
 
 Creates a cryptodev backend which executes crypto opreation from
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 06/12] vhost-user: split vhost_user_read()
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (4 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 07/12] vhost-user: add vhost_user_input_get_config() Marc-André Lureau
                   ` (5 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Split vhost_user_read(), so only header can be read with
vhost_user_read_header().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
 hw/virtio/vhost-user.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index b2e1175c1e..0acf56fe96 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -210,7 +210,7 @@ static bool ioeventfd_enabled(void)
     return !kvm_enabled() || kvm_eventfds_enabled();
 }
 
-static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
+static int vhost_user_read_header(struct vhost_dev *dev, VhostUserMsg *msg)
 {
     struct vhost_user *u = dev->opaque;
     CharBackend *chr = u->user->chr;
@@ -221,7 +221,7 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
     if (r != size) {
         error_report("Failed to read msg header. Read %d instead of %d."
                      " Original request %d.", r, size, msg->hdr.request);
-        goto fail;
+        return -1;
     }
 
     /* validate received flags */
@@ -229,7 +229,21 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
         error_report("Failed to read msg header."
                 " Flags 0x%x instead of 0x%x.", msg->hdr.flags,
                 VHOST_USER_REPLY_MASK | VHOST_USER_VERSION);
-        goto fail;
+        return -1;
+    }
+
+    return 0;
+}
+
+static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
+{
+    struct vhost_user *u = dev->opaque;
+    CharBackend *chr = u->user->chr;
+    uint8_t *p = (uint8_t *) msg;
+    int r, size;
+
+    if (vhost_user_read_header(dev, msg) < 0) {
+        return -1;
     }
 
     /* validate message size is sane */
@@ -237,7 +251,7 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
         error_report("Failed to read msg header."
                 " Size %d exceeds the maximum %zu.", msg->hdr.size,
                 VHOST_USER_PAYLOAD_SIZE);
-        goto fail;
+        return -1;
     }
 
     if (msg->hdr.size) {
@@ -247,14 +261,11 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
         if (r != size) {
             error_report("Failed to read msg payload."
                          " Read %d instead of %d.", r, msg->hdr.size);
-            goto fail;
+            return -1;
         }
     }
 
     return 0;
-
-fail:
-    return -1;
 }
 
 static int process_message_reply(struct vhost_dev *dev,
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 07/12] vhost-user: add vhost_user_input_get_config()
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (5 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 06/12] vhost-user: split vhost_user_read() Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 08/12] libvhost-user-glib: export vug_source_new() Marc-André Lureau
                   ` (4 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Ask vhost user input backend the list of virtio_input_config.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
---
 contrib/libvhost-user/libvhost-user.h |  1 +
 include/hw/virtio/vhost-backend.h     |  4 ++
 hw/virtio/vhost-user.c                | 60 +++++++++++++++++++++++++++
 docs/interop/vhost-user.txt           |  8 ++++
 4 files changed, 73 insertions(+)

diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index 4aa55b4d2d..a4afbc3a46 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -91,6 +91,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_POSTCOPY_ADVISE  = 28,
     VHOST_USER_POSTCOPY_LISTEN  = 29,
     VHOST_USER_POSTCOPY_END     = 30,
+    VHOST_USER_INPUT_GET_CONFIG = 31,
     VHOST_USER_MAX
 } VhostUserRequest;
 
diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index 81283ec50f..1fca321d8a 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -12,6 +12,7 @@
 #define VHOST_BACKEND_H
 
 #include "exec/memory.h"
+#include "standard-headers/linux/virtio_input.h"
 
 typedef enum VhostBackendType {
     VHOST_BACKEND_TYPE_NONE = 0,
@@ -160,4 +161,7 @@ int vhost_backend_invalidate_device_iotlb(struct vhost_dev *dev,
 int vhost_backend_handle_iotlb_msg(struct vhost_dev *dev,
                                           struct vhost_iotlb_msg *imsg);
 
+int vhost_user_input_get_config(struct vhost_dev *dev,
+                                struct virtio_input_config **config);
+
 #endif /* VHOST_BACKEND_H */
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 0acf56fe96..272985adf2 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -89,6 +89,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_POSTCOPY_ADVISE  = 28,
     VHOST_USER_POSTCOPY_LISTEN  = 29,
     VHOST_USER_POSTCOPY_END     = 30,
+    VHOST_USER_INPUT_GET_CONFIG = 31,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -338,6 +339,65 @@ static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg,
     return 0;
 }
 
+static void *vhost_user_read_size(struct vhost_dev *dev, uint32_t size)
+{
+    struct vhost_user *u = dev->opaque;
+    CharBackend *chr = u->user->chr;
+    int r;
+    uint8_t *p = g_malloc(size);
+
+    r = qemu_chr_fe_read_all(chr, p, size);
+    if (r != size) {
+        error_report("Failed to read msg payload."
+                     " Read %d instead of %u.", r, size);
+        g_free(p);
+        return NULL;
+    }
+
+    return p;
+}
+
+int vhost_user_input_get_config(struct vhost_dev *dev,
+                                struct virtio_input_config **config)
+{
+    void *p = NULL;
+    VhostUserMsg msg = {
+        .hdr.request = VHOST_USER_INPUT_GET_CONFIG,
+        .hdr.flags = VHOST_USER_VERSION,
+    };
+
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        goto err;
+    }
+
+    if (vhost_user_read_header(dev, &msg) < 0) {
+        goto err;
+    }
+
+    if (msg.hdr.request != VHOST_USER_INPUT_GET_CONFIG) {
+        error_report("Received unexpected msg type. Expected %d received %d",
+                     VHOST_USER_INPUT_GET_CONFIG, msg.hdr.request);
+        goto err;
+    }
+
+    if (msg.hdr.size % sizeof(struct virtio_input_config)) {
+        error_report("Invalid msg size");
+        goto err;
+    }
+
+    p = vhost_user_read_size(dev, msg.hdr.size);
+    if (!p) {
+        goto err;
+    }
+
+    *config = p;
+    return msg.hdr.size / sizeof(struct virtio_input_config);
+
+err:
+    g_free(p);
+    return -1;
+}
+
 static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
                                    struct vhost_log *log)
 {
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
index cefec9ffe1..95720be81b 100644
--- a/docs/interop/vhost-user.txt
+++ b/docs/interop/vhost-user.txt
@@ -766,6 +766,14 @@ Master message types
       was previously sent.
       The value returned is an error indication; 0 is success.
 
+ * VHOST_USER_INPUT_GET_CONFIG
+      Id: 31
+      Master payload: N/A
+      Slave payload: (struct virtio_input_config)*
+
+      Ask vhost user input backend the list of virtio_input_config, in
+      host endianness.
+
 Slave message types
 -------------------
 
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 08/12] libvhost-user-glib: export vug_source_new()
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (6 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 07/12] vhost-user: add vhost_user_input_get_config() Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 09/12] libvhost-user: add vu_queue_unpop() Marc-André Lureau
                   ` (3 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Simplify the creation of FD sources for other users. This is just
convenience to avoid duplicating similar code elsewhere.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 contrib/libvhost-user/libvhost-user-glib.h |  3 +++
 contrib/libvhost-user/libvhost-user-glib.c | 11 ++++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/contrib/libvhost-user/libvhost-user-glib.h b/contrib/libvhost-user/libvhost-user-glib.h
index 6b2110b94c..d3200f3afc 100644
--- a/contrib/libvhost-user/libvhost-user-glib.h
+++ b/contrib/libvhost-user/libvhost-user-glib.h
@@ -29,4 +29,7 @@ void vug_init(VugDev *dev, int socket,
               vu_panic_cb panic, const VuDevIface *iface);
 void vug_deinit(VugDev *dev);
 
+GSource *vug_source_new(VugDev *dev, int fd, GIOCondition cond,
+                        vu_watch_cb vu_cb, gpointer data);
+
 #endif /* LIBVHOST_USER_GLIB_H */
diff --git a/contrib/libvhost-user/libvhost-user-glib.c b/contrib/libvhost-user/libvhost-user-glib.c
index 545f089587..42660a1b36 100644
--- a/contrib/libvhost-user/libvhost-user-glib.c
+++ b/contrib/libvhost-user/libvhost-user-glib.c
@@ -68,15 +68,16 @@ static GSourceFuncs vug_src_funcs = {
     NULL
 };
 
-static GSource *
-vug_source_new(VuDev *dev, int fd, GIOCondition cond,
+GSource *
+vug_source_new(VugDev *gdev, int fd, GIOCondition cond,
                vu_watch_cb vu_cb, gpointer data)
 {
+    VuDev *dev = &gdev->parent;
     GSource *gsrc;
     VugSrc *src;
     guint id;
 
-    g_assert(dev);
+    g_assert(gdev);
     g_assert(fd >= 0);
     g_assert(vu_cb);
 
@@ -106,7 +107,7 @@ set_watch(VuDev *vu_dev, int fd, int vu_evt, vu_watch_cb cb, void *pvt)
     g_assert(cb);
 
     dev = container_of(vu_dev, VugDev, parent);
-    src = vug_source_new(vu_dev, fd, vu_evt, cb, pvt);
+    src = vug_source_new(dev, fd, vu_evt, cb, pvt);
     g_hash_table_replace(dev->fdmap, GINT_TO_POINTER(fd), src);
 }
 
@@ -141,7 +142,7 @@ vug_init(VugDev *dev, int socket,
     dev->fdmap = g_hash_table_new_full(NULL, NULL, NULL,
                                        (GDestroyNotify) g_source_destroy);
 
-    dev->src = vug_source_new(&dev->parent, socket, G_IO_IN, vug_watch, NULL);
+    dev->src = vug_source_new(dev, socket, G_IO_IN, vug_watch, NULL);
 }
 
 void
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 09/12] libvhost-user: add vu_queue_unpop()
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (7 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 08/12] libvhost-user-glib: export vug_source_new() Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 10/12] Add vhost-user-input-pci Marc-André Lureau
                   ` (2 subsequent siblings)
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

vhost-user-input will make use of this function to undo some queue pop
in case the virtio queue does not have enough room.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 contrib/libvhost-user/libvhost-user.h | 14 ++++++++++++++
 contrib/libvhost-user/libvhost-user.c | 16 ++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index a4afbc3a46..6c7cbe14b6 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -459,6 +459,20 @@ void vu_queue_notify(VuDev *dev, VuVirtq *vq);
  */
 void *vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz);
 
+
+/**
+ * vu_queue_unpop:
+ * @dev: a VuDev context
+ * @vq: a VuVirtq queue
+ * @elem: The #VuVirtqElement
+ * @len: number of bytes written
+ *
+ * Pretend the most recent element wasn't popped from the virtqueue.  The next
+ * call to vu_queue_pop() will refetch the element.
+ */
+void vu_queue_unpop(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem,
+                    size_t len);
+
 /**
  * vu_queue_rewind:
  * @dev: a VuDev context
diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index fcf5014240..df72d3e440 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -1966,6 +1966,22 @@ vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
     return elem;
 }
 
+static void
+vu_queue_detach_element(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem,
+                        size_t len)
+{
+    vq->inuse--;
+    /* unmap, when DMA support is added */
+}
+
+void
+vu_queue_unpop(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem,
+               size_t len)
+{
+    vq->last_avail_idx--;
+    vu_queue_detach_element(dev, vq, elem, len);
+}
+
 bool
 vu_queue_rewind(VuDev *dev, VuVirtq *vq, unsigned int num)
 {
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 10/12] Add vhost-user-input-pci
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (8 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 09/12] libvhost-user: add vu_queue_unpop() Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 11/12] contrib: add vhost-user-input Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 12/12] RFC: add explicit can_migrate to vhost_user_backend_dev_init() Marc-André Lureau
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

Add a new virtio-input device, which connects to a vhost-user
backend. Usage:

-object vhost-user-backend,id=vuid,chardev=... \
-device vhost-user-input-pci,vhost-user=vuid

vhost-user-input is similar to virtio-input-host, it is wrapped by
vhost-user-input-pci. Instead of reading configuration directly from
an input device / evdev, it reads it over vhost-user protocol with
INPUT_GET_CONFIG message. Then vhost-user-backend takes care of
interfacing the virtio device with the backend, for the queue & events
processing.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/hw/virtio/virtio-input.h |  14 ++++
 hw/input/vhost-user-input.c      | 110 +++++++++++++++++++++++++++++++
 hw/virtio/vhost-user-input-pci.c |  53 +++++++++++++++
 MAINTAINERS                      |   1 +
 default-configs/virtio.mak       |   1 +
 hw/input/Makefile.objs           |   1 +
 hw/virtio/Makefile.objs          |   1 +
 7 files changed, 181 insertions(+)
 create mode 100644 hw/input/vhost-user-input.c
 create mode 100644 hw/virtio/vhost-user-input-pci.c

diff --git a/include/hw/virtio/virtio-input.h b/include/hw/virtio/virtio-input.h
index 054c38836f..4fca03e796 100644
--- a/include/hw/virtio/virtio-input.h
+++ b/include/hw/virtio/virtio-input.h
@@ -2,6 +2,7 @@
 #define QEMU_VIRTIO_INPUT_H
 
 #include "ui/input.h"
+#include "sysemu/vhost-user-backend.h"
 
 /* ----------------------------------------------------------------- */
 /* virtio input protocol                                             */
@@ -42,11 +43,18 @@ typedef struct virtio_input_event virtio_input_event;
 #define VIRTIO_INPUT_HOST_GET_PARENT_CLASS(obj) \
         OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_INPUT_HOST)
 
+#define TYPE_VHOST_USER_INPUT   "vhost-user-input"
+#define VHOST_USER_INPUT(obj)                              \
+    OBJECT_CHECK(VHostUserInput, (obj), TYPE_VHOST_USER_INPUT)
+#define VHOST_USER_INPUT_GET_PARENT_CLASS(obj)             \
+    OBJECT_GET_PARENT_CLASS(obj, TYPE_VHOST_USER_INPUT)
+
 typedef struct VirtIOInput VirtIOInput;
 typedef struct VirtIOInputClass VirtIOInputClass;
 typedef struct VirtIOInputConfig VirtIOInputConfig;
 typedef struct VirtIOInputHID VirtIOInputHID;
 typedef struct VirtIOInputHost VirtIOInputHost;
+typedef struct VHostUserInput VHostUserInput;
 
 struct VirtIOInputConfig {
     virtio_input_config               config;
@@ -98,6 +106,12 @@ struct VirtIOInputHost {
     int                               fd;
 };
 
+struct VHostUserInput {
+    VirtIOInput                       parent_obj;
+
+    VhostUserBackend                  *vhost;
+};
+
 void virtio_input_send(VirtIOInput *vinput, virtio_input_event *event);
 void virtio_input_init_config(VirtIOInput *vinput,
                               virtio_input_config *config);
diff --git a/hw/input/vhost-user-input.c b/hw/input/vhost-user-input.c
new file mode 100644
index 0000000000..ef1b23a8b2
--- /dev/null
+++ b/hw/input/vhost-user-input.c
@@ -0,0 +1,110 @@
+/*
+ * 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 "qapi/error.h"
+#include "qemu-common.h"
+
+#include "hw/qdev.h"
+#include "hw/virtio/virtio-input.h"
+
+static void vhost_input_realize(DeviceState *dev, Error **errp)
+{
+    VHostUserInput *vhi = VHOST_USER_INPUT(dev);
+    VirtIOInput *vinput = VIRTIO_INPUT(dev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    virtio_input_config *config;
+    int i, ret;
+
+    if (!vhi->vhost) {
+        error_setg(errp, "'vhost-user' property is required");
+        return;
+    }
+
+    if (vhost_user_backend_dev_init(vhi->vhost, vdev, 2, errp) == -1) {
+        return;
+    }
+
+    ret = vhost_user_input_get_config(&vhi->vhost->dev, &config);
+    if (ret < 0) {
+        error_setg(errp, "failed to get input config");
+        return;
+    }
+    for (i = 0; i < ret; i++) {
+        virtio_input_add_config(vinput, &config[i]);
+    }
+    g_free(config);
+}
+
+static void vhost_input_change_active(VirtIOInput *vinput)
+{
+    VHostUserInput *vhi = VHOST_USER_INPUT(vinput);
+
+    if (vinput->active) {
+        vhost_user_backend_start(vhi->vhost);
+    } else {
+        vhost_user_backend_stop(vhi->vhost);
+    }
+}
+
+static const VMStateDescription vmstate_vhost_input = {
+    .name = "vhost-user-input",
+    .unmigratable = 1,
+};
+
+static void vhost_input_class_init(ObjectClass *klass, void *data)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd           = &vmstate_vhost_input;
+    vic->realize       = vhost_input_realize;
+    vic->change_active = vhost_input_change_active;
+}
+
+static void vhost_input_is_busy(const Object *obj, const char *name,
+                                Object *val, Error **errp)
+{
+    VHostUserInput *vhi = VHOST_USER_INPUT(obj);
+
+    if (vhi->vhost) {
+        error_setg(errp, "can't use already busy vhost-user");
+    } else {
+        qdev_prop_allow_set_link_before_realize(obj, name, val, errp);
+    }
+}
+
+static void vhost_input_init(Object *obj)
+{
+    VHostUserInput *vhi = VHOST_USER_INPUT(obj);
+    VirtIOInput *vinput = VIRTIO_INPUT(obj);
+    struct virtio_input_config vhost_input_config[] = { { /* empty list */ } };
+
+    virtio_input_init_config(vinput, vhost_input_config);
+
+    object_property_add_link(obj, "vhost-user", TYPE_VHOST_USER_BACKEND,
+                             (Object **)&vhi->vhost,
+                             vhost_input_is_busy,
+                             OBJ_PROP_LINK_STRONG,
+                             &error_abort);
+}
+
+static const TypeInfo vhost_input_info = {
+    .name          = TYPE_VHOST_USER_INPUT,
+    .parent        = TYPE_VIRTIO_INPUT,
+    .instance_size = sizeof(VHostUserInput),
+    .instance_init = vhost_input_init,
+    .class_init    = vhost_input_class_init,
+};
+
+/* ----------------------------------------------------------------- */
+
+static void vhost_input_register_types(void)
+{
+    type_register_static(&vhost_input_info);
+}
+
+type_init(vhost_input_register_types)
diff --git a/hw/virtio/vhost-user-input-pci.c b/hw/virtio/vhost-user-input-pci.c
new file mode 100644
index 0000000000..cd817f505d
--- /dev/null
+++ b/hw/virtio/vhost-user-input-pci.c
@@ -0,0 +1,53 @@
+/*
+ * This work is licensed under the terms of the GNU LGPL, version 2 or
+ * later.  See the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-input.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "virtio-pci.h"
+
+typedef struct VHostUserInputPCI VHostUserInputPCI;
+
+#define TYPE_VHOST_USER_INPUT_PCI "vhost-user-input-pci-base"
+
+#define VHOST_USER_INPUT_PCI(obj) \
+    OBJECT_CHECK(VHostUserInputPCI, (obj), TYPE_VHOST_USER_INPUT_PCI)
+
+struct VHostUserInputPCI {
+    VirtIOPCIProxy parent_obj;
+    VHostUserInput vhi;
+};
+
+static void vhost_user_input_pci_instance_init(Object *obj)
+{
+    VHostUserInputPCI *dev = VHOST_USER_INPUT_PCI(obj);
+
+    virtio_instance_init_common(obj, &dev->vhi, sizeof(dev->vhi),
+                                TYPE_VHOST_USER_INPUT);
+
+    object_property_add_alias(obj, "vhost-user",
+                              OBJECT(&dev->vhi), "vhost-user",
+                              &error_abort);
+}
+
+static const VirtioPCIDeviceTypeInfo vhost_user_input_pci_info = {
+    .base_name = TYPE_VHOST_USER_INPUT_PCI,
+    .generic_name = "vhost-user-input-pci",
+    .transitional_name = "vhost-user-input-pci-transitional",
+    .non_transitional_name = "vhost-user-input-pci-non-transitional",
+    .parent = TYPE_VIRTIO_INPUT_PCI,
+    .instance_size = sizeof(VHostUserInputPCI),
+    .instance_init = vhost_user_input_pci_instance_init,
+};
+
+static void vhost_user_input_pci_register(void)
+{
+    virtio_pci_types_register(&vhost_user_input_pci_info);
+}
+
+type_init(vhost_user_input_pci_register)
diff --git a/MAINTAINERS b/MAINTAINERS
index e077fe788d..5dfc9531bf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1467,6 +1467,7 @@ L: qemu-s390x@nongnu.org
 virtio-input
 M: Gerd Hoffmann <kraxel@redhat.com>
 S: Maintained
+F: hw/input/vhost-user-input.c
 F: hw/input/virtio-input*.c
 F: include/hw/virtio/virtio-input.h
 
diff --git a/default-configs/virtio.mak b/default-configs/virtio.mak
index ecb4420e74..5f5266ef8b 100644
--- a/default-configs/virtio.mak
+++ b/default-configs/virtio.mak
@@ -13,3 +13,4 @@ CONFIG_SCSI=y
 CONFIG_VIRTIO_SCSI=y
 CONFIG_VIRTIO_SERIAL=y
 CONFIG_VIRTIO_INPUT_HOST=$(CONFIG_LINUX)
+CONFIG_VHOST_USER_INPUT=$(call land,$(CONFIG_VHOST_USER),$(CONFIG_VIRTIO_INPUT))
diff --git a/hw/input/Makefile.objs b/hw/input/Makefile.objs
index c8b00f71ec..9511e3102f 100644
--- a/hw/input/Makefile.objs
+++ b/hw/input/Makefile.objs
@@ -11,6 +11,7 @@ common-obj-$(CONFIG_VIRTIO_INPUT) += virtio-input.o
 common-obj-$(CONFIG_VIRTIO_INPUT) += virtio-input-hid.o
 ifeq ($(CONFIG_LINUX),y)
 common-obj-$(CONFIG_VIRTIO_INPUT) += virtio-input-host.o
+common-obj-$(CONFIG_VHOST_USER_INPUT) += vhost-user-input.o
 endif
 
 obj-$(CONFIG_MILKYMIST) += milkymist-softusb.o
diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
index d335dd0a6a..7462051ba3 100644
--- a/hw/virtio/Makefile.objs
+++ b/hw/virtio/Makefile.objs
@@ -14,6 +14,7 @@ obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock.o
 ifeq ($(CONFIG_VIRTIO_PCI),y)
 obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-pci.o
 obj-$(CONFIG_VHOST_USER_BLK) += vhost-user-blk-pci.o
+obj-$(CONFIG_VHOST_USER_INPUT) += vhost-user-input-pci.o
 obj-$(CONFIG_VHOST_USER_SCSI) += vhost-user-scsi-pci.o
 obj-$(CONFIG_VHOST_SCSI) += vhost-scsi-pci.o
 obj-$(CONFIG_VIRTIO_INPUT_HOST) += virtio-input-host-pci.o
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 11/12] contrib: add vhost-user-input
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (9 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 10/12] Add vhost-user-input-pci Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 12/12] RFC: add explicit can_migrate to vhost_user_backend_dev_init() Marc-André Lureau
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, 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-backend object, for example via a unix socket:

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

$ qemu ... -chardev socket,id=vuic,path=/tmp/vui.sock
  -object vhost-user-backend,chardev=vuic

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 contrib/vhost-user-input/main.c        | 398 +++++++++++++++++++++++++
 MAINTAINERS                            |   1 +
 Makefile                               |   3 +
 Makefile.objs                          |   1 +
 configure                              |   3 +
 contrib/vhost-user-input/Makefile.objs |   1 +
 6 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..bef44f163d
--- /dev/null
+++ b/contrib/vhost-user-input/main.c
@@ -0,0 +1,398 @@
+/*
+ * 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 "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;
+    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 int
+vi_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
+{
+    VuInput *vi = container_of(dev, VuInput, dev.parent);
+
+    switch (vmsg->request) {
+    case VHOST_USER_INPUT_GET_CONFIG:
+        vmsg->size = vi->config->len * sizeof(virtio_input_config);
+        vmsg->data = g_memdup(vi->config->data, vmsg->size);
+        *do_reply = true;
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+static const VuDevIface vuiface = {
+    .queue_set_started = vi_queue_set_started,
+    .process_msg = vi_process_msg,
+};
+
+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 int unix_sock_new(char *path)
+{
+    int sock;
+    struct sockaddr_un un;
+    size_t len;
+
+    sock = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (sock <= 0) {
+        perror("socket");
+        return -1;
+    }
+
+    un.sun_family = AF_UNIX;
+    snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
+    len = sizeof(un.sun_family) + strlen(un.sun_path);
+
+    unlink(path);
+    if (bind(sock, (struct sockaddr *)&un, len) < 0) {
+        perror("bind");
+        goto fail;
+    }
+
+    if (listen(sock, 1) < 0) {
+        perror("listen");
+        goto fail;
+    }
+
+    return sock;
+
+fail:
+    close(sock);
+
+    return -1;
+}
+
+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_sock_new(opt_socket_path);
+        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 5dfc9531bf..8bee393026 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1470,6 +1470,7 @@ 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 3658310b95..6cb2a88d66 100644
--- a/Makefile
+++ b/Makefile
@@ -369,6 +369,7 @@ dummy := $(call unnest-vars,, \
                 libvhost-user-obj-y \
                 vhost-user-scsi-obj-y \
                 vhost-user-blk-obj-y \
+                vhost-user-input-obj-y \
                 qga-vss-dll-obj-y \
                 block-obj-y \
                 block-obj-m \
@@ -588,6 +589,8 @@ vhost-user-blk$(EXESUF): $(vhost-user-blk-obj-y) libvhost-user.a
 rdmacm-mux$(EXESUF): LIBS += "-libumad"
 rdmacm-mux$(EXESUF): $(rdmacm-mux-obj-y) $(COMMON_LDADDS)
 	$(call LINK, $^)
+vhost-user-input$(EXESUF): $(vhost-user-input-obj-y) libvhost-user.a libqemuutil.a
+	$(call LINK, $^)
 
 module_block.h: $(SRC_PATH)/scripts/modules/module_block.py config-host.mak
 	$(call quiet-command,$(PYTHON) $< $@ \
diff --git a/Makefile.objs b/Makefile.objs
index 67a054b08a..c229ac3bef 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -134,6 +134,7 @@ 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/configure b/configure
index 558170cb64..d67b90683f 100755
--- a/configure
+++ b/configure
@@ -5793,6 +5793,9 @@ if test "$want_tools" = "yes" ; then
   if [ "$curl" = "yes" ]; then
       tools="elf2dmp\$(EXESUF) $tools"
   fi
+  if [ "$vhost_user" = "yes" ] && [ "$linux" = "yes" ] ; then
+    tools="vhost-user-input\$(EXESUF) $tools"
+  fi
 fi
 if test "$softmmu" = yes ; then
   if test "$linux" = yes; then
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
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [Qemu-devel] [PATCH v2 12/12] RFC: add explicit can_migrate to vhost_user_backend_dev_init()
  2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
                   ` (10 preceding siblings ...)
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 11/12] contrib: add vhost-user-input Marc-André Lureau
@ 2019-02-07 16:54 ` Marc-André Lureau
  11 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 16:54 UTC (permalink / raw)
  To: qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin, Marc-André Lureau

In general, there is not much support for migrating a vhost-user slave
process. Many virtio devices however implement vmsd, and the
vhost-user instances (as child objects) may be migrated.

Since there is no other support at this point, the slave is assumed to
be state less (outside of VM state), or using a migration method
outside of qemu migration stream.

Since this is not well specified, add a common blocker for the
VhostUserBackend users (vhost-user-input and upcoming gpu will use
it).

RFC since I am not sure that's what Michael had in mind when
requesting such blocker.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/sysemu/vhost-user-backend.h | 2 +-
 backends/vhost-user.c               | 7 ++++++-
 hw/input/vhost-user-input.c         | 2 +-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/sysemu/vhost-user-backend.h b/include/sysemu/vhost-user-backend.h
index 60f811cae7..feb331288f 100644
--- a/include/sysemu/vhost-user-backend.h
+++ b/include/sysemu/vhost-user-backend.h
@@ -53,7 +53,7 @@ struct VhostUserBackend {
 };
 
 int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
-                                unsigned nvqs, Error **errp);
+                                unsigned nvqs, bool can_migrate, Error **errp);
 void vhost_user_backend_start(VhostUserBackend *b);
 void vhost_user_backend_stop(VhostUserBackend *b);
 
diff --git a/backends/vhost-user.c b/backends/vhost-user.c
index bf39c0751d..4e0af8952a 100644
--- a/backends/vhost-user.c
+++ b/backends/vhost-user.c
@@ -30,7 +30,7 @@ ioeventfd_enabled(void)
 
 int
 vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
-                            unsigned nvqs, Error **errp)
+                            unsigned nvqs, bool can_migrate, Error **errp)
 {
     int ret;
 
@@ -49,6 +49,11 @@ vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
     b->dev.nvqs = nvqs;
     b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
 
+    if (!can_migrate && !b->dev.migration_blocker) {
+        error_setg(&b->dev.migration_blocker,
+                   "Migration disabled: vhost-user device can't migrate");
+    }
+
     ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "vhost initialization failed");
diff --git a/hw/input/vhost-user-input.c b/hw/input/vhost-user-input.c
index ef1b23a8b2..360a2ff618 100644
--- a/hw/input/vhost-user-input.c
+++ b/hw/input/vhost-user-input.c
@@ -24,7 +24,7 @@ static void vhost_input_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    if (vhost_user_backend_dev_init(vhi->vhost, vdev, 2, errp) == -1) {
+    if (vhost_user_backend_dev_init(vhi->vhost, vdev, 2, false, errp) == -1) {
         return;
     }
 
-- 
2.20.1.519.g8feddda32c

^ permalink raw reply related	[flat|nested] 19+ messages in thread

* Re: [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend Marc-André Lureau
@ 2019-02-07 17:36   ` Michael S. Tsirkin
  2019-02-07 18:29     ` Marc-André Lureau
  0 siblings, 1 reply; 19+ messages in thread
From: Michael S. Tsirkin @ 2019-02-07 17:36 UTC (permalink / raw)
  To: Marc-André Lureau; +Cc: qemu-devel, Gerd Hoffmann, Paolo Bonzini

On Thu, Feb 07, 2019 at 05:54:42PM +0100, Marc-André Lureau wrote:
> Create a vhost-user-backend object that holds a connection to a
> vhost-user backend and can be referenced from virtio devices that
> support it. See later patches for input & gpu usage.
> 
> A chardev must be specified to communicate with the vhost-user
> backend, ex: -chardev socket,id=char0,path=/tmp/foo.sock -object
> vhost-user-backend,id=vuid,chardev=char0.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

So having an internal object that can maintain runtime state
might be a good idea. However I don't yet really see
what kind of property could such an object have that
the char device couldn't.

I could see value if user did not have to specify
a completely separate device.

Consider:

-chardev socket,id=char0,path=/tmp/foo.sock 
-object vhost-user-backend,id=vuid,chardev=char0
-device vhost-user-input-pci,vhost-user=vuid


There's 3 times vhost-user here, and nothing actually says it's
virtio-input, that is implicit :(

So I feel CLI needs to change.  But I do think the idea of
an object in between does have some potential.

Consider virtio net which now has modern, legacy and transitional
variants. How is vhost-user-X type going to scale there?
That's a problem worth solving IMHO.

Also, there's a problem right now in that if backend
connects before device is available (e.g. because we
want to hotplug the device later) then we can not
validate the backend. So it will fail way later.
I am not sure how much do we want to validate,
but if e.g. it's a different device type completely,
that seems like a reasonable thing to validate.

So I do see potential in a vhost user backend object
but then it has to encapsulate all vhost user things,
such that you can connect a virtio device to a
vhost user object.





> ---
>  include/sysemu/vhost-user-backend.h |  60 +++++++
>  backends/vhost-user.c               | 244 ++++++++++++++++++++++++++++
>  vl.c                                |   3 +-
>  MAINTAINERS                         |   2 +
>  backends/Makefile.objs              |   3 +-
>  qemu-options.hx                     |  20 +++
>  6 files changed, 330 insertions(+), 2 deletions(-)
>  create mode 100644 include/sysemu/vhost-user-backend.h
>  create mode 100644 backends/vhost-user.c
> 
> diff --git a/include/sysemu/vhost-user-backend.h b/include/sysemu/vhost-user-backend.h
> new file mode 100644
> index 0000000000..60f811cae7
> --- /dev/null
> +++ b/include/sysemu/vhost-user-backend.h
> @@ -0,0 +1,60 @@
> +/*
> + * QEMU vhost-user backend
> + *
> + * Copyright (C) 2018 Red Hat Inc
> + *
> + * Authors:
> + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +#ifndef QEMU_VHOST_USER_BACKEND_H
> +#define QEMU_VHOST_USER_BACKEND_H
> +
> +#include "qom/object.h"
> +#include "exec/memory.h"
> +#include "qemu/option.h"
> +#include "qemu/bitmap.h"
> +#include "hw/virtio/vhost.h"
> +#include "hw/virtio/vhost-user.h"
> +#include "chardev/char-fe.h"
> +#include "io/channel.h"
> +
> +#define TYPE_VHOST_USER_BACKEND "vhost-user-backend"
> +#define VHOST_USER_BACKEND(obj) \
> +    OBJECT_CHECK(VhostUserBackend, (obj), TYPE_VHOST_USER_BACKEND)
> +#define VHOST_USER_BACKEND_GET_CLASS(obj) \
> +    OBJECT_GET_CLASS(VhostUserBackendClass, (obj), TYPE_VHOST_USER_BACKEND)
> +#define VHOST_USER_BACKEND_CLASS(klass) \
> +    OBJECT_CLASS_CHECK(VhostUserBackendClass, (klass), TYPE_VHOST_USER_BACKEND)
> +
> +typedef struct VhostUserBackend VhostUserBackend;
> +typedef struct VhostUserBackendClass VhostUserBackendClass;
> +
> +struct VhostUserBackendClass {
> +    ObjectClass parent_class;
> +};
> +
> +struct VhostUserBackend {
> +    /* private */
> +    Object parent;
> +
> +    char *cmd;
> +    char *chr_name;
> +
> +    CharBackend chr;
> +    VhostUserState vhost_user;
> +    struct vhost_dev dev;
> +    QIOChannel *child;
> +    VirtIODevice *vdev;
> +    bool started;
> +    bool completed;
> +};
> +
> +int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> +                                unsigned nvqs, Error **errp);
> +void vhost_user_backend_start(VhostUserBackend *b);
> +void vhost_user_backend_stop(VhostUserBackend *b);
> +
> +#endif
> diff --git a/backends/vhost-user.c b/backends/vhost-user.c
> new file mode 100644
> index 0000000000..bf39c0751d
> --- /dev/null
> +++ b/backends/vhost-user.c
> @@ -0,0 +1,244 @@
> +/*
> + * QEMU vhost-user backend
> + *
> + * Copyright (C) 2018 Red Hat Inc
> + *
> + * Authors:
> + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +
> +#include "qemu/osdep.h"
> +#include "hw/qdev.h"
> +#include "qapi/error.h"
> +#include "qapi/qmp/qerror.h"
> +#include "qemu/error-report.h"
> +#include "qom/object_interfaces.h"
> +#include "sysemu/vhost-user-backend.h"
> +#include "sysemu/kvm.h"
> +#include "io/channel-command.h"
> +#include "hw/virtio/virtio-bus.h"
> +
> +static bool
> +ioeventfd_enabled(void)
> +{
> +    return kvm_enabled() && kvm_eventfds_enabled();
> +}
> +
> +int
> +vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> +                            unsigned nvqs, Error **errp)
> +{
> +    int ret;
> +
> +    assert(!b->vdev && vdev);
> +
> +    if (!ioeventfd_enabled()) {
> +        error_setg(errp, "vhost initialization failed: requires kvm");
> +        return -1;
> +    }
> +
> +    if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
> +        return -1;
> +    }
> +
> +    b->vdev = vdev;
> +    b->dev.nvqs = nvqs;
> +    b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
> +
> +    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
> +    if (ret < 0) {
> +        error_setg_errno(errp, -ret, "vhost initialization failed");
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +void
> +vhost_user_backend_start(VhostUserBackend *b)
> +{
> +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> +    int ret, i ;
> +
> +    if (b->started) {
> +        return;
> +    }
> +
> +    if (!k->set_guest_notifiers) {
> +        error_report("binding does not support guest notifiers");
> +        return;
> +    }
> +
> +    ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
> +    if (ret < 0) {
> +        return;
> +    }
> +
> +    ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
> +    if (ret < 0) {
> +        error_report("Error binding guest notifier");
> +        goto err_host_notifiers;
> +    }
> +
> +    b->dev.acked_features = b->vdev->guest_features;
> +    ret = vhost_dev_start(&b->dev, b->vdev);
> +    if (ret < 0) {
> +        error_report("Error start vhost dev");
> +        goto err_guest_notifiers;
> +    }
> +
> +    /* guest_notifier_mask/pending not used yet, so just unmask
> +     * everything here.  virtio-pci will do the right thing by
> +     * enabling/disabling irqfd.
> +     */
> +    for (i = 0; i < b->dev.nvqs; i++) {
> +        vhost_virtqueue_mask(&b->dev, b->vdev,
> +                             b->dev.vq_index + i, false);
> +    }
> +
> +    b->started = true;
> +    return;
> +
> +err_guest_notifiers:
> +    k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
> +err_host_notifiers:
> +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> +}
> +
> +void
> +vhost_user_backend_stop(VhostUserBackend *b)
> +{
> +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> +    int ret = 0;
> +
> +    if (!b->started) {
> +        return;
> +    }
> +
> +    vhost_dev_stop(&b->dev, b->vdev);
> +
> +    if (k->set_guest_notifiers) {
> +        ret = k->set_guest_notifiers(qbus->parent,
> +                                     b->dev.nvqs, false);
> +        if (ret < 0) {
> +            error_report("vhost guest notifier cleanup failed: %d", ret);
> +        }
> +    }
> +    assert(ret >= 0);
> +
> +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> +    b->started = false;
> +}
> +
> +static void
> +vhost_user_backend_complete(UserCreatable *uc, Error **errp)
> +{
> +    VhostUserBackend *b = VHOST_USER_BACKEND(uc);
> +    Chardev *chr;
> +
> +    if (!b->chr_name) {
> +        error_setg(errp, "You must specificy 'chardev'.");
> +        return;
> +    }
> +
> +    chr = qemu_chr_find(b->chr_name);
> +    if (chr == NULL) {
> +        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> +                  "Chardev '%s' not found", b->chr_name);
> +        return;
> +    }
> +
> +    if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
> +        return;
> +    }
> +
> +    b->completed = true;
> +    /* could vhost_dev_init() happen here, so early vhost-user message
> +     * can be exchanged */
> +}
> +
> +static void set_chardev(Object *obj, const char *value, Error **errp)
> +{
> +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> +
> +    if (b->completed) {
> +        error_setg(errp, QERR_PERMISSION_DENIED);
> +    } else {
> +        g_free(b->chr_name);
> +        b->chr_name = g_strdup(value);
> +    }
> +}
> +
> +static char *get_chardev(Object *obj, Error **errp)
> +{
> +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> +    Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
> +
> +    if (chr && chr->label) {
> +        return g_strdup(chr->label);
> +    }
> +
> +    return NULL;
> +}
> +
> +static void vhost_user_backend_init(Object *obj)
> +{
> +    object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
> +}
> +
> +static void vhost_user_backend_finalize(Object *obj)
> +{
> +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> +
> +    g_free(b->dev.vqs);
> +    g_free(b->chr_name);
> +
> +    vhost_user_cleanup(&b->vhost_user);
> +    qemu_chr_fe_deinit(&b->chr, true);
> +
> +    if (b->child) {
> +        object_unref(OBJECT(b->child));
> +    }
> +}
> +
> +static bool
> +vhost_user_backend_can_be_deleted(UserCreatable *uc)
> +{
> +    return true;
> +}
> +
> +static void
> +vhost_user_backend_class_init(ObjectClass *oc, void *data)
> +{
> +    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
> +
> +    ucc->complete = vhost_user_backend_complete;
> +    ucc->can_be_deleted = vhost_user_backend_can_be_deleted;
> +}
> +
> +static const TypeInfo vhost_user_backend_info = {
> +    .name = TYPE_VHOST_USER_BACKEND,
> +    .parent = TYPE_OBJECT,
> +    .instance_size = sizeof(VhostUserBackend),
> +    .instance_init = vhost_user_backend_init,
> +    .instance_finalize = vhost_user_backend_finalize,
> +    .class_size = sizeof(VhostUserBackendClass),
> +    .class_init = vhost_user_backend_class_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_USER_CREATABLE },
> +        { }
> +    }
> +};
> +
> +static void register_types(void)
> +{
> +    type_register_static(&vhost_user_backend_info);
> +}
> +
> +type_init(register_types);
> diff --git a/vl.c b/vl.c
> index 9e4dba7f92..43012ee6a3 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2784,7 +2784,8 @@ static bool object_create_initial(const char *type, QemuOpts *opts)
>      }
>  
>  #if defined(CONFIG_VHOST_USER) && defined(CONFIG_LINUX)
> -    if (g_str_equal(type, "cryptodev-vhost-user")) {
> +    if (g_str_equal(type, "cryptodev-vhost-user") ||
> +        g_str_equal(type, "vhost-user-backend")) {
>          return false;
>      }
>  #endif
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 16b6264412..e077fe788d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1424,6 +1424,8 @@ F: hw/*/*vhost*
>  F: docs/interop/vhost-user.json
>  F: docs/interop/vhost-user.txt
>  F: contrib/vhost-user-*/
> +F: backends/vhost-user.c
> +F: include/sysemu/vhost-user-backend.h
>  
>  virtio
>  M: Michael S. Tsirkin <mst@redhat.com>
> diff --git a/backends/Makefile.objs b/backends/Makefile.objs
> index 717fcbdae4..a5ec0bf907 100644
> --- a/backends/Makefile.objs
> +++ b/backends/Makefile.objs
> @@ -12,7 +12,8 @@ common-obj-y += cryptodev-builtin.o
>  ifeq ($(CONFIG_VIRTIO),y)
>  common-obj-y += cryptodev-vhost.o
>  common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += \
> -    cryptodev-vhost-user.o
> +    cryptodev-vhost-user.o \
> +    vhost-user.o
>  endif
>  
>  common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 06ef1a7c5c..24315a4cda 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4203,6 +4203,26 @@ secondary:
>  If you want to know the detail of above command line, you can read
>  the colo-compare git log.
>  
> +@item -object vhost-user-backend,id=id=@var{id},chardev=@var{chardevid}
> +
> +Create a vhost-user-backend object that holds a connection to a
> +vhost-user backend and can be referenced from virtio/vhost-user
> +devices that support it.
> +
> +The @var{id} parameter is a unique ID that will be used to reference
> +this vhost-user backend from the @option{vhost-user} device. The
> +@var{chardev} parameter is the unique ID of a character device backend
> +that provides the connection to the vhost-user slave process. (Since 3.2)
> +
> +@example
> +
> + # qemu-system-x86_64 \
> +   [...] \
> +   -object vhost-user-backend,id=vuid,chardev=char0 \
> +   -device vhost-user-input-pci,vhost-user=vuid
> +   [...]
> +@end example
> +
>  @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
>  
>  Creates a cryptodev backend which executes crypto opreation from
> -- 
> 2.20.1.519.g8feddda32c

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends
  2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends Marc-André Lureau
@ 2019-02-07 17:42   ` Eric Blake
  2019-02-07 18:45     ` Marc-André Lureau
  0 siblings, 1 reply; 19+ messages in thread
From: Eric Blake @ 2019-02-07 17:42 UTC (permalink / raw)
  To: Marc-André Lureau, qemu-devel; +Cc: Gerd Hoffmann, Michael S. Tsirkin

[-- Attachment #1: Type: text/plain, Size: 4103 bytes --]

On 2/7/19 10:54 AM, Marc-André Lureau wrote:
> As discussed during "[PATCH v4 00/29] vhost-user for input & GPU"
> review, let's define a common set of backend conventions to help with
> management layer implementation, and interoperability.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  MAINTAINERS                  |   1 +
>  docs/interop/vhost-user.json | 219 +++++++++++++++++++++++++++++++++++
>  docs/interop/vhost-user.txt  | 101 +++++++++++++++-
>  3 files changed, 319 insertions(+), 2 deletions(-)
>  create mode 100644 docs/interop/vhost-user.json

> +##
> +# @VHostUserBackendType:
> +#
> +# List the various vhost user backend types.
> +#
> +# @net: virtio net
> +# @block: virtio block
> +# @console: virtio console
> +# @rng: virtio rng
> +# @balloon: virtio balloon
> +# @rpmsg: virtio remote processor messaging
> +# @scsi: virtio scsi
> +# @9p: 9p virtio console
> +# @rproc-serial: virtio remoteproc serial link
> +# @caif: virtio caif
> +# @gpu: virtio gpu
> +# @input: virtio input
> +# @vsock: virtio vsock transport
> +# @crypto: virtio crypto
> +#
> +# Since: 3.2

s/3.2/4.0/g in your patch series

> +##
> +{
> +  'enum': 'VHostUserBackendType',
> +  'data': [ 'net', 'block', 'console', 'rng', 'balloon', 'rpmsg',
> +            'scsi', '9p', 'rproc-serial', 'caif', 'gpu', 'input', 'vsock',
> +            'crypto' ]
> +}

Worth alphabetizing? Not a strong requirement, though, if this order
makes more sense.


> +#
> +# Top-down, the list of directories goes from general to specific.
> +#
> +# Management software should build a list of files from all three
> +# locations, then sort the list by filename (i.e., last pathname

perhaps s/filename/basename/

> +# component). Management software should choose the first JSON file on
> +# the sorted list that matches the search criteria. If a more specific
> +# directory has a file with same name as a less specific directory, then
> +# the file in the more specific directory takes effect. If the more
> +# specific file is zero length, it hides the less specific one.
> +#

> +++ b/docs/interop/vhost-user.txt
> @@ -17,8 +17,13 @@ The protocol defines 2 sides of the communication, master and slave. Master is
>  the application that shares its virtqueues, in our case QEMU. Slave is the
>  consumer of the virtqueues.
>  
> -In the current implementation QEMU is the Master, and the Slave is intended to
> -be a software Ethernet switch running in user space, such as Snabbswitch.
> +In the current implementation QEMU is the Master, and the Slave is the
> +external process consuming the virtio queues, for example a software
> +Ethernet switch running in user space, such as Snabbswitch, or a block

Is 'slirp' any better than 'Snabbswitch' as a demonstration of
user-space networking?

> +device backend processing read & write to a virtual disk. In order to
> +facilitate interoperability between various backend implementations,
> +it is recommended to follow the "Backend program conventions"
> +described in this document.
>  

> +
> +The backend program must end (as quickly and cleanly as possible) when
> +the SIGTERM signal is received. Eventually, it may be SIGKILL by the

s/be/receive/

> +management layer after a few seconds.
> +
> +The following command line options have an expected behaviour. They
> +are mandatory, unless explicitly said differently:
> +
> +* --socket-path=PATH
> +
> +This option specify the location of the vhost-user Unix domain socket.
> +It is incompatible with --fd.
> +
> +* --fd=FDNUM
> +
> +When this argument is given, the backend program is started with the
> +vhost-user socket as file descriptor FDNUM. It is incompatible with
> +--socket-path.

Do we also want to require support for systemd-style
LISTEN_PID/LISTEN_FDS socket activation?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend
  2019-02-07 17:36   ` Michael S. Tsirkin
@ 2019-02-07 18:29     ` Marc-André Lureau
  2019-02-07 19:18       ` Michael S. Tsirkin
  0 siblings, 1 reply; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 18:29 UTC (permalink / raw)
  To: Michael S. Tsirkin; +Cc: qemu-devel, Gerd Hoffmann, Paolo Bonzini

Hi

On Thu, Feb 7, 2019 at 6:36 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Feb 07, 2019 at 05:54:42PM +0100, Marc-André Lureau wrote:
> > Create a vhost-user-backend object that holds a connection to a
> > vhost-user backend and can be referenced from virtio devices that
> > support it. See later patches for input & gpu usage.
> >
> > A chardev must be specified to communicate with the vhost-user
> > backend, ex: -chardev socket,id=char0,path=/tmp/foo.sock -object
> > vhost-user-backend,id=vuid,chardev=char0.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> So having an internal object that can maintain runtime state
> might be a good idea. However I don't yet really see
> what kind of property could such an object have that
> the char device couldn't.>
> I could see value if user did not have to specify
> a completely separate device.
>
> Consider:
>
> -chardev socket,id=char0,path=/tmp/foo.sock
> -object vhost-user-backend,id=vuid,chardev=char0
> -device vhost-user-input-pci,vhost-user=vuid
>
>
> There's 3 times vhost-user here, and nothing actually says it's
> virtio-input, that is implicit :(
>
> So I feel CLI needs to change.  But I do think the idea of
> an object in between does have some potential.

Ok, I dropped the -object from CLI. It can be added later if needed.

It makes some sense imho to wrap all the configuration/documentation
in a backend object. But since we have only chardev= now (cmd= is
being postponed), and I can only speculate on what could come next,
let's just have it as internal helper for now.

I'll adjust/resend this series, this will also impact the -gpu and
libvirt series.

>
> Consider virtio net which now has modern, legacy and transitional
> variants. How is vhost-user-X type going to scale there?
> That's a problem worth solving IMHO.
>
> Also, there's a problem right now in that if backend
> connects before device is available (e.g. because we
> want to hotplug the device later) then we can not
> validate the backend. So it will fail way later.
> I am not sure how much do we want to validate,
> but if e.g. it's a different device type completely,
> that seems like a reasonable thing to validate.
>
> So I do see potential in a vhost user backend object
> but then it has to encapsulate all vhost user things,
> such that you can connect a virtio device to a
> vhost user object.
>
>
>
>
>
> > ---
> >  include/sysemu/vhost-user-backend.h |  60 +++++++
> >  backends/vhost-user.c               | 244 ++++++++++++++++++++++++++++
> >  vl.c                                |   3 +-
> >  MAINTAINERS                         |   2 +
> >  backends/Makefile.objs              |   3 +-
> >  qemu-options.hx                     |  20 +++
> >  6 files changed, 330 insertions(+), 2 deletions(-)
> >  create mode 100644 include/sysemu/vhost-user-backend.h
> >  create mode 100644 backends/vhost-user.c
> >
> > diff --git a/include/sysemu/vhost-user-backend.h b/include/sysemu/vhost-user-backend.h
> > new file mode 100644
> > index 0000000000..60f811cae7
> > --- /dev/null
> > +++ b/include/sysemu/vhost-user-backend.h
> > @@ -0,0 +1,60 @@
> > +/*
> > + * QEMU vhost-user backend
> > + *
> > + * Copyright (C) 2018 Red Hat Inc
> > + *
> > + * Authors:
> > + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > + * See the COPYING file in the top-level directory.
> > + */
> > +#ifndef QEMU_VHOST_USER_BACKEND_H
> > +#define QEMU_VHOST_USER_BACKEND_H
> > +
> > +#include "qom/object.h"
> > +#include "exec/memory.h"
> > +#include "qemu/option.h"
> > +#include "qemu/bitmap.h"
> > +#include "hw/virtio/vhost.h"
> > +#include "hw/virtio/vhost-user.h"
> > +#include "chardev/char-fe.h"
> > +#include "io/channel.h"
> > +
> > +#define TYPE_VHOST_USER_BACKEND "vhost-user-backend"
> > +#define VHOST_USER_BACKEND(obj) \
> > +    OBJECT_CHECK(VhostUserBackend, (obj), TYPE_VHOST_USER_BACKEND)
> > +#define VHOST_USER_BACKEND_GET_CLASS(obj) \
> > +    OBJECT_GET_CLASS(VhostUserBackendClass, (obj), TYPE_VHOST_USER_BACKEND)
> > +#define VHOST_USER_BACKEND_CLASS(klass) \
> > +    OBJECT_CLASS_CHECK(VhostUserBackendClass, (klass), TYPE_VHOST_USER_BACKEND)
> > +
> > +typedef struct VhostUserBackend VhostUserBackend;
> > +typedef struct VhostUserBackendClass VhostUserBackendClass;
> > +
> > +struct VhostUserBackendClass {
> > +    ObjectClass parent_class;
> > +};
> > +
> > +struct VhostUserBackend {
> > +    /* private */
> > +    Object parent;
> > +
> > +    char *cmd;
> > +    char *chr_name;
> > +
> > +    CharBackend chr;
> > +    VhostUserState vhost_user;
> > +    struct vhost_dev dev;
> > +    QIOChannel *child;
> > +    VirtIODevice *vdev;
> > +    bool started;
> > +    bool completed;
> > +};
> > +
> > +int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> > +                                unsigned nvqs, Error **errp);
> > +void vhost_user_backend_start(VhostUserBackend *b);
> > +void vhost_user_backend_stop(VhostUserBackend *b);
> > +
> > +#endif
> > diff --git a/backends/vhost-user.c b/backends/vhost-user.c
> > new file mode 100644
> > index 0000000000..bf39c0751d
> > --- /dev/null
> > +++ b/backends/vhost-user.c
> > @@ -0,0 +1,244 @@
> > +/*
> > + * QEMU vhost-user backend
> > + *
> > + * Copyright (C) 2018 Red Hat Inc
> > + *
> > + * Authors:
> > + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > + * See the COPYING file in the top-level directory.
> > + */
> > +
> > +
> > +#include "qemu/osdep.h"
> > +#include "hw/qdev.h"
> > +#include "qapi/error.h"
> > +#include "qapi/qmp/qerror.h"
> > +#include "qemu/error-report.h"
> > +#include "qom/object_interfaces.h"
> > +#include "sysemu/vhost-user-backend.h"
> > +#include "sysemu/kvm.h"
> > +#include "io/channel-command.h"
> > +#include "hw/virtio/virtio-bus.h"
> > +
> > +static bool
> > +ioeventfd_enabled(void)
> > +{
> > +    return kvm_enabled() && kvm_eventfds_enabled();
> > +}
> > +
> > +int
> > +vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> > +                            unsigned nvqs, Error **errp)
> > +{
> > +    int ret;
> > +
> > +    assert(!b->vdev && vdev);
> > +
> > +    if (!ioeventfd_enabled()) {
> > +        error_setg(errp, "vhost initialization failed: requires kvm");
> > +        return -1;
> > +    }
> > +
> > +    if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
> > +        return -1;
> > +    }
> > +
> > +    b->vdev = vdev;
> > +    b->dev.nvqs = nvqs;
> > +    b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
> > +
> > +    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
> > +    if (ret < 0) {
> > +        error_setg_errno(errp, -ret, "vhost initialization failed");
> > +        return -1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +void
> > +vhost_user_backend_start(VhostUserBackend *b)
> > +{
> > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > +    int ret, i ;
> > +
> > +    if (b->started) {
> > +        return;
> > +    }
> > +
> > +    if (!k->set_guest_notifiers) {
> > +        error_report("binding does not support guest notifiers");
> > +        return;
> > +    }
> > +
> > +    ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
> > +    if (ret < 0) {
> > +        return;
> > +    }
> > +
> > +    ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
> > +    if (ret < 0) {
> > +        error_report("Error binding guest notifier");
> > +        goto err_host_notifiers;
> > +    }
> > +
> > +    b->dev.acked_features = b->vdev->guest_features;
> > +    ret = vhost_dev_start(&b->dev, b->vdev);
> > +    if (ret < 0) {
> > +        error_report("Error start vhost dev");
> > +        goto err_guest_notifiers;
> > +    }
> > +
> > +    /* guest_notifier_mask/pending not used yet, so just unmask
> > +     * everything here.  virtio-pci will do the right thing by
> > +     * enabling/disabling irqfd.
> > +     */
> > +    for (i = 0; i < b->dev.nvqs; i++) {
> > +        vhost_virtqueue_mask(&b->dev, b->vdev,
> > +                             b->dev.vq_index + i, false);
> > +    }
> > +
> > +    b->started = true;
> > +    return;
> > +
> > +err_guest_notifiers:
> > +    k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
> > +err_host_notifiers:
> > +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> > +}
> > +
> > +void
> > +vhost_user_backend_stop(VhostUserBackend *b)
> > +{
> > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > +    int ret = 0;
> > +
> > +    if (!b->started) {
> > +        return;
> > +    }
> > +
> > +    vhost_dev_stop(&b->dev, b->vdev);
> > +
> > +    if (k->set_guest_notifiers) {
> > +        ret = k->set_guest_notifiers(qbus->parent,
> > +                                     b->dev.nvqs, false);
> > +        if (ret < 0) {
> > +            error_report("vhost guest notifier cleanup failed: %d", ret);
> > +        }
> > +    }
> > +    assert(ret >= 0);
> > +
> > +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> > +    b->started = false;
> > +}
> > +
> > +static void
> > +vhost_user_backend_complete(UserCreatable *uc, Error **errp)
> > +{
> > +    VhostUserBackend *b = VHOST_USER_BACKEND(uc);
> > +    Chardev *chr;
> > +
> > +    if (!b->chr_name) {
> > +        error_setg(errp, "You must specificy 'chardev'.");
> > +        return;
> > +    }
> > +
> > +    chr = qemu_chr_find(b->chr_name);
> > +    if (chr == NULL) {
> > +        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> > +                  "Chardev '%s' not found", b->chr_name);
> > +        return;
> > +    }
> > +
> > +    if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
> > +        return;
> > +    }
> > +
> > +    b->completed = true;
> > +    /* could vhost_dev_init() happen here, so early vhost-user message
> > +     * can be exchanged */
> > +}
> > +
> > +static void set_chardev(Object *obj, const char *value, Error **errp)
> > +{
> > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > +
> > +    if (b->completed) {
> > +        error_setg(errp, QERR_PERMISSION_DENIED);
> > +    } else {
> > +        g_free(b->chr_name);
> > +        b->chr_name = g_strdup(value);
> > +    }
> > +}
> > +
> > +static char *get_chardev(Object *obj, Error **errp)
> > +{
> > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > +    Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
> > +
> > +    if (chr && chr->label) {
> > +        return g_strdup(chr->label);
> > +    }
> > +
> > +    return NULL;
> > +}
> > +
> > +static void vhost_user_backend_init(Object *obj)
> > +{
> > +    object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
> > +}
> > +
> > +static void vhost_user_backend_finalize(Object *obj)
> > +{
> > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > +
> > +    g_free(b->dev.vqs);
> > +    g_free(b->chr_name);
> > +
> > +    vhost_user_cleanup(&b->vhost_user);
> > +    qemu_chr_fe_deinit(&b->chr, true);
> > +
> > +    if (b->child) {
> > +        object_unref(OBJECT(b->child));
> > +    }
> > +}
> > +
> > +static bool
> > +vhost_user_backend_can_be_deleted(UserCreatable *uc)
> > +{
> > +    return true;
> > +}
> > +
> > +static void
> > +vhost_user_backend_class_init(ObjectClass *oc, void *data)
> > +{
> > +    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
> > +
> > +    ucc->complete = vhost_user_backend_complete;
> > +    ucc->can_be_deleted = vhost_user_backend_can_be_deleted;
> > +}
> > +
> > +static const TypeInfo vhost_user_backend_info = {
> > +    .name = TYPE_VHOST_USER_BACKEND,
> > +    .parent = TYPE_OBJECT,
> > +    .instance_size = sizeof(VhostUserBackend),
> > +    .instance_init = vhost_user_backend_init,
> > +    .instance_finalize = vhost_user_backend_finalize,
> > +    .class_size = sizeof(VhostUserBackendClass),
> > +    .class_init = vhost_user_backend_class_init,
> > +    .interfaces = (InterfaceInfo[]) {
> > +        { TYPE_USER_CREATABLE },
> > +        { }
> > +    }
> > +};
> > +
> > +static void register_types(void)
> > +{
> > +    type_register_static(&vhost_user_backend_info);
> > +}
> > +
> > +type_init(register_types);
> > diff --git a/vl.c b/vl.c
> > index 9e4dba7f92..43012ee6a3 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -2784,7 +2784,8 @@ static bool object_create_initial(const char *type, QemuOpts *opts)
> >      }
> >
> >  #if defined(CONFIG_VHOST_USER) && defined(CONFIG_LINUX)
> > -    if (g_str_equal(type, "cryptodev-vhost-user")) {
> > +    if (g_str_equal(type, "cryptodev-vhost-user") ||
> > +        g_str_equal(type, "vhost-user-backend")) {
> >          return false;
> >      }
> >  #endif
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 16b6264412..e077fe788d 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -1424,6 +1424,8 @@ F: hw/*/*vhost*
> >  F: docs/interop/vhost-user.json
> >  F: docs/interop/vhost-user.txt
> >  F: contrib/vhost-user-*/
> > +F: backends/vhost-user.c
> > +F: include/sysemu/vhost-user-backend.h
> >
> >  virtio
> >  M: Michael S. Tsirkin <mst@redhat.com>
> > diff --git a/backends/Makefile.objs b/backends/Makefile.objs
> > index 717fcbdae4..a5ec0bf907 100644
> > --- a/backends/Makefile.objs
> > +++ b/backends/Makefile.objs
> > @@ -12,7 +12,8 @@ common-obj-y += cryptodev-builtin.o
> >  ifeq ($(CONFIG_VIRTIO),y)
> >  common-obj-y += cryptodev-vhost.o
> >  common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += \
> > -    cryptodev-vhost-user.o
> > +    cryptodev-vhost-user.o \
> > +    vhost-user.o
> >  endif
> >
> >  common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 06ef1a7c5c..24315a4cda 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -4203,6 +4203,26 @@ secondary:
> >  If you want to know the detail of above command line, you can read
> >  the colo-compare git log.
> >
> > +@item -object vhost-user-backend,id=id=@var{id},chardev=@var{chardevid}
> > +
> > +Create a vhost-user-backend object that holds a connection to a
> > +vhost-user backend and can be referenced from virtio/vhost-user
> > +devices that support it.
> > +
> > +The @var{id} parameter is a unique ID that will be used to reference
> > +this vhost-user backend from the @option{vhost-user} device. The
> > +@var{chardev} parameter is the unique ID of a character device backend
> > +that provides the connection to the vhost-user slave process. (Since 3.2)
> > +
> > +@example
> > +
> > + # qemu-system-x86_64 \
> > +   [...] \
> > +   -object vhost-user-backend,id=vuid,chardev=char0 \
> > +   -device vhost-user-input-pci,vhost-user=vuid
> > +   [...]
> > +@end example
> > +
> >  @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
> >
> >  Creates a cryptodev backend which executes crypto opreation from
> > --
> > 2.20.1.519.g8feddda32c

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends
  2019-02-07 17:42   ` Eric Blake
@ 2019-02-07 18:45     ` Marc-André Lureau
  0 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-07 18:45 UTC (permalink / raw)
  To: Eric Blake; +Cc: qemu-devel, Gerd Hoffmann, Michael S. Tsirkin

Hi

On Thu, Feb 7, 2019 at 6:42 PM Eric Blake <eblake@redhat.com> wrote:
>
> On 2/7/19 10:54 AM, Marc-André Lureau wrote:
> > As discussed during "[PATCH v4 00/29] vhost-user for input & GPU"
> > review, let's define a common set of backend conventions to help with
> > management layer implementation, and interoperability.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >  MAINTAINERS                  |   1 +
> >  docs/interop/vhost-user.json | 219 +++++++++++++++++++++++++++++++++++
> >  docs/interop/vhost-user.txt  | 101 +++++++++++++++-
> >  3 files changed, 319 insertions(+), 2 deletions(-)
> >  create mode 100644 docs/interop/vhost-user.json
>
> > +##
> > +# @VHostUserBackendType:
> > +#
> > +# List the various vhost user backend types.
> > +#
> > +# @net: virtio net
> > +# @block: virtio block
> > +# @console: virtio console
> > +# @rng: virtio rng
> > +# @balloon: virtio balloon
> > +# @rpmsg: virtio remote processor messaging
> > +# @scsi: virtio scsi
> > +# @9p: 9p virtio console
> > +# @rproc-serial: virtio remoteproc serial link
> > +# @caif: virtio caif
> > +# @gpu: virtio gpu
> > +# @input: virtio input
> > +# @vsock: virtio vsock transport
> > +# @crypto: virtio crypto
> > +#
> > +# Since: 3.2
>
> s/3.2/4.0/g in your patch series

done

>
> > +##
> > +{
> > +  'enum': 'VHostUserBackendType',
> > +  'data': [ 'net', 'block', 'console', 'rng', 'balloon', 'rpmsg',
> > +            'scsi', '9p', 'rproc-serial', 'caif', 'gpu', 'input', 'vsock',
> > +            'crypto' ]
> > +}
>
> Worth alphabetizing? Not a strong requirement, though, if this order
> makes more sense.

It's in the VIRTIO_ID* order. But there is no reason to keep it that
way. Well, if we keep it alphabetically sorted, we should put one on
each line, to avoid churn..

>
>
> > +#
> > +# Top-down, the list of directories goes from general to specific.
> > +#
> > +# Management software should build a list of files from all three
> > +# locations, then sort the list by filename (i.e., last pathname
>
> perhaps s/filename/basename/

ok

> > +# component). Management software should choose the first JSON file on
> > +# the sorted list that matches the search criteria. If a more specific
> > +# directory has a file with same name as a less specific directory, then
> > +# the file in the more specific directory takes effect. If the more
> > +# specific file is zero length, it hides the less specific one.
> > +#
>
> > +++ b/docs/interop/vhost-user.txt
> > @@ -17,8 +17,13 @@ The protocol defines 2 sides of the communication, master and slave. Master is
> >  the application that shares its virtqueues, in our case QEMU. Slave is the
> >  consumer of the virtqueues.
> >
> > -In the current implementation QEMU is the Master, and the Slave is intended to
> > -be a software Ethernet switch running in user space, such as Snabbswitch.
> > +In the current implementation QEMU is the Master, and the Slave is the
> > +external process consuming the virtio queues, for example a software
> > +Ethernet switch running in user space, such as Snabbswitch, or a block
>
> Is 'slirp' any better than 'Snabbswitch' as a demonstration of
> user-space networking?

pre-existing, skip

>
> > +device backend processing read & write to a virtual disk. In order to
> > +facilitate interoperability between various backend implementations,
> > +it is recommended to follow the "Backend program conventions"
> > +described in this document.
> >
>
> > +
> > +The backend program must end (as quickly and cleanly as possible) when
> > +the SIGTERM signal is received. Eventually, it may be SIGKILL by the
>
> s/be/receive/

ok

>
> > +management layer after a few seconds.
> > +
> > +The following command line options have an expected behaviour. They
> > +are mandatory, unless explicitly said differently:
> > +
> > +* --socket-path=PATH
> > +
> > +This option specify the location of the vhost-user Unix domain socket.
> > +It is incompatible with --fd.
> > +
> > +* --fd=FDNUM
> > +
> > +When this argument is given, the backend program is started with the
> > +vhost-user socket as file descriptor FDNUM. It is incompatible with
> > +--socket-path.
>
> Do we also want to require support for systemd-style
> LISTEN_PID/LISTEN_FDS socket activation?

what is the difference with --fd= here? This would allow all
vhost-user-backend to be started on demand by systemd I suppose, but
do we need it? Could it be added later?

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend
  2019-02-07 18:29     ` Marc-André Lureau
@ 2019-02-07 19:18       ` Michael S. Tsirkin
  2019-02-08 11:15         ` Marc-André Lureau
  0 siblings, 1 reply; 19+ messages in thread
From: Michael S. Tsirkin @ 2019-02-07 19:18 UTC (permalink / raw)
  To: Marc-André Lureau; +Cc: qemu-devel, Gerd Hoffmann, Paolo Bonzini

On Thu, Feb 07, 2019 at 07:29:20PM +0100, Marc-André Lureau wrote:
> Hi
> 
> On Thu, Feb 7, 2019 at 6:36 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Thu, Feb 07, 2019 at 05:54:42PM +0100, Marc-André Lureau wrote:
> > > Create a vhost-user-backend object that holds a connection to a
> > > vhost-user backend and can be referenced from virtio devices that
> > > support it. See later patches for input & gpu usage.
> > >
> > > A chardev must be specified to communicate with the vhost-user
> > > backend, ex: -chardev socket,id=char0,path=/tmp/foo.sock -object
> > > vhost-user-backend,id=vuid,chardev=char0.
> > >
> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > So having an internal object that can maintain runtime state
> > might be a good idea. However I don't yet really see
> > what kind of property could such an object have that
> > the char device couldn't.>
> > I could see value if user did not have to specify
> > a completely separate device.
> >
> > Consider:
> >
> > -chardev socket,id=char0,path=/tmp/foo.sock
> > -object vhost-user-backend,id=vuid,chardev=char0
> > -device vhost-user-input-pci,vhost-user=vuid
> >
> >
> > There's 3 times vhost-user here, and nothing actually says it's
> > virtio-input, that is implicit :(
> >
> > So I feel CLI needs to change.  But I do think the idea of
> > an object in between does have some potential.
> 
> Ok, I dropped the -object from CLI. It can be added later if needed.
> 
> It makes some sense imho to wrap all the configuration/documentation
> in a backend object. But since we have only chardev= now (cmd= is
> being postponed), and I can only speculate on what could come next,
> let's just have it as internal helper for now.
> 
> I'll adjust/resend this series, this will also impact the -gpu and
> libvirt series.

But, can we make it so that these devices are created using
-device virtio-gpu-pci etc?
This is not a vhost user device, vhost user is the backend.


> >
> > Consider virtio net which now has modern, legacy and transitional
> > variants. How is vhost-user-X type going to scale there?
> > That's a problem worth solving IMHO.
> >
> > Also, there's a problem right now in that if backend
> > connects before device is available (e.g. because we
> > want to hotplug the device later) then we can not
> > validate the backend. So it will fail way later.
> > I am not sure how much do we want to validate,
> > but if e.g. it's a different device type completely,
> > that seems like a reasonable thing to validate.
> >
> > So I do see potential in a vhost user backend object
> > but then it has to encapsulate all vhost user things,
> > such that you can connect a virtio device to a
> > vhost user object.
> >
> >
> >
> >
> >
> > > ---
> > >  include/sysemu/vhost-user-backend.h |  60 +++++++
> > >  backends/vhost-user.c               | 244 ++++++++++++++++++++++++++++
> > >  vl.c                                |   3 +-
> > >  MAINTAINERS                         |   2 +
> > >  backends/Makefile.objs              |   3 +-
> > >  qemu-options.hx                     |  20 +++
> > >  6 files changed, 330 insertions(+), 2 deletions(-)
> > >  create mode 100644 include/sysemu/vhost-user-backend.h
> > >  create mode 100644 backends/vhost-user.c
> > >
> > > diff --git a/include/sysemu/vhost-user-backend.h b/include/sysemu/vhost-user-backend.h
> > > new file mode 100644
> > > index 0000000000..60f811cae7
> > > --- /dev/null
> > > +++ b/include/sysemu/vhost-user-backend.h
> > > @@ -0,0 +1,60 @@
> > > +/*
> > > + * QEMU vhost-user backend
> > > + *
> > > + * Copyright (C) 2018 Red Hat Inc
> > > + *
> > > + * Authors:
> > > + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> > > + *
> > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > + * See the COPYING file in the top-level directory.
> > > + */
> > > +#ifndef QEMU_VHOST_USER_BACKEND_H
> > > +#define QEMU_VHOST_USER_BACKEND_H
> > > +
> > > +#include "qom/object.h"
> > > +#include "exec/memory.h"
> > > +#include "qemu/option.h"
> > > +#include "qemu/bitmap.h"
> > > +#include "hw/virtio/vhost.h"
> > > +#include "hw/virtio/vhost-user.h"
> > > +#include "chardev/char-fe.h"
> > > +#include "io/channel.h"
> > > +
> > > +#define TYPE_VHOST_USER_BACKEND "vhost-user-backend"
> > > +#define VHOST_USER_BACKEND(obj) \
> > > +    OBJECT_CHECK(VhostUserBackend, (obj), TYPE_VHOST_USER_BACKEND)
> > > +#define VHOST_USER_BACKEND_GET_CLASS(obj) \
> > > +    OBJECT_GET_CLASS(VhostUserBackendClass, (obj), TYPE_VHOST_USER_BACKEND)
> > > +#define VHOST_USER_BACKEND_CLASS(klass) \
> > > +    OBJECT_CLASS_CHECK(VhostUserBackendClass, (klass), TYPE_VHOST_USER_BACKEND)
> > > +
> > > +typedef struct VhostUserBackend VhostUserBackend;
> > > +typedef struct VhostUserBackendClass VhostUserBackendClass;
> > > +
> > > +struct VhostUserBackendClass {
> > > +    ObjectClass parent_class;
> > > +};
> > > +
> > > +struct VhostUserBackend {
> > > +    /* private */
> > > +    Object parent;
> > > +
> > > +    char *cmd;
> > > +    char *chr_name;
> > > +
> > > +    CharBackend chr;
> > > +    VhostUserState vhost_user;
> > > +    struct vhost_dev dev;
> > > +    QIOChannel *child;
> > > +    VirtIODevice *vdev;
> > > +    bool started;
> > > +    bool completed;
> > > +};
> > > +
> > > +int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> > > +                                unsigned nvqs, Error **errp);
> > > +void vhost_user_backend_start(VhostUserBackend *b);
> > > +void vhost_user_backend_stop(VhostUserBackend *b);
> > > +
> > > +#endif
> > > diff --git a/backends/vhost-user.c b/backends/vhost-user.c
> > > new file mode 100644
> > > index 0000000000..bf39c0751d
> > > --- /dev/null
> > > +++ b/backends/vhost-user.c
> > > @@ -0,0 +1,244 @@
> > > +/*
> > > + * QEMU vhost-user backend
> > > + *
> > > + * Copyright (C) 2018 Red Hat Inc
> > > + *
> > > + * Authors:
> > > + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> > > + *
> > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > + * See the COPYING file in the top-level directory.
> > > + */
> > > +
> > > +
> > > +#include "qemu/osdep.h"
> > > +#include "hw/qdev.h"
> > > +#include "qapi/error.h"
> > > +#include "qapi/qmp/qerror.h"
> > > +#include "qemu/error-report.h"
> > > +#include "qom/object_interfaces.h"
> > > +#include "sysemu/vhost-user-backend.h"
> > > +#include "sysemu/kvm.h"
> > > +#include "io/channel-command.h"
> > > +#include "hw/virtio/virtio-bus.h"
> > > +
> > > +static bool
> > > +ioeventfd_enabled(void)
> > > +{
> > > +    return kvm_enabled() && kvm_eventfds_enabled();
> > > +}
> > > +
> > > +int
> > > +vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> > > +                            unsigned nvqs, Error **errp)
> > > +{
> > > +    int ret;
> > > +
> > > +    assert(!b->vdev && vdev);
> > > +
> > > +    if (!ioeventfd_enabled()) {
> > > +        error_setg(errp, "vhost initialization failed: requires kvm");
> > > +        return -1;
> > > +    }
> > > +
> > > +    if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
> > > +        return -1;
> > > +    }
> > > +
> > > +    b->vdev = vdev;
> > > +    b->dev.nvqs = nvqs;
> > > +    b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
> > > +
> > > +    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
> > > +    if (ret < 0) {
> > > +        error_setg_errno(errp, -ret, "vhost initialization failed");
> > > +        return -1;
> > > +    }
> > > +
> > > +    return 0;
> > > +}
> > > +
> > > +void
> > > +vhost_user_backend_start(VhostUserBackend *b)
> > > +{
> > > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> > > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > > +    int ret, i ;
> > > +
> > > +    if (b->started) {
> > > +        return;
> > > +    }
> > > +
> > > +    if (!k->set_guest_notifiers) {
> > > +        error_report("binding does not support guest notifiers");
> > > +        return;
> > > +    }
> > > +
> > > +    ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
> > > +    if (ret < 0) {
> > > +        return;
> > > +    }
> > > +
> > > +    ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
> > > +    if (ret < 0) {
> > > +        error_report("Error binding guest notifier");
> > > +        goto err_host_notifiers;
> > > +    }
> > > +
> > > +    b->dev.acked_features = b->vdev->guest_features;
> > > +    ret = vhost_dev_start(&b->dev, b->vdev);
> > > +    if (ret < 0) {
> > > +        error_report("Error start vhost dev");
> > > +        goto err_guest_notifiers;
> > > +    }
> > > +
> > > +    /* guest_notifier_mask/pending not used yet, so just unmask
> > > +     * everything here.  virtio-pci will do the right thing by
> > > +     * enabling/disabling irqfd.
> > > +     */
> > > +    for (i = 0; i < b->dev.nvqs; i++) {
> > > +        vhost_virtqueue_mask(&b->dev, b->vdev,
> > > +                             b->dev.vq_index + i, false);
> > > +    }
> > > +
> > > +    b->started = true;
> > > +    return;
> > > +
> > > +err_guest_notifiers:
> > > +    k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
> > > +err_host_notifiers:
> > > +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> > > +}
> > > +
> > > +void
> > > +vhost_user_backend_stop(VhostUserBackend *b)
> > > +{
> > > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> > > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > > +    int ret = 0;
> > > +
> > > +    if (!b->started) {
> > > +        return;
> > > +    }
> > > +
> > > +    vhost_dev_stop(&b->dev, b->vdev);
> > > +
> > > +    if (k->set_guest_notifiers) {
> > > +        ret = k->set_guest_notifiers(qbus->parent,
> > > +                                     b->dev.nvqs, false);
> > > +        if (ret < 0) {
> > > +            error_report("vhost guest notifier cleanup failed: %d", ret);
> > > +        }
> > > +    }
> > > +    assert(ret >= 0);
> > > +
> > > +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> > > +    b->started = false;
> > > +}
> > > +
> > > +static void
> > > +vhost_user_backend_complete(UserCreatable *uc, Error **errp)
> > > +{
> > > +    VhostUserBackend *b = VHOST_USER_BACKEND(uc);
> > > +    Chardev *chr;
> > > +
> > > +    if (!b->chr_name) {
> > > +        error_setg(errp, "You must specificy 'chardev'.");
> > > +        return;
> > > +    }
> > > +
> > > +    chr = qemu_chr_find(b->chr_name);
> > > +    if (chr == NULL) {
> > > +        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> > > +                  "Chardev '%s' not found", b->chr_name);
> > > +        return;
> > > +    }
> > > +
> > > +    if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
> > > +        return;
> > > +    }
> > > +
> > > +    b->completed = true;
> > > +    /* could vhost_dev_init() happen here, so early vhost-user message
> > > +     * can be exchanged */
> > > +}
> > > +
> > > +static void set_chardev(Object *obj, const char *value, Error **errp)
> > > +{
> > > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > > +
> > > +    if (b->completed) {
> > > +        error_setg(errp, QERR_PERMISSION_DENIED);
> > > +    } else {
> > > +        g_free(b->chr_name);
> > > +        b->chr_name = g_strdup(value);
> > > +    }
> > > +}
> > > +
> > > +static char *get_chardev(Object *obj, Error **errp)
> > > +{
> > > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > > +    Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
> > > +
> > > +    if (chr && chr->label) {
> > > +        return g_strdup(chr->label);
> > > +    }
> > > +
> > > +    return NULL;
> > > +}
> > > +
> > > +static void vhost_user_backend_init(Object *obj)
> > > +{
> > > +    object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
> > > +}
> > > +
> > > +static void vhost_user_backend_finalize(Object *obj)
> > > +{
> > > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > > +
> > > +    g_free(b->dev.vqs);
> > > +    g_free(b->chr_name);
> > > +
> > > +    vhost_user_cleanup(&b->vhost_user);
> > > +    qemu_chr_fe_deinit(&b->chr, true);
> > > +
> > > +    if (b->child) {
> > > +        object_unref(OBJECT(b->child));
> > > +    }
> > > +}
> > > +
> > > +static bool
> > > +vhost_user_backend_can_be_deleted(UserCreatable *uc)
> > > +{
> > > +    return true;
> > > +}
> > > +
> > > +static void
> > > +vhost_user_backend_class_init(ObjectClass *oc, void *data)
> > > +{
> > > +    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
> > > +
> > > +    ucc->complete = vhost_user_backend_complete;
> > > +    ucc->can_be_deleted = vhost_user_backend_can_be_deleted;
> > > +}
> > > +
> > > +static const TypeInfo vhost_user_backend_info = {
> > > +    .name = TYPE_VHOST_USER_BACKEND,
> > > +    .parent = TYPE_OBJECT,
> > > +    .instance_size = sizeof(VhostUserBackend),
> > > +    .instance_init = vhost_user_backend_init,
> > > +    .instance_finalize = vhost_user_backend_finalize,
> > > +    .class_size = sizeof(VhostUserBackendClass),
> > > +    .class_init = vhost_user_backend_class_init,
> > > +    .interfaces = (InterfaceInfo[]) {
> > > +        { TYPE_USER_CREATABLE },
> > > +        { }
> > > +    }
> > > +};
> > > +
> > > +static void register_types(void)
> > > +{
> > > +    type_register_static(&vhost_user_backend_info);
> > > +}
> > > +
> > > +type_init(register_types);
> > > diff --git a/vl.c b/vl.c
> > > index 9e4dba7f92..43012ee6a3 100644
> > > --- a/vl.c
> > > +++ b/vl.c
> > > @@ -2784,7 +2784,8 @@ static bool object_create_initial(const char *type, QemuOpts *opts)
> > >      }
> > >
> > >  #if defined(CONFIG_VHOST_USER) && defined(CONFIG_LINUX)
> > > -    if (g_str_equal(type, "cryptodev-vhost-user")) {
> > > +    if (g_str_equal(type, "cryptodev-vhost-user") ||
> > > +        g_str_equal(type, "vhost-user-backend")) {
> > >          return false;
> > >      }
> > >  #endif
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 16b6264412..e077fe788d 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -1424,6 +1424,8 @@ F: hw/*/*vhost*
> > >  F: docs/interop/vhost-user.json
> > >  F: docs/interop/vhost-user.txt
> > >  F: contrib/vhost-user-*/
> > > +F: backends/vhost-user.c
> > > +F: include/sysemu/vhost-user-backend.h
> > >
> > >  virtio
> > >  M: Michael S. Tsirkin <mst@redhat.com>
> > > diff --git a/backends/Makefile.objs b/backends/Makefile.objs
> > > index 717fcbdae4..a5ec0bf907 100644
> > > --- a/backends/Makefile.objs
> > > +++ b/backends/Makefile.objs
> > > @@ -12,7 +12,8 @@ common-obj-y += cryptodev-builtin.o
> > >  ifeq ($(CONFIG_VIRTIO),y)
> > >  common-obj-y += cryptodev-vhost.o
> > >  common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += \
> > > -    cryptodev-vhost-user.o
> > > +    cryptodev-vhost-user.o \
> > > +    vhost-user.o
> > >  endif
> > >
> > >  common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
> > > diff --git a/qemu-options.hx b/qemu-options.hx
> > > index 06ef1a7c5c..24315a4cda 100644
> > > --- a/qemu-options.hx
> > > +++ b/qemu-options.hx
> > > @@ -4203,6 +4203,26 @@ secondary:
> > >  If you want to know the detail of above command line, you can read
> > >  the colo-compare git log.
> > >
> > > +@item -object vhost-user-backend,id=id=@var{id},chardev=@var{chardevid}
> > > +
> > > +Create a vhost-user-backend object that holds a connection to a
> > > +vhost-user backend and can be referenced from virtio/vhost-user
> > > +devices that support it.
> > > +
> > > +The @var{id} parameter is a unique ID that will be used to reference
> > > +this vhost-user backend from the @option{vhost-user} device. The
> > > +@var{chardev} parameter is the unique ID of a character device backend
> > > +that provides the connection to the vhost-user slave process. (Since 3.2)
> > > +
> > > +@example
> > > +
> > > + # qemu-system-x86_64 \
> > > +   [...] \
> > > +   -object vhost-user-backend,id=vuid,chardev=char0 \
> > > +   -device vhost-user-input-pci,vhost-user=vuid
> > > +   [...]
> > > +@end example
> > > +
> > >  @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
> > >
> > >  Creates a cryptodev backend which executes crypto opreation from
> > > --
> > > 2.20.1.519.g8feddda32c

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend
  2019-02-07 19:18       ` Michael S. Tsirkin
@ 2019-02-08 11:15         ` Marc-André Lureau
  0 siblings, 0 replies; 19+ messages in thread
From: Marc-André Lureau @ 2019-02-08 11:15 UTC (permalink / raw)
  To: Michael S. Tsirkin; +Cc: Paolo Bonzini, qemu-devel, Gerd Hoffmann

Hi

On Thu, Feb 7, 2019 at 8:27 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Feb 07, 2019 at 07:29:20PM +0100, Marc-André Lureau wrote:
> > Hi
> >
> > On Thu, Feb 7, 2019 at 6:36 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > On Thu, Feb 07, 2019 at 05:54:42PM +0100, Marc-André Lureau wrote:
> > > > Create a vhost-user-backend object that holds a connection to a
> > > > vhost-user backend and can be referenced from virtio devices that
> > > > support it. See later patches for input & gpu usage.
> > > >
> > > > A chardev must be specified to communicate with the vhost-user
> > > > backend, ex: -chardev socket,id=char0,path=/tmp/foo.sock -object
> > > > vhost-user-backend,id=vuid,chardev=char0.
> > > >
> > > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > >
> > > So having an internal object that can maintain runtime state
> > > might be a good idea. However I don't yet really see
> > > what kind of property could such an object have that
> > > the char device couldn't.>
> > > I could see value if user did not have to specify
> > > a completely separate device.
> > >
> > > Consider:
> > >
> > > -chardev socket,id=char0,path=/tmp/foo.sock
> > > -object vhost-user-backend,id=vuid,chardev=char0
> > > -device vhost-user-input-pci,vhost-user=vuid
> > >
> > >
> > > There's 3 times vhost-user here, and nothing actually says it's
> > > virtio-input, that is implicit :(
> > >
> > > So I feel CLI needs to change.  But I do think the idea of
> > > an object in between does have some potential.
> >
> > Ok, I dropped the -object from CLI. It can be added later if needed.
> >
> > It makes some sense imho to wrap all the configuration/documentation
> > in a backend object. But since we have only chardev= now (cmd= is
> > being postponed), and I can only speculate on what could come next,
> > let's just have it as internal helper for now.
> >
> > I'll adjust/resend this series, this will also impact the -gpu and
> > libvirt series.
>
> But, can we make it so that these devices are created using
> -device virtio-gpu-pci etc?
> This is not a vhost user device, vhost user is the backend.

I am not sure I understand your question. I updated the series so that
vhost-user-backend is an internal helper object (created by
vhost-user-{input,gpu}-pci devices, not exposed to the CLI).

>
>
> > >
> > > Consider virtio net which now has modern, legacy and transitional
> > > variants. How is vhost-user-X type going to scale there?
> > > That's a problem worth solving IMHO.
> > >
> > > Also, there's a problem right now in that if backend
> > > connects before device is available (e.g. because we
> > > want to hotplug the device later) then we can not
> > > validate the backend. So it will fail way later.
> > > I am not sure how much do we want to validate,
> > > but if e.g. it's a different device type completely,
> > > that seems like a reasonable thing to validate.
> > >
> > > So I do see potential in a vhost user backend object
> > > but then it has to encapsulate all vhost user things,
> > > such that you can connect a virtio device to a
> > > vhost user object.
> > >
> > >
> > >
> > >
> > >
> > > > ---
> > > >  include/sysemu/vhost-user-backend.h |  60 +++++++
> > > >  backends/vhost-user.c               | 244 ++++++++++++++++++++++++++++
> > > >  vl.c                                |   3 +-
> > > >  MAINTAINERS                         |   2 +
> > > >  backends/Makefile.objs              |   3 +-
> > > >  qemu-options.hx                     |  20 +++
> > > >  6 files changed, 330 insertions(+), 2 deletions(-)
> > > >  create mode 100644 include/sysemu/vhost-user-backend.h
> > > >  create mode 100644 backends/vhost-user.c
> > > >
> > > > diff --git a/include/sysemu/vhost-user-backend.h b/include/sysemu/vhost-user-backend.h
> > > > new file mode 100644
> > > > index 0000000000..60f811cae7
> > > > --- /dev/null
> > > > +++ b/include/sysemu/vhost-user-backend.h
> > > > @@ -0,0 +1,60 @@
> > > > +/*
> > > > + * QEMU vhost-user backend
> > > > + *
> > > > + * Copyright (C) 2018 Red Hat Inc
> > > > + *
> > > > + * Authors:
> > > > + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> > > > + *
> > > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > > + * See the COPYING file in the top-level directory.
> > > > + */
> > > > +#ifndef QEMU_VHOST_USER_BACKEND_H
> > > > +#define QEMU_VHOST_USER_BACKEND_H
> > > > +
> > > > +#include "qom/object.h"
> > > > +#include "exec/memory.h"
> > > > +#include "qemu/option.h"
> > > > +#include "qemu/bitmap.h"
> > > > +#include "hw/virtio/vhost.h"
> > > > +#include "hw/virtio/vhost-user.h"
> > > > +#include "chardev/char-fe.h"
> > > > +#include "io/channel.h"
> > > > +
> > > > +#define TYPE_VHOST_USER_BACKEND "vhost-user-backend"
> > > > +#define VHOST_USER_BACKEND(obj) \
> > > > +    OBJECT_CHECK(VhostUserBackend, (obj), TYPE_VHOST_USER_BACKEND)
> > > > +#define VHOST_USER_BACKEND_GET_CLASS(obj) \
> > > > +    OBJECT_GET_CLASS(VhostUserBackendClass, (obj), TYPE_VHOST_USER_BACKEND)
> > > > +#define VHOST_USER_BACKEND_CLASS(klass) \
> > > > +    OBJECT_CLASS_CHECK(VhostUserBackendClass, (klass), TYPE_VHOST_USER_BACKEND)
> > > > +
> > > > +typedef struct VhostUserBackend VhostUserBackend;
> > > > +typedef struct VhostUserBackendClass VhostUserBackendClass;
> > > > +
> > > > +struct VhostUserBackendClass {
> > > > +    ObjectClass parent_class;
> > > > +};
> > > > +
> > > > +struct VhostUserBackend {
> > > > +    /* private */
> > > > +    Object parent;
> > > > +
> > > > +    char *cmd;
> > > > +    char *chr_name;
> > > > +
> > > > +    CharBackend chr;
> > > > +    VhostUserState vhost_user;
> > > > +    struct vhost_dev dev;
> > > > +    QIOChannel *child;
> > > > +    VirtIODevice *vdev;
> > > > +    bool started;
> > > > +    bool completed;
> > > > +};
> > > > +
> > > > +int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> > > > +                                unsigned nvqs, Error **errp);
> > > > +void vhost_user_backend_start(VhostUserBackend *b);
> > > > +void vhost_user_backend_stop(VhostUserBackend *b);
> > > > +
> > > > +#endif
> > > > diff --git a/backends/vhost-user.c b/backends/vhost-user.c
> > > > new file mode 100644
> > > > index 0000000000..bf39c0751d
> > > > --- /dev/null
> > > > +++ b/backends/vhost-user.c
> > > > @@ -0,0 +1,244 @@
> > > > +/*
> > > > + * QEMU vhost-user backend
> > > > + *
> > > > + * Copyright (C) 2018 Red Hat Inc
> > > > + *
> > > > + * Authors:
> > > > + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> > > > + *
> > > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > > + * See the COPYING file in the top-level directory.
> > > > + */
> > > > +
> > > > +
> > > > +#include "qemu/osdep.h"
> > > > +#include "hw/qdev.h"
> > > > +#include "qapi/error.h"
> > > > +#include "qapi/qmp/qerror.h"
> > > > +#include "qemu/error-report.h"
> > > > +#include "qom/object_interfaces.h"
> > > > +#include "sysemu/vhost-user-backend.h"
> > > > +#include "sysemu/kvm.h"
> > > > +#include "io/channel-command.h"
> > > > +#include "hw/virtio/virtio-bus.h"
> > > > +
> > > > +static bool
> > > > +ioeventfd_enabled(void)
> > > > +{
> > > > +    return kvm_enabled() && kvm_eventfds_enabled();
> > > > +}
> > > > +
> > > > +int
> > > > +vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> > > > +                            unsigned nvqs, Error **errp)
> > > > +{
> > > > +    int ret;
> > > > +
> > > > +    assert(!b->vdev && vdev);
> > > > +
> > > > +    if (!ioeventfd_enabled()) {
> > > > +        error_setg(errp, "vhost initialization failed: requires kvm");
> > > > +        return -1;
> > > > +    }
> > > > +
> > > > +    if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
> > > > +        return -1;
> > > > +    }
> > > > +
> > > > +    b->vdev = vdev;
> > > > +    b->dev.nvqs = nvqs;
> > > > +    b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
> > > > +
> > > > +    ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
> > > > +    if (ret < 0) {
> > > > +        error_setg_errno(errp, -ret, "vhost initialization failed");
> > > > +        return -1;
> > > > +    }
> > > > +
> > > > +    return 0;
> > > > +}
> > > > +
> > > > +void
> > > > +vhost_user_backend_start(VhostUserBackend *b)
> > > > +{
> > > > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> > > > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > > > +    int ret, i ;
> > > > +
> > > > +    if (b->started) {
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    if (!k->set_guest_notifiers) {
> > > > +        error_report("binding does not support guest notifiers");
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
> > > > +    if (ret < 0) {
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
> > > > +    if (ret < 0) {
> > > > +        error_report("Error binding guest notifier");
> > > > +        goto err_host_notifiers;
> > > > +    }
> > > > +
> > > > +    b->dev.acked_features = b->vdev->guest_features;
> > > > +    ret = vhost_dev_start(&b->dev, b->vdev);
> > > > +    if (ret < 0) {
> > > > +        error_report("Error start vhost dev");
> > > > +        goto err_guest_notifiers;
> > > > +    }
> > > > +
> > > > +    /* guest_notifier_mask/pending not used yet, so just unmask
> > > > +     * everything here.  virtio-pci will do the right thing by
> > > > +     * enabling/disabling irqfd.
> > > > +     */
> > > > +    for (i = 0; i < b->dev.nvqs; i++) {
> > > > +        vhost_virtqueue_mask(&b->dev, b->vdev,
> > > > +                             b->dev.vq_index + i, false);
> > > > +    }
> > > > +
> > > > +    b->started = true;
> > > > +    return;
> > > > +
> > > > +err_guest_notifiers:
> > > > +    k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
> > > > +err_host_notifiers:
> > > > +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> > > > +}
> > > > +
> > > > +void
> > > > +vhost_user_backend_stop(VhostUserBackend *b)
> > > > +{
> > > > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> > > > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > > > +    int ret = 0;
> > > > +
> > > > +    if (!b->started) {
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    vhost_dev_stop(&b->dev, b->vdev);
> > > > +
> > > > +    if (k->set_guest_notifiers) {
> > > > +        ret = k->set_guest_notifiers(qbus->parent,
> > > > +                                     b->dev.nvqs, false);
> > > > +        if (ret < 0) {
> > > > +            error_report("vhost guest notifier cleanup failed: %d", ret);
> > > > +        }
> > > > +    }
> > > > +    assert(ret >= 0);
> > > > +
> > > > +    vhost_dev_disable_notifiers(&b->dev, b->vdev);
> > > > +    b->started = false;
> > > > +}
> > > > +
> > > > +static void
> > > > +vhost_user_backend_complete(UserCreatable *uc, Error **errp)
> > > > +{
> > > > +    VhostUserBackend *b = VHOST_USER_BACKEND(uc);
> > > > +    Chardev *chr;
> > > > +
> > > > +    if (!b->chr_name) {
> > > > +        error_setg(errp, "You must specificy 'chardev'.");
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    chr = qemu_chr_find(b->chr_name);
> > > > +    if (chr == NULL) {
> > > > +        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> > > > +                  "Chardev '%s' not found", b->chr_name);
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    b->completed = true;
> > > > +    /* could vhost_dev_init() happen here, so early vhost-user message
> > > > +     * can be exchanged */
> > > > +}
> > > > +
> > > > +static void set_chardev(Object *obj, const char *value, Error **errp)
> > > > +{
> > > > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > > > +
> > > > +    if (b->completed) {
> > > > +        error_setg(errp, QERR_PERMISSION_DENIED);
> > > > +    } else {
> > > > +        g_free(b->chr_name);
> > > > +        b->chr_name = g_strdup(value);
> > > > +    }
> > > > +}
> > > > +
> > > > +static char *get_chardev(Object *obj, Error **errp)
> > > > +{
> > > > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > > > +    Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
> > > > +
> > > > +    if (chr && chr->label) {
> > > > +        return g_strdup(chr->label);
> > > > +    }
> > > > +
> > > > +    return NULL;
> > > > +}
> > > > +
> > > > +static void vhost_user_backend_init(Object *obj)
> > > > +{
> > > > +    object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
> > > > +}
> > > > +
> > > > +static void vhost_user_backend_finalize(Object *obj)
> > > > +{
> > > > +    VhostUserBackend *b = VHOST_USER_BACKEND(obj);
> > > > +
> > > > +    g_free(b->dev.vqs);
> > > > +    g_free(b->chr_name);
> > > > +
> > > > +    vhost_user_cleanup(&b->vhost_user);
> > > > +    qemu_chr_fe_deinit(&b->chr, true);
> > > > +
> > > > +    if (b->child) {
> > > > +        object_unref(OBJECT(b->child));
> > > > +    }
> > > > +}
> > > > +
> > > > +static bool
> > > > +vhost_user_backend_can_be_deleted(UserCreatable *uc)
> > > > +{
> > > > +    return true;
> > > > +}
> > > > +
> > > > +static void
> > > > +vhost_user_backend_class_init(ObjectClass *oc, void *data)
> > > > +{
> > > > +    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
> > > > +
> > > > +    ucc->complete = vhost_user_backend_complete;
> > > > +    ucc->can_be_deleted = vhost_user_backend_can_be_deleted;
> > > > +}
> > > > +
> > > > +static const TypeInfo vhost_user_backend_info = {
> > > > +    .name = TYPE_VHOST_USER_BACKEND,
> > > > +    .parent = TYPE_OBJECT,
> > > > +    .instance_size = sizeof(VhostUserBackend),
> > > > +    .instance_init = vhost_user_backend_init,
> > > > +    .instance_finalize = vhost_user_backend_finalize,
> > > > +    .class_size = sizeof(VhostUserBackendClass),
> > > > +    .class_init = vhost_user_backend_class_init,
> > > > +    .interfaces = (InterfaceInfo[]) {
> > > > +        { TYPE_USER_CREATABLE },
> > > > +        { }
> > > > +    }
> > > > +};
> > > > +
> > > > +static void register_types(void)
> > > > +{
> > > > +    type_register_static(&vhost_user_backend_info);
> > > > +}
> > > > +
> > > > +type_init(register_types);
> > > > diff --git a/vl.c b/vl.c
> > > > index 9e4dba7f92..43012ee6a3 100644
> > > > --- a/vl.c
> > > > +++ b/vl.c
> > > > @@ -2784,7 +2784,8 @@ static bool object_create_initial(const char *type, QemuOpts *opts)
> > > >      }
> > > >
> > > >  #if defined(CONFIG_VHOST_USER) && defined(CONFIG_LINUX)
> > > > -    if (g_str_equal(type, "cryptodev-vhost-user")) {
> > > > +    if (g_str_equal(type, "cryptodev-vhost-user") ||
> > > > +        g_str_equal(type, "vhost-user-backend")) {
> > > >          return false;
> > > >      }
> > > >  #endif
> > > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > > index 16b6264412..e077fe788d 100644
> > > > --- a/MAINTAINERS
> > > > +++ b/MAINTAINERS
> > > > @@ -1424,6 +1424,8 @@ F: hw/*/*vhost*
> > > >  F: docs/interop/vhost-user.json
> > > >  F: docs/interop/vhost-user.txt
> > > >  F: contrib/vhost-user-*/
> > > > +F: backends/vhost-user.c
> > > > +F: include/sysemu/vhost-user-backend.h
> > > >
> > > >  virtio
> > > >  M: Michael S. Tsirkin <mst@redhat.com>
> > > > diff --git a/backends/Makefile.objs b/backends/Makefile.objs
> > > > index 717fcbdae4..a5ec0bf907 100644
> > > > --- a/backends/Makefile.objs
> > > > +++ b/backends/Makefile.objs
> > > > @@ -12,7 +12,8 @@ common-obj-y += cryptodev-builtin.o
> > > >  ifeq ($(CONFIG_VIRTIO),y)
> > > >  common-obj-y += cryptodev-vhost.o
> > > >  common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += \
> > > > -    cryptodev-vhost-user.o
> > > > +    cryptodev-vhost-user.o \
> > > > +    vhost-user.o
> > > >  endif
> > > >
> > > >  common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
> > > > diff --git a/qemu-options.hx b/qemu-options.hx
> > > > index 06ef1a7c5c..24315a4cda 100644
> > > > --- a/qemu-options.hx
> > > > +++ b/qemu-options.hx
> > > > @@ -4203,6 +4203,26 @@ secondary:
> > > >  If you want to know the detail of above command line, you can read
> > > >  the colo-compare git log.
> > > >
> > > > +@item -object vhost-user-backend,id=id=@var{id},chardev=@var{chardevid}
> > > > +
> > > > +Create a vhost-user-backend object that holds a connection to a
> > > > +vhost-user backend and can be referenced from virtio/vhost-user
> > > > +devices that support it.
> > > > +
> > > > +The @var{id} parameter is a unique ID that will be used to reference
> > > > +this vhost-user backend from the @option{vhost-user} device. The
> > > > +@var{chardev} parameter is the unique ID of a character device backend
> > > > +that provides the connection to the vhost-user slave process. (Since 3.2)
> > > > +
> > > > +@example
> > > > +
> > > > + # qemu-system-x86_64 \
> > > > +   [...] \
> > > > +   -object vhost-user-backend,id=vuid,chardev=char0 \
> > > > +   -device vhost-user-input-pci,vhost-user=vuid
> > > > +   [...]
> > > > +@end example
> > > > +
> > > >  @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
> > > >
> > > >  Creates a cryptodev backend which executes crypto opreation from
> > > > --
> > > > 2.20.1.519.g8feddda32c
>


-- 
Marc-André Lureau

^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2019-02-08 11:15 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-02-07 16:54 [Qemu-devel] [PATCH v2 00/12] vhost-user-backend & vhost-user-input Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 01/12] vhost-user: define conventions for vhost-user backends Marc-André Lureau
2019-02-07 17:42   ` Eric Blake
2019-02-07 18:45     ` Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 02/12] vhost-user: simplify vhost_user_init/vhost_user_cleanup Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 03/12] libvhost-user: exit by default on VHOST_USER_NONE Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 04/12] vhost-user: wrap some read/write with retry handling Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 05/12] Add vhost-user-backend Marc-André Lureau
2019-02-07 17:36   ` Michael S. Tsirkin
2019-02-07 18:29     ` Marc-André Lureau
2019-02-07 19:18       ` Michael S. Tsirkin
2019-02-08 11:15         ` Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 06/12] vhost-user: split vhost_user_read() Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 07/12] vhost-user: add vhost_user_input_get_config() Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 08/12] libvhost-user-glib: export vug_source_new() Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 09/12] libvhost-user: add vu_queue_unpop() Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 10/12] Add vhost-user-input-pci Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 11/12] contrib: add vhost-user-input Marc-André Lureau
2019-02-07 16:54 ` [Qemu-devel] [PATCH v2 12/12] RFC: add explicit can_migrate to vhost_user_backend_dev_init() Marc-André Lureau

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