[v4,04/14] vfio-user: define vfio-user-server object

Commit Message

Jag Raman Dec. 15, 2021, 3:35 p.m. UTC

Define vfio-user object which is remote process server for QEMU. Setup
object initialization functions and properties necessary to instantiate
the object

Signed-off-by: Elena Ufimtseva <[e-mail]>
Signed-off-by: John G Johnson <[e-mail]>
Signed-off-by: Jagannathan Raman <[e-mail]>
---
 qapi/qom.json             |  20 ++++-
 hw/remote/vfio-user-obj.c | 175 ++++++++++++++++++++++++++++++++++++++
 MAINTAINERS               |   1 +
 hw/remote/meson.build     |   1 +
 hw/remote/trace-events    |   3 +
 5 files changed, 198 insertions(+), 2 deletions(-)
 create mode 100644 hw/remote/vfio-user-obj.c

Comments

Stefan Hajnoczi Dec. 16, 2021, 9:33 a.m. UTC | #1

On Wed, Dec 15, 2021 at 10:35:28AM -0500, Jagannathan Raman wrote:
> diff --git a/qapi/qom.json b/qapi/qom.json
> index ccd1167808..6001a9b8f0 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -703,6 +703,20 @@
>  { 'struct': 'RemoteObjectProperties',
>    'data': { 'fd': 'str', 'devid': 'str' } }
>  
> +##
> +# @VfioUserServerProperties:
> +#
> +# Properties for x-vfio-user-server objects.
> +#
> +# @socket: socket to be used by the libvfiouser library
> +#
> +# @device: the id of the device to be emulated at the server
> +#
> +# Since: 6.2

6.2 has been released so the version number needs to be incremented.

> +struct VfuObjectClass {
> +    ObjectClass parent_class;
> +
> +    unsigned int nr_devs;
> +
> +    bool daemon;

I was wondering what this means. auto_shutdown might be a clearer name.

> +static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
> +                                  void *opaque, Error **errp)
> +{
> +    VfuObject *o = VFU_OBJECT(obj);
> +
> +    qapi_free_SocketAddress(o->socket);
> +
> +    o->socket = NULL;
> +
> +    visit_type_SocketAddress(v, name, &o->socket, errp);
> +
> +    if (o->socket->type != SOCKET_ADDRESS_TYPE_UNIX) {
> +        qapi_free_SocketAddress(o->socket);
> +        o->socket = NULL;
> +        error_setg(errp, "vfu: Unsupported socket type - %s",
> +                   o->socket->u.q_unix.path);

s/o->socket->u.q_unix.path/SocketAddressType_str(o->socket->type)/

Stefan Hajnoczi Dec. 16, 2021, 9:58 a.m. UTC | #2

On Wed, Dec 15, 2021 at 10:35:28AM -0500, Jagannathan Raman wrote:
> +static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
> +                                  void *opaque, Error **errp)
> +{
> +    VfuObject *o = VFU_OBJECT(obj);
> +
> +    qapi_free_SocketAddress(o->socket);
> +
> +    o->socket = NULL;
> +
> +    visit_type_SocketAddress(v, name, &o->socket, errp);
> +
> +    if (o->socket->type != SOCKET_ADDRESS_TYPE_UNIX) {
> +        qapi_free_SocketAddress(o->socket);
> +        o->socket = NULL;
> +        error_setg(errp, "vfu: Unsupported socket type - %s",
> +                   o->socket->u.q_unix.path);
> +        return;
> +    }
> +
> +    trace_vfu_prop("socket", o->socket->u.q_unix.path);
> +}
> +
> +static void vfu_object_set_device(Object *obj, const char *str, Error **errp)
> +{
> +    VfuObject *o = VFU_OBJECT(obj);
> +
> +    g_free(o->device);
> +
> +    o->device = g_strdup(str);
> +
> +    trace_vfu_prop("device", str);
> +}

It appears "socket" and "device" can be changed after the
vfio-user server has started. In the best case it just means the
properties contain values that do not reflect the actual socket/device
currently in use, which is confusing.

It's safer to refuse changing these properties once the vfio-user
server has started.

Stefan

Jag Raman Dec. 17, 2021, 2:17 a.m. UTC | #3

> On Dec 16, 2021, at 4:33 AM, Stefan Hajnoczi <[e-mail]> wrote:
> 
> On Wed, Dec 15, 2021 at 10:35:28AM -0500, Jagannathan Raman wrote:
>> diff --git a/qapi/qom.json b/qapi/qom.json
>> index ccd1167808..6001a9b8f0 100644
>> --- a/qapi/qom.json
>> +++ b/qapi/qom.json
>> @@ -703,6 +703,20 @@
>> { 'struct': 'RemoteObjectProperties',
>>   'data': { 'fd': 'str', 'devid': 'str' } }
>> 
>> +##
>> +# @VfioUserServerProperties:
>> +#
>> +# Properties for x-vfio-user-server objects.
>> +#
>> +# @socket: socket to be used by the libvfiouser library
>> +#
>> +# @device: the id of the device to be emulated at the server
>> +#
>> +# Since: 6.2
> 
> 6.2 has been released so the version number needs to be incremented.

OK, thanks!

> 
>> +struct VfuObjectClass {
>> +    ObjectClass parent_class;
>> +
>> +    unsigned int nr_devs;
>> +
>> +    bool daemon;
> 
> I was wondering what this means. auto_shutdown might be a clearer name.

Sure, will do. 

> 
>> +static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
>> +                                  void *opaque, Error **errp)
>> +{
>> +    VfuObject *o = VFU_OBJECT(obj);
>> +
>> +    qapi_free_SocketAddress(o->socket);
>> +
>> +    o->socket = NULL;
>> +
>> +    visit_type_SocketAddress(v, name, &o->socket, errp);
>> +
>> +    if (o->socket->type != SOCKET_ADDRESS_TYPE_UNIX) {
>> +        qapi_free_SocketAddress(o->socket);
>> +        o->socket = NULL;
>> +        error_setg(errp, "vfu: Unsupported socket type - %s",
>> +                   o->socket->u.q_unix.path);
> 
> s/o->socket->u.q_unix.path/SocketAddressType_str(o->socket->type)/

Ok, got it.

Thanks!
--
Jag

Jag Raman Dec. 17, 2021, 2:31 a.m. UTC | #4

> On Dec 16, 2021, at 4:58 AM, Stefan Hajnoczi <[e-mail]> wrote:
> 
> On Wed, Dec 15, 2021 at 10:35:28AM -0500, Jagannathan Raman wrote:
>> +static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
>> +                                  void *opaque, Error **errp)
>> +{
>> +    VfuObject *o = VFU_OBJECT(obj);
>> +
>> +    qapi_free_SocketAddress(o->socket);
>> +
>> +    o->socket = NULL;
>> +
>> +    visit_type_SocketAddress(v, name, &o->socket, errp);
>> +
>> +    if (o->socket->type != SOCKET_ADDRESS_TYPE_UNIX) {
>> +        qapi_free_SocketAddress(o->socket);
>> +        o->socket = NULL;
>> +        error_setg(errp, "vfu: Unsupported socket type - %s",
>> +                   o->socket->u.q_unix.path);
>> +        return;
>> +    }
>> +
>> +    trace_vfu_prop("socket", o->socket->u.q_unix.path);
>> +}
>> +
>> +static void vfu_object_set_device(Object *obj, const char *str, Error **errp)
>> +{
>> +    VfuObject *o = VFU_OBJECT(obj);
>> +
>> +    g_free(o->device);
>> +
>> +    o->device = g_strdup(str);
>> +
>> +    trace_vfu_prop("device", str);
>> +}
> 
> It appears "socket" and "device" can be changed after the
> vfio-user server has started. In the best case it just means the
> properties contain values that do not reflect the actual socket/device
> currently in use, which is confusing.

I’m not sure about the scenario in which that would occur, but will add that check.

Thank you!
--
Jag

> 
> It's safer to refuse changing these properties once the vfio-user
> server has started.
> 
> Stefan

Stefan Hajnoczi Dec. 17, 2021, 8:28 a.m. UTC | #5

On Fri, Dec 17, 2021 at 02:31:14AM +0000, Jag Raman wrote:
> 
> 
> > On Dec 16, 2021, at 4:58 AM, Stefan Hajnoczi <[e-mail]> wrote:
> > 
> > On Wed, Dec 15, 2021 at 10:35:28AM -0500, Jagannathan Raman wrote:
> >> +static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
> >> +                                  void *opaque, Error **errp)
> >> +{
> >> +    VfuObject *o = VFU_OBJECT(obj);
> >> +
> >> +    qapi_free_SocketAddress(o->socket);
> >> +
> >> +    o->socket = NULL;
> >> +
> >> +    visit_type_SocketAddress(v, name, &o->socket, errp);
> >> +
> >> +    if (o->socket->type != SOCKET_ADDRESS_TYPE_UNIX) {
> >> +        qapi_free_SocketAddress(o->socket);
> >> +        o->socket = NULL;
> >> +        error_setg(errp, "vfu: Unsupported socket type - %s",
> >> +                   o->socket->u.q_unix.path);
> >> +        return;
> >> +    }
> >> +
> >> +    trace_vfu_prop("socket", o->socket->u.q_unix.path);
> >> +}
> >> +
> >> +static void vfu_object_set_device(Object *obj, const char *str, Error **errp)
> >> +{
> >> +    VfuObject *o = VFU_OBJECT(obj);
> >> +
> >> +    g_free(o->device);
> >> +
> >> +    o->device = g_strdup(str);
> >> +
> >> +    trace_vfu_prop("device", str);
> >> +}
> > 
> > It appears "socket" and "device" can be changed after the
> > vfio-user server has started. In the best case it just means the
> > properties contain values that do not reflect the actual socket/device
> > currently in use, which is confusing.
> 
> I’m not sure about the scenario in which that would occur, but will add that check.

Properties can be modified using the qom-set monitor command. This can
happen any time.

Stefan

Patch

diff --git a/qapi/qom.json b/qapi/qom.json
index ccd1167808..6001a9b8f0 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -703,6 +703,20 @@ 
 { 'struct': 'RemoteObjectProperties',
   'data': { 'fd': 'str', 'devid': 'str' } }
 
+##
+# @VfioUserServerProperties:
+#
+# Properties for x-vfio-user-server objects.
+#
+# @socket: socket to be used by the libvfiouser library
+#
+# @device: the id of the device to be emulated at the server
+#
+# Since: 6.2
+##
+{ 'struct': 'VfioUserServerProperties',
+  'data': { 'socket': 'SocketAddress', 'device': 'str' } }
+
 ##
 # @RngProperties:
 #
@@ -837,7 +851,8 @@ 
     'tls-creds-psk',
     'tls-creds-x509',
     'tls-cipher-suites',
-    { 'name': 'x-remote-object', 'features': [ 'unstable' ] }
+    { 'name': 'x-remote-object', 'features': [ 'unstable' ] },
+    { 'name': 'x-vfio-user-server', 'features': [ 'unstable' ] }
   ] }
 
 ##
@@ -900,7 +915,8 @@ 
       'tls-creds-psk':              'TlsCredsPskProperties',
       'tls-creds-x509':             'TlsCredsX509Properties',
       'tls-cipher-suites':          'TlsCredsProperties',
-      'x-remote-object':            'RemoteObjectProperties'
+      'x-remote-object':            'RemoteObjectProperties',
+      'x-vfio-user-server':         'VfioUserServerProperties'
   } }
 
 ##
diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c
new file mode 100644
index 0000000000..10296ef33c
--- /dev/null
+++ b/hw/remote/vfio-user-obj.c
@@ -0,0 +1,175 @@ 
+/**
+ * QEMU vfio-user-server server object
+ *
+ * Copyright © 2021 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL-v2, version 2 or later.
+ *
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+/**
+ * Usage: add options:
+ *     -machine x-remote
+ *     -device <PCI-device>,id=<pci-dev-id>
+ *     -object x-vfio-user-server,id=<id>,type=unix,path=<socket-path>,
+ *             device=<pci-dev-id>
+ *
+ * Note that x-vfio-user-server object must be used with x-remote machine only.
+ * This server could only support PCI devices for now.
+ *
+ * type - SocketAddress type - presently "unix" alone is supported. Required
+ *        option
+ *
+ * path - named unix socket, it will be created by the server. It is
+ *        a required option
+ *
+ * device - id of a device on the server, a required option. PCI devices
+ *          alone are supported presently.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+
+#include "qom/object.h"
+#include "qom/object_interfaces.h"
+#include "qemu/error-report.h"
+#include "trace.h"
+#include "sysemu/runstate.h"
+#include "hw/boards.h"
+#include "hw/remote/machine.h"
+#include "qapi/error.h"
+#include "qapi/qapi-visit-sockets.h"
+
+#define TYPE_VFU_OBJECT "x-vfio-user-server"
+OBJECT_DECLARE_TYPE(VfuObject, VfuObjectClass, VFU_OBJECT)
+
+struct VfuObjectClass {
+    ObjectClass parent_class;
+
+    unsigned int nr_devs;
+
+    bool daemon;
+};
+
+struct VfuObject {
+    /* private */
+    Object parent;
+
+    SocketAddress *socket;
+
+    char *device;
+
+    Error *err;
+};
+
+static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
+                                  void *opaque, Error **errp)
+{
+    VfuObject *o = VFU_OBJECT(obj);
+
+    qapi_free_SocketAddress(o->socket);
+
+    o->socket = NULL;
+
+    visit_type_SocketAddress(v, name, &o->socket, errp);
+
+    if (o->socket->type != SOCKET_ADDRESS_TYPE_UNIX) {
+        qapi_free_SocketAddress(o->socket);
+        o->socket = NULL;
+        error_setg(errp, "vfu: Unsupported socket type - %s",
+                   o->socket->u.q_unix.path);
+        return;
+    }
+
+    trace_vfu_prop("socket", o->socket->u.q_unix.path);
+}
+
+static void vfu_object_set_device(Object *obj, const char *str, Error **errp)
+{
+    VfuObject *o = VFU_OBJECT(obj);
+
+    g_free(o->device);
+
+    o->device = g_strdup(str);
+
+    trace_vfu_prop("device", str);
+}
+
+static void vfu_object_init(Object *obj)
+{
+    VfuObjectClass *k = VFU_OBJECT_GET_CLASS(obj);
+    VfuObject *o = VFU_OBJECT(obj);
+
+    k->nr_devs++;
+
+    if (!object_dynamic_cast(OBJECT(current_machine), TYPE_REMOTE_MACHINE)) {
+        error_setg(&o->err, "vfu: %s only compatible with %s machine",
+                   TYPE_VFU_OBJECT, TYPE_REMOTE_MACHINE);
+        return;
+    }
+}
+
+static void vfu_object_finalize(Object *obj)
+{
+    VfuObjectClass *k = VFU_OBJECT_GET_CLASS(obj);
+    VfuObject *o = VFU_OBJECT(obj);
+
+    k->nr_devs--;
+
+    qapi_free_SocketAddress(o->socket);
+
+    o->socket = NULL;
+
+    g_free(o->device);
+
+    o->device = NULL;
+
+    if (!k->nr_devs && !k->daemon) {
+        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
+    }
+}
+
+static void vfu_object_class_init(ObjectClass *klass, void *data)
+{
+    VfuObjectClass *k = VFU_OBJECT_CLASS(klass);
+
+    k->nr_devs = 0;
+
+    /* Later determine how to detect a daemon */
+    k->daemon = false;
+
+    object_class_property_add(klass, "socket", "SocketAddress", NULL,
+                              vfu_object_set_socket, NULL, NULL);
+    object_class_property_set_description(klass, "socket",
+                                          "SocketAddress "
+                                          "(ex: type=unix,path=/tmp/sock). "
+                                          "Only UNIX is presently supported");
+    object_class_property_add_str(klass, "device", NULL,
+                                  vfu_object_set_device);
+    object_class_property_set_description(klass, "device",
+                                          "device ID - only PCI devices "
+                                          "are presently supported");
+}
+
+static const TypeInfo vfu_object_info = {
+    .name = TYPE_VFU_OBJECT,
+    .parent = TYPE_OBJECT,
+    .instance_size = sizeof(VfuObject),
+    .instance_init = vfu_object_init,
+    .instance_finalize = vfu_object_finalize,
+    .class_size = sizeof(VfuObjectClass),
+    .class_init = vfu_object_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+static void vfu_register_types(void)
+{
+    type_register_static(&vfu_object_info);
+}
+
+type_init(vfu_register_types);
diff --git a/MAINTAINERS b/MAINTAINERS
index e0daf349ae..b5eb306662 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3465,6 +3465,7 @@  F: include/hw/remote/proxy-memory-listener.h
 F: hw/remote/iohub.c
 F: include/hw/remote/iohub.h
 F: subprojects/libvfio-user
+F: hw/remote/vfio-user-obj.c
 
 EBPF:
 M: Jason Wang <[e-mail]>
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index dfea6b533b..534ac5df79 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -6,6 +6,7 @@  remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('iohub.c'))
+remote_ss.add(when: 'CONFIG_VFIO_USER_SERVER', if_true: files('vfio-user-obj.c'))
 
 remote_ss.add(when: 'CONFIG_VFIO_USER_SERVER', if_true: vfiouser)
 
diff --git a/hw/remote/trace-events b/hw/remote/trace-events
index 0b23974f90..7da12f0d96 100644
--- a/hw/remote/trace-events
+++ b/hw/remote/trace-events
@@ -2,3 +2,6 @@ 
 
 mpqemu_send_io_error(int cmd, int size, int nfds) "send command %d size %d, %d file descriptors to remote process"
 mpqemu_recv_io_error(int cmd, int size, int nfds) "failed to receive %d size %d, %d file descriptors to remote process"
+
+# vfio-user-obj.c
+vfu_prop(const char *prop, const char *val) "vfu: setting %s as %s"