qmp: add QMP command x-query-virtio

This new command lists all the instances of VirtIODevices with
their canonical QOM path and name.

[Jonah: @virtio_list duplicates information that already exists in
 the QOM composition tree. However, extracting necessary information
 from this tree seems to be a bit convoluted.

 Instead, we still create our own list of realized virtio devices
 but use @qmp_qom_get with the device's canonical QOM path to confirm
 that the device exists and is realized. If the device exists but
 is actually not realized, then we remove it from our list (for
 synchronicity to the QOM composition tree).

 Also, the QMP command @x-query-virtio is redundant as @qom-list
 and @qom-get are sufficient to search '/machine/' for realized
 virtio devices. However, @x-query-virtio is much more convenient
 in listing realized virtio devices.]

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Message-Id: <1660220684-24909-2-git-send-email-jonah.palmer@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index c14e3db10a629ab2eff621932373d9bbb015b2b2..dfed1e7af598d19bc5947434d8298c6c8b71078c 100644 (file)
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -62,4 +62,6 @@ virtio_ss.add_all(when: 'CONFIG_VIRTIO_PCI', if_true: virtio_pci_ss)
 specific_ss.add_all(when: 'CONFIG_VIRTIO', if_true: virtio_ss)
 softmmu_ss.add_all(when: 'CONFIG_VIRTIO', if_true: softmmu_virtio_ss)
 softmmu_ss.add(when: 'CONFIG_VIRTIO', if_false: files('vhost-stub.c'))
+softmmu_ss.add(when: 'CONFIG_VIRTIO', if_false: files('virtio-stub.c'))
 softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('vhost-stub.c'))
+softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('virtio-stub.c'))

diff --git a/hw/virtio/virtio-stub.c b/hw/virtio/virtio-stub.c
new file mode 100644 (file)
index 0000000..05a81ed
--- /dev/null
+++ b/hw/virtio/virtio-stub.c
@@ -0,0 +1,14 @@
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-virtio.h"
+
+static void *qmp_virtio_unsupported(Error **errp)
+{
+    error_setg(errp, "Virtio is disabled");
+    return NULL;
+}
+
+VirtioInfoList *qmp_x_query_virtio(Error **errp)
+{
+    return qmp_virtio_unsupported(errp);
+}

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 2cc1d7d24a52296997b004d06d7ac3e44e422981..4fc7c80d3fd077961030a671a0686f25741d7da3 100644 (file)
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -13,12 +13,18 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qapi-commands-virtio.h"
+#include "qapi/qapi-commands-qom.h"
+#include "qapi/qapi-visit-virtio.h"
+#include "qapi/qmp/qjson.h"
 #include "cpu.h"
 #include "trace.h"
 #include "qemu/error-report.h"
 #include "qemu/log.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
+#include "qom/object_interfaces.h"
 #include "hw/virtio/virtio.h"
 #include "migration/qemu-file-types.h"
 #include "qemu/atomic.h"
@@ -29,6 +35,9 @@
 #include "sysemu/runstate.h"
 #include "standard-headers/linux/virtio_ids.h"
 
+/* QAPI list of realized VirtIODevices */
+static QTAILQ_HEAD(, VirtIODevice) virtio_list;
+
 /*
  * The alignment to use between consumer and producer parts of vring.
  * x86 pagesize again. This is the default, used by transports like PCI
@@ -3707,6 +3716,7 @@ static void virtio_device_realize(DeviceState *dev, Error **errp)
     vdev->listener.commit = virtio_memory_listener_commit;
     vdev->listener.name = "virtio";
     memory_listener_register(&vdev->listener, vdev->dma_as);
+    QTAILQ_INSERT_TAIL(&virtio_list, vdev, next);
 }
 
 static void virtio_device_unrealize(DeviceState *dev)
@@ -3721,6 +3731,7 @@ static void virtio_device_unrealize(DeviceState *dev)
         vdc->unrealize(dev);
     }
 
+    QTAILQ_REMOVE(&virtio_list, vdev, next);
     g_free(vdev->bus_name);
     vdev->bus_name = NULL;
 }
@@ -3894,6 +3905,8 @@ static void virtio_device_class_init(ObjectClass *klass, void *data)
     vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
 
     vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
+
+    QTAILQ_INIT(&virtio_list);
 }
 
 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
@@ -3904,6 +3917,37 @@ bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
     return virtio_bus_ioeventfd_enabled(vbus);
 }
 
+VirtioInfoList *qmp_x_query_virtio(Error **errp)
+{
+    VirtioInfoList *list = NULL;
+    VirtioInfoList *node;
+    VirtIODevice *vdev;
+
+    QTAILQ_FOREACH(vdev, &virtio_list, next) {
+        DeviceState *dev = DEVICE(vdev);
+        Error *err = NULL;
+        QObject *obj = qmp_qom_get(dev->canonical_path, "realized", &err);
+
+        if (err == NULL) {
+            GString *is_realized = qobject_to_json_pretty(obj, true);
+            /* virtio device is NOT realized, remove it from list */
+            if (!strncmp(is_realized->str, "false", 4)) {
+                QTAILQ_REMOVE(&virtio_list, vdev, next);
+            } else {
+                node = g_new0(VirtioInfoList, 1);
+                node->value = g_new(VirtioInfo, 1);
+                node->value->path = g_strdup(dev->canonical_path);
+                node->value->name = g_strdup(vdev->name);
+                QAPI_LIST_PREPEND(list, node->value);
+            }
+           g_string_free(is_realized, true);
+        }
+        qobject_unref(obj);
+    }
+
+    return list;
+}
+
 static const TypeInfo virtio_device_info = {
     .name = TYPE_VIRTIO_DEVICE,
     .parent = TYPE_DEVICE,

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index cecfb7c5526949f75e2c61c44f29c373dc520223..9eeb958e39f1ec181292af15f2c233705db83384 100644 (file)
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -122,6 +122,7 @@ struct VirtIODevice
     bool use_guest_notifier_mask;
     AddressSpace *dma_as;
     QLIST_HEAD(, VirtQueue) *vector_queues;
+    QTAILQ_ENTRY(VirtIODevice) next;
 };
 
 struct VirtioDeviceClass {

diff --git a/qapi/meson.build b/qapi/meson.build
index 840f1b0e195229c2c298f61b2f54df48a14dd791..9a36c15c0456b3238cb44424f5eb9d9baf20279a 100644 (file)
--- a/qapi/meson.build
+++ b/qapi/meson.build
@@ -49,6 +49,7 @@ qapi_all_modules = [
   'stats',
   'trace',
   'transaction',
+  'virtio',
   'yank',
 ]
 if have_system

diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json
index 92d7ecc52c5893c8dc5162b8618ec9ca279e3439..f000b90744fa7409475e1db1dfa9410ec087ed85 100644 (file)
--- a/qapi/qapi-schema.json
+++ b/qapi/qapi-schema.json
@@ -94,3 +94,4 @@
 { 'include': 'acpi.json' }
 { 'include': 'pci.json' }
 { 'include': 'stats.json' }
+{ 'include': 'virtio.json' }

diff --git a/qapi/virtio.json b/qapi/virtio.json
new file mode 100644 (file)
index 0000000..03896e4
--- /dev/null
+++ b/qapi/virtio.json
@@ -0,0 +1,68 @@
+# -*- Mode: Python -*-
+# vim: filetype=python
+#
+
+##
+# = Virtio devices
+##
+
+##
+# @VirtioInfo:
+#
+# Basic information about a given VirtIODevice
+#
+# @path: The VirtIODevice's canonical QOM path
+#
+# @name: Name of the VirtIODevice
+#
+# Since: 7.1
+#
+##
+{ 'struct': 'VirtioInfo',
+  'data': { 'path': 'str',
+            'name': 'str' } }
+
+##
+# @x-query-virtio:
+#
+# Returns a list of all realized VirtIODevices
+#
+# Features:
+# @unstable: This command is meant for debugging.
+#
+# Returns: List of gathered VirtIODevices
+#
+# Since: 7.1
+#
+# Example:
+#
+# -> { "execute": "x-query-virtio" }
+# <- { "return": [
+#          {
+#              "name": "virtio-input",
+#              "path": "/machine/peripheral-anon/device[4]/virtio-backend"
+#          },
+#          {
+#              "name": "virtio-crypto",
+#              "path": "/machine/peripheral/crypto0/virtio-backend"
+#          },
+#          {
+#              "name": "virtio-scsi",
+#              "path": "/machine/peripheral-anon/device[2]/virtio-backend"
+#          },
+#          {
+#              "name": "virtio-net",
+#              "path": "/machine/peripheral-anon/device[1]/virtio-backend"
+#          },
+#          {
+#              "name": "virtio-serial",
+#              "path": "/machine/peripheral-anon/device[0]/virtio-backend"
+#          }
+#      ]
+#    }
+#
+##
+
+{ 'command': 'x-query-virtio',
+  'returns': [ 'VirtioInfo' ],
+  'features': [ 'unstable' ] }

diff --git a/tests/qtest/qmp-cmd-test.c b/tests/qtest/qmp-cmd-test.c
index af0071245863768211ab44b883ddde0b93bc3774..897e4e937bd5e77f63450ba9e9c5c6bcd78e8ca7 100644 (file)
--- a/tests/qtest/qmp-cmd-test.c
+++ b/tests/qtest/qmp-cmd-test.c
@@ -103,6 +103,7 @@ static bool query_is_ignored(const char *cmd)
         "query-gic-capabilities", /* arm */
         /* Success depends on target-specific build configuration: */
         "query-pci",              /* CONFIG_PCI */
+        "x-query-virtio",         /* CONFIG_VIRTIO */
         /* Success depends on launching SEV guest */
         "query-sev-launch-measure",
         /* Success depends on Host or Hypervisor SEV support */