[PATCH v6 3/6] qmp: decode feature bits in virtio-status

[Jonah Palmer <jonah.palmer@oracle.com>]

From: Laurent Vivier <lvivier@redhat.com>

Display feature names instead of a features bitmap for host, guest,
and backend.

Decode features according to device type, transport features are
on the first line. Undecoded bits (if any) are stored in a separate
field.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
 hw/block/virtio-blk.c        |  23 ++++
 hw/char/virtio-serial-bus.c  |  11 ++
 hw/display/virtio-gpu-base.c |  12 ++
 hw/net/virtio-net.c          |  38 ++++++
 hw/scsi/virtio-scsi.c        |  12 ++
 hw/virtio/virtio-balloon.c   |  14 +++
 hw/virtio/virtio-iommu.c     |  14 +++
 hw/virtio/virtio.c           | 129 +++++++++++++++++++-
 include/hw/virtio/virtio.h   |  13 ++
 qapi/virtio.json             | 280 +++++++++++++++++++++++++++++++++++++++++--
 10 files changed, 533 insertions(+), 13 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index f139cd7..e66c5eb 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -13,6 +13,7 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "qemu/iov.h"
 #include "qemu/module.h"
 #include "qemu/error-report.h"
@@ -48,6 +49,28 @@ static const VirtIOFeature feature_sizes[] = {
     {}
 };
 
+qmp_virtio_feature_map_t blk_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_BLK_F_##name, VIRTIO_BLK_FEATURE_##name }
+    FEATURE_ENTRY(SIZE_MAX),
+    FEATURE_ENTRY(SEG_MAX),
+    FEATURE_ENTRY(GEOMETRY),
+    FEATURE_ENTRY(RO),
+    FEATURE_ENTRY(BLK_SIZE),
+    FEATURE_ENTRY(TOPOLOGY),
+    FEATURE_ENTRY(MQ),
+    FEATURE_ENTRY(DISCARD),
+    FEATURE_ENTRY(WRITE_ZEROES),
+#ifndef VIRTIO_BLK_NO_LEGACY
+    FEATURE_ENTRY(BARRIER),
+    FEATURE_ENTRY(SCSI),
+    FEATURE_ENTRY(FLUSH),
+    FEATURE_ENTRY(CONFIG_WCE),
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 static void virtio_blk_set_config_size(VirtIOBlock *s, uint64_t host_features)
 {
     s->config_size = MAX(VIRTIO_BLK_CFG_SIZE,
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index dd6bc27..4a626e6 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -20,6 +20,7 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "qemu/iov.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
@@ -32,6 +33,16 @@
 #include "hw/virtio/virtio-serial.h"
 #include "hw/virtio/virtio-access.h"
 
+qmp_virtio_feature_map_t serial_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_CONSOLE_F_##name, VIRTIO_SERIAL_FEATURE_##name }
+    FEATURE_ENTRY(SIZE),
+    FEATURE_ENTRY(MULTIPORT),
+    FEATURE_ENTRY(EMERG_WRITE),
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 static struct VirtIOSerialDevices {
     QLIST_HEAD(, VirtIOSerial) devices;
 } vserdevices;
diff --git a/hw/display/virtio-gpu-base.c b/hw/display/virtio-gpu-base.c
index dd29427..34c1ead 100644
--- a/hw/display/virtio-gpu-base.c
+++ b/hw/display/virtio-gpu-base.c
@@ -16,9 +16,21 @@
 #include "hw/virtio/virtio-gpu.h"
 #include "migration/blocker.h"
 #include "qapi/error.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "qemu/error-report.h"
 #include "trace.h"
 
+qmp_virtio_feature_map_t gpu_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_GPU_F_##name, VIRTIO_GPU_FEATURE_##name }
+    FEATURE_ENTRY(VIRGL),
+    FEATURE_ENTRY(EDID),
+    FEATURE_ENTRY(RESOURCE_UUID),
+    FEATURE_ENTRY(RESOURCE_BLOB),
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 void
 virtio_gpu_base_reset(VirtIOGPUBase *g)
 {
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 16d20cd..0a05fe6 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -35,6 +35,7 @@
 #include "hw/qdev-properties.h"
 #include "qapi/qapi-types-migration.h"
 #include "qapi/qapi-events-migration.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "hw/virtio/virtio-access.h"
 #include "migration/misc.h"
 #include "standard-headers/linux/ethtool.h"
@@ -89,6 +90,43 @@
                                          VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | \
                                          VIRTIO_NET_RSS_HASH_TYPE_UDP_EX)
 
+qmp_virtio_feature_map_t net_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_NET_F_##name, VIRTIO_NET_FEATURE_##name }
+    FEATURE_ENTRY(CSUM),
+    FEATURE_ENTRY(GUEST_CSUM),
+    FEATURE_ENTRY(CTRL_GUEST_OFFLOADS),
+    FEATURE_ENTRY(MTU),
+    FEATURE_ENTRY(MAC),
+    FEATURE_ENTRY(GUEST_TSO4),
+    FEATURE_ENTRY(GUEST_TSO6),
+    FEATURE_ENTRY(GUEST_ECN),
+    FEATURE_ENTRY(GUEST_UFO),
+    FEATURE_ENTRY(HOST_TSO4),
+    FEATURE_ENTRY(HOST_TSO6),
+    FEATURE_ENTRY(HOST_ECN),
+    FEATURE_ENTRY(HOST_UFO),
+    FEATURE_ENTRY(MRG_RXBUF),
+    FEATURE_ENTRY(STATUS),
+    FEATURE_ENTRY(CTRL_VQ),
+    FEATURE_ENTRY(CTRL_RX),
+    FEATURE_ENTRY(CTRL_VLAN),
+    FEATURE_ENTRY(CTRL_RX_EXTRA),
+    FEATURE_ENTRY(GUEST_ANNOUNCE),
+    FEATURE_ENTRY(MQ),
+    FEATURE_ENTRY(CTRL_MAC_ADDR),
+    FEATURE_ENTRY(HASH_REPORT),
+    FEATURE_ENTRY(RSS),
+    FEATURE_ENTRY(RSC_EXT),
+    FEATURE_ENTRY(STANDBY),
+    FEATURE_ENTRY(SPEED_DUPLEX),
+#ifndef VIRTIO_NET_NO_LEGACY
+    FEATURE_ENTRY(GSO),
+#endif /* VIRTIO_NET_NO_LEGACY */
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 static const VirtIOFeature feature_sizes[] = {
     {.flags = 1ULL << VIRTIO_NET_F_MAC,
      .end = endof(struct virtio_net_config, mac)},
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 6d80730..8187dc3 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -15,6 +15,7 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "standard-headers/linux/virtio_ids.h"
 #include "hw/virtio/virtio-scsi.h"
 #include "migration/qemu-file-types.h"
@@ -29,6 +30,17 @@
 #include "hw/virtio/virtio-access.h"
 #include "trace.h"
 
+qmp_virtio_feature_map_t scsi_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_SCSI_F_##name, VIRTIO_SCSI_FEATURE_##name }
+    FEATURE_ENTRY(INOUT),
+    FEATURE_ENTRY(HOTPLUG),
+    FEATURE_ENTRY(CHANGE),
+    FEATURE_ENTRY(T10_PI),
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 static inline int virtio_scsi_get_lun(uint8_t *lun)
 {
     return ((lun[2] << 8) | lun[3]) & 0x3FFF;
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 4b5d9e5..4bc05de 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -27,6 +27,7 @@
 #include "qapi/error.h"
 #include "qapi/qapi-events-machine.h"
 #include "qapi/visitor.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "trace.h"
 #include "qemu/error-report.h"
 #include "migration/misc.h"
@@ -34,6 +35,19 @@
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"
 
+qmp_virtio_feature_map_t balloon_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_BALLOON_F_##name, VIRTIO_BALLOON_FEATURE_##name }
+    FEATURE_ENTRY(MUST_TELL_HOST),
+    FEATURE_ENTRY(STATS_VQ),
+    FEATURE_ENTRY(DEFLATE_ON_OOM),
+    FEATURE_ENTRY(FREE_PAGE_HINT),
+    FEATURE_ENTRY(PAGE_POISON),
+    FEATURE_ENTRY(REPORTING),
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 #define BALLOON_PAGE_SIZE  (1 << VIRTIO_BALLOON_PFN_SHIFT)
 
 typedef struct PartiallyBalloonedPage {
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 1b23e8e..6deddcb 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -25,6 +25,7 @@
 #include "hw/virtio/virtio.h"
 #include "sysemu/kvm.h"
 #include "qapi/error.h"
+#include "qapi/qapi-visit-virtio.h"
 #include "qemu/error-report.h"
 #include "trace.h"
 
@@ -36,6 +37,19 @@
 #include "hw/pci/pci_bus.h"
 #include "hw/pci/pci.h"
 
+qmp_virtio_feature_map_t iommu_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_IOMMU_F_##name, VIRTIO_IOMMU_FEATURE_##name }
+    FEATURE_ENTRY(INPUT_RANGE),
+    FEATURE_ENTRY(DOMAIN_RANGE),
+    FEATURE_ENTRY(MAP_UNMAP),
+    FEATURE_ENTRY(BYPASS),
+    FEATURE_ENTRY(PROBE),
+    FEATURE_ENTRY(MMIO),
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 /* Max size */
 #define VIOMMU_DEFAULT_QUEUE_SIZE 256
 #define VIOMMU_PROBE_SIZE 512
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 222330a..81a0ee8 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -30,9 +30,32 @@
 #include "sysemu/dma.h"
 #include "sysemu/runstate.h"
 #include "standard-headers/linux/virtio_ids.h"
+#include CONFIG_DEVICES
 
 static QTAILQ_HEAD(, VirtIODevice) virtio_list;
 
+static qmp_virtio_feature_map_t transport_map[] = {
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_F_##name, VIRTIO_TRANSPORT_FEATURE_##name }
+#ifndef VIRTIO_CONFIG_NO_LEGACY
+    FEATURE_ENTRY(NOTIFY_ON_EMPTY),
+    FEATURE_ENTRY(ANY_LAYOUT),
+#endif /* VIRTIO_CONFIG_NO_LEGACY */
+    FEATURE_ENTRY(VERSION_1),
+    FEATURE_ENTRY(IOMMU_PLATFORM),
+    FEATURE_ENTRY(RING_PACKED),
+    FEATURE_ENTRY(ORDER_PLATFORM),
+    FEATURE_ENTRY(SR_IOV),
+    FEATURE_ENTRY(BAD_FEATURE),
+#undef FEATURE_ENTRY
+#define FEATURE_ENTRY(name) \
+    { VIRTIO_RING_F_##name, VIRTIO_TRANSPORT_FEATURE_##name }
+    FEATURE_ENTRY(INDIRECT_DESC),
+    FEATURE_ENTRY(EVENT_IDX),
+#undef FEATURE_ENTRY
+    { -1, -1 }
+};
+
 /*
  * The alignment to use between consumer and producer parts of vring.
  * x86 pagesize again. This is the default, used by transports like PCI
@@ -3912,6 +3935,103 @@ static VirtIODevice *virtio_device_find(const char *path)
     return NULL;
 }
 
+#define CONVERT_FEATURES(type, map)                \
+    ({                                           \
+        type *list = NULL;                         \
+        type *node;                                \
+        for (i = 0; map[i].virtio_bit != -1; i++) {\
+            bit = 1ULL << map[i].virtio_bit;       \
+            if ((bitmap & bit) == 0) {             \
+                continue;                          \
+            }                                      \
+            node = g_new0(type, 1);                \
+            node->value = map[i].qapi_virtio_enum; \
+            node->next = list;                     \
+            list = node;                           \
+            bitmap ^= bit;                         \
+        }                                          \
+        list;                                      \
+    })
+
+static VirtioDeviceFeatures *qmp_decode_features(const char *name,
+                                                 uint64_t bitmap)
+{
+    VirtioDeviceFeatures *features;
+    uint64_t bit;
+    int i;
+
+    features = g_new0(VirtioDeviceFeatures, 1);
+
+    /* transport features */
+    features->transport = CONVERT_FEATURES(VirtioTransportFeatureList, \
+                                           transport_map);
+
+    /* device features */
+    features->type = qapi_enum_parse(&VirtioType_lookup,
+                                     name, -1, NULL);
+    switch (features->type) {
+#ifdef CONFIG_VIRTIO_SERIAL
+    case VIRTIO_TYPE_VIRTIO_SERIAL:
+        features->u.virtio_serial.features =
+                          CONVERT_FEATURES(VirtioSerialFeatureList, serial_map);
+        break;
+#endif
+#ifdef CONFIG_VIRTIO_BLK
+    case VIRTIO_TYPE_VIRTIO_BLK:
+        features->u.virtio_blk.features =
+                                CONVERT_FEATURES(VirtioBlkFeatureList, blk_map);
+        break;
+#endif
+#ifdef CONFIG_VIRTIO_GPU
+    case VIRTIO_TYPE_VIRTIO_GPU:
+        features->u.virtio_gpu.features =
+                                CONVERT_FEATURES(VirtioGpuFeatureList, gpu_map);
+        break;
+#endif
+#ifdef CONFIG_VIRTIO_NET
+    case VIRTIO_TYPE_VIRTIO_NET:
+        features->u.virtio_net.features =
+                                CONVERT_FEATURES(VirtioNetFeatureList, net_map);
+        break;
+#endif
+#ifdef CONFIG_VIRTIO_SCSI
+    case VIRTIO_TYPE_VIRTIO_SCSI:
+        features->u.virtio_scsi.features =
+                              CONVERT_FEATURES(VirtioScsiFeatureList, scsi_map);
+        break;
+#endif
+#ifdef CONFIG_VIRTIO_BALLOON
+    case VIRTIO_TYPE_VIRTIO_BALLOON:
+        features->u.virtio_balloon.features =
+                        CONVERT_FEATURES(VirtioBalloonFeatureList, balloon_map);
+        break;
+#endif
+#ifdef CONFIG_VIRTIO_IOMMU
+    case VIRTIO_TYPE_VIRTIO_IOMMU:
+        features->u.virtio_iommu.features =
+                            CONVERT_FEATURES(VirtioIommuFeatureList, iommu_map);
+        break;
+#endif
+    /* No features */
+    case VIRTIO_TYPE_VIRTIO_9P:
+    case VIRTIO_TYPE_VIRTIO_INPUT:
+    case VIRTIO_TYPE_VHOST_USER_FS:
+    case VIRTIO_TYPE_VHOST_VSOCK:
+    case VIRTIO_TYPE_VIRTIO_CRYPTO:
+    case VIRTIO_TYPE_VIRTIO_PMEM:
+    case VIRTIO_TYPE_VIRTIO_RNG:
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    features->has_unknown_features = bitmap != 0;
+    if (features->has_unknown_features) {
+        features->unknown_features = bitmap;
+    }
+
+    return features;
+}
+
 VirtioStatus *qmp_x_debug_virtio_status(const char* path, Error **errp)
 {
     VirtIODevice *vdev;
@@ -3924,9 +4044,12 @@ VirtioStatus *qmp_x_debug_virtio_status(const char* path, Error **errp)
     }
 
     status = g_new0(VirtioStatus, 1);
-    status->guest_features = vdev->guest_features;
-    status->host_features = vdev->host_features;
-    status->backend_features = vdev->backend_features;
+    status->guest_features = qmp_decode_features(vdev->name,
+                                                 vdev->guest_features);
+    status->host_features = qmp_decode_features(vdev->name,
+                                                vdev->host_features);
+    status->backend_features = qmp_decode_features(vdev->name,
+                                                   vdev->backend_features);
     status->device_id = vdev->device_id;
 
     switch (vdev->device_endian) {
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index f7da326..b872dcf 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -163,6 +163,19 @@ struct VirtioDeviceClass {
     bool (*primary_unplug_pending)(void *opaque);
 };
 
+typedef struct {
+    int virtio_bit;
+    int qapi_virtio_enum;
+} qmp_virtio_feature_map_t;
+
+extern qmp_virtio_feature_map_t serial_map[];
+extern qmp_virtio_feature_map_t blk_map[];
+extern qmp_virtio_feature_map_t gpu_map[];
+extern qmp_virtio_feature_map_t net_map[];
+extern qmp_virtio_feature_map_t scsi_map[];
+extern qmp_virtio_feature_map_t balloon_map[];
+extern qmp_virtio_feature_map_t iommu_map[];
+
 void virtio_instance_init_common(Object *proxy_obj, void *data,
                                  size_t vdev_size, const char *vdev_name);
 
diff --git a/qapi/virtio.json b/qapi/virtio.json
index 4bd09c9..78873cd 100644
--- a/qapi/virtio.json
+++ b/qapi/virtio.json
@@ -83,6 +83,253 @@
 }
 
 ##
+# @VirtioTransportFeature:
+#
+# An enumeration of Virtio device transport features, including virtio-ring
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioTransportFeature',
+  'data': [ 'notify-on-empty', 'any-layout', 'version-1', 'iommu-platform',
+            'ring-packed', 'order-platform', 'sr-iov', 'indirect-desc',
+            'event-idx', 'bad-feature' ]
+}
+
+##
+# @VirtioSerialFeature:
+#
+# An enumeration of Virtio serial features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioSerialFeature',
+  'data': [ 'size', 'multiport', 'emerg-write' ]
+}
+
+##
+# @VirtioBlkFeature:
+#
+# An enumeration of Virtio block features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioBlkFeature',
+  'data': [ 'size-max', 'seg-max', 'geometry', 'ro', 'blk-size', 'topology',
+            'mq', 'discard', 'write-zeroes', 'barrier', 'scsi', 'flush',
+            'config-wce' ]
+}
+
+##
+# @VirtioGpuFeature:
+#
+# An enumeration of Virtio gpu features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioGpuFeature',
+  'data': [ 'virgl', 'edid', 'resource-uuid', 'resource-blob' ]
+}
+
+##
+# @VirtioNetFeature:
+#
+# An enumeration of Virtio net features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioNetFeature',
+  'data': [ 'csum', 'guest-csum', 'ctrl-guest-offloads', 'mtu', 'mac',
+            'guest-tso4', 'guest-tso6', 'guest-ecn', 'guest-ufo',
+            'host-tso4', 'host-tso6', 'host-ecn', 'host-ufo', 'mrg-rxbuf',
+            'status', 'ctrl-vq', 'ctrl-rx', 'ctrl-vlan', 'ctrl-rx-extra',
+            'guest-announce', 'mq', 'ctrl-mac-addr', 'standby',
+            'speed-duplex', 'gso', 'hash-report', 'rss', 'rsc-ext' ]
+}
+
+##
+# @VirtioScsiFeature:
+#
+# An enumeration of Virtio scsi features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioScsiFeature',
+  'data': [ 'inout', 'hotplug', 'change', 't10-pi' ]
+}
+
+##
+# @VirtioBalloonFeature:
+#
+# An enumeration of Virtio balloon features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioBalloonFeature',
+  'data': [ 'must-tell-host', 'stats-vq', 'deflate-on-oom', 'free-page-hint',
+            'page-poison', 'reporting' ]
+}
+
+##
+# @VirtioIommuFeature:
+#
+# An enumeration of Virtio iommu features
+#
+# Since: 6.1
+##
+
+{ 'enum': 'VirtioIommuFeature',
+  'data': [ 'input-range', 'domain-range', 'map-unmap', 'bypass', 'probe',
+            'mmio' ]
+}
+
+##
+# @VirtioDeviceFeaturesBase:
+#
+# The common fields that apply to all Virtio devices
+#
+# @type: virtio device type
+# @transport: the list of transport features of the virtio device
+# @unknown-features: virtio device features bitmap that have not been decoded
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesBase',
+  'data': {
+    'type': 'VirtioType',
+    'transport': [ 'VirtioTransportFeature' ],
+    '*unknown-features': 'uint64'
+  }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsSerial:
+#
+# The options that apply to Virtio serial device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsSerial',
+  'data': { 'features': [ 'VirtioSerialFeature' ] }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsBlk:
+#
+# The options that apply to Virtio block device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsBlk',
+  'data': { 'features': [ 'VirtioBlkFeature' ] }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsGpu:
+#
+# The options that apply to Virtio GPU device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsGpu',
+  'data': { 'features': [ 'VirtioGpuFeature' ] }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsNet:
+#
+# The options that apply to Virtio net device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsNet',
+  'data': { 'features': [ 'VirtioNetFeature' ] }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsScsi:
+#
+# The options that apply to Virtio SCSI device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsScsi',
+  'data': { 'features': [ 'VirtioScsiFeature' ] }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsBalloon:
+#
+# The options that apply to Virtio balloon device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsBalloon',
+  'data': { 'features': [ 'VirtioBalloonFeature' ] }
+}
+
+##
+# @VirtioDeviceFeaturesOptionsIommu:
+#
+# The options that apply to Virtio IOMMU device
+#
+# @features: List of the device features
+#
+# Since: 6.1
+##
+
+{ 'struct': 'VirtioDeviceFeaturesOptionsIommu',
+  'data': { 'features': [ 'VirtioIommuFeature' ] }
+}
+
+##
+# @VirtioDeviceFeatures:
+#
+# A union to define the list of features for a virtio device
+#
+# Since: 6.1
+##
+
+{ 'union': 'VirtioDeviceFeatures',
+  'base': 'VirtioDeviceFeaturesBase',
+  'discriminator': 'type',
+  'data': {
+    'virtio-serial': 'VirtioDeviceFeaturesOptionsSerial',
+    'virtio-blk': 'VirtioDeviceFeaturesOptionsBlk',
+    'virtio-gpu': 'VirtioDeviceFeaturesOptionsGpu',
+    'virtio-net': 'VirtioDeviceFeaturesOptionsNet',
+    'virtio-scsi': 'VirtioDeviceFeaturesOptionsScsi',
+    'virtio-balloon': 'VirtioDeviceFeaturesOptionsBalloon',
+    'virtio-iommu': 'VirtioDeviceFeaturesOptionsIommu'
+  }
+}
+
+##
 # @VirtioStatus:
 #
 # @device-id: VirtIODevice status
@@ -105,9 +352,9 @@
   'data': {
     'device-id': 'int',
     'device-endian': 'VirtioStatusEndianness',
-    'guest-features': 'uint64',
-    'host-features': 'uint64',
-    'backend-features': 'uint64',
+    'guest-features': 'VirtioDeviceFeatures',
+    'host-features': 'VirtioDeviceFeatures',
+    'backend-features': 'VirtioDeviceFeatures',
     'num-vqs': 'uint16'
   }
 }
@@ -127,18 +374,31 @@
 #
 # -> { "execute": "x-debug-virtio-status",
 #      "arguments": {
-#          "path": "/machine/peripheral-anon/device[3]/virtio-backend"
+#          "path": "/machine/peripheral-anon/device[1]/virtio-backend"
 #      }
 #   }
 # <- { "return": {
-#          "backend-features": 0,
-#          "guest-features": 5111807911,
-#          "num-vqs": 3,
-#          "host-features": 6337593319,
 #          "device-endian": "little",
-#          "device-id": 1
+#          "device-id": 3,
+#          "backend-features": {
+#              "transport": [],
+#              "type": "virtio-serial",
+#              "features": []
+#          },
+#          "num-vqs": 64,
+#          "guest-features": {
+#              "transport": [ "event-idx", "indirect-desc", "version-1" ],
+#              "type": "virtio-serial",
+#              "features": [ "multiport" ]
+#          },
+#          "host-features": {
+#              "transport": [ "event-idx", "indirect-desc", "bad-feature",
+#                             "version-1", "any-layout", "notify-on-empty" ],
+#              "type": "virtio-serial",
+#              "features": [ "emerg-write", "multiport" ]
+#          }
 #      }
-#    }
+#  }
 #
 ##
 
-- 
1.8.3.1