Re: [Qemu-devel] [PATCH v2] virtio: introduce `info virtio' hmp command

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Jan Dakinevich (jan.dakinevich@virtuozzo.com) wrote:
> The command is intended for exposing device specific virtio feature bits
> and their negotiation status. It is convenient and useful for debug
> purpose.
> 
> Names of features are taken from a devices via get_feature_name() within
> VirtioDeviceClass. If certain device doesn't implement it, the command
> will print only hexadecimal value of feature mask.
> 
> Cc: Denis V. Lunev <den@virtuozzo.com>
> Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com>
> ---
> v2:
> * Moved hmp_info_virtio and stuff to hmp.c to avoid build error
> * Added printing of device status
> * Listed common virtio features
> 
> v1: http://lists.nongnu.org/archive/html/qemu-devel/2017-09/msg07247.html
> ---
>  hmp-commands-info.hx        |  14 +++++
>  hmp.c                       | 148 ++++++++++++++++++++++++++++++++++++++++++++
>  hmp.h                       |   1 +
>  hw/block/virtio-blk.c       |  20 ++++++
>  hw/char/virtio-serial-bus.c |  15 +++++
>  hw/display/virtio-gpu.c     |  12 ++++
>  hw/net/virtio-net.c         |  34 ++++++++++
>  hw/scsi/virtio-scsi.c       |  15 +++++
>  hw/virtio/virtio-balloon.c  |  15 +++++
>  hw/virtio/virtio-bus.c      |   1 +
>  include/hw/virtio/virtio.h  |   2 +
>  monitor.c                   |   1 +
>  12 files changed, 278 insertions(+)
> 
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index 4f1ece9..2550027 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -868,6 +868,20 @@ ETEXI
>      },
>  
>  STEXI
> +@item info virtio
> +@findex virtio
> +Display guest and host fetures for all virtio devices.
> +ETEXI
> +
> +    {
> +        .name       = "virtio",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "show virtio info",
> +        .cmd        = hmp_info_virtio,
> +    },
> +
> +STEXI
>  @end table
>  ETEXI
>  
> diff --git a/hmp.c b/hmp.c
> index ace729d..009d808 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -43,6 +43,7 @@
>  #include "hw/intc/intc.h"
>  #include "migration/snapshot.h"
>  #include "migration/misc.h"
> +#include "hw/virtio/virtio.h"
>  
>  #ifdef CONFIG_SPICE
>  #include <spice/enums.h>
> @@ -2894,3 +2895,150 @@ void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict)
>      }
>      hmp_handle_error(mon, &err);
>  }
> +
> +#define HMP_INFO_VIRTIO_INDENT 2
> +#define HMP_INFO_VIRTIO_FIELD 32
> +
> +static void hmp_info_virtio_print_status(Monitor *mon, VirtIODevice *vdev)
> +{
> +    uint8_t status[] = {
> +        VIRTIO_CONFIG_S_ACKNOWLEDGE,
> +        VIRTIO_CONFIG_S_DRIVER,
> +        VIRTIO_CONFIG_S_DRIVER_OK,
> +        VIRTIO_CONFIG_S_FEATURES_OK,
> +        VIRTIO_CONFIG_S_NEEDS_RESET,
> +        VIRTIO_CONFIG_S_FAILED,
> +    };
> +    const char *names[] = {
> +        "acknowledge",
> +        "driver",
> +        "driver_ok",
> +        "features_ok",
> +        "needs_reset"
> +        "failed",
> +    };
> +    const char *comma = "";
> +    int idx;
> +
> +    monitor_printf(mon, "%*sstatus:           0x%02"PRIx8" ",
> +                   HMP_INFO_VIRTIO_INDENT, "", vdev->status);
> +
> +    for (idx = 0; idx < ARRAY_SIZE(status); idx++) {
> +        if (!(vdev->status & status[idx])) {
> +            continue;
> +        }
> +        monitor_printf(mon, "%s%s", comma, names[idx]);
> +        if (names[idx]) {
> +            comma = ",";
> +        }
> +    }
> +    monitor_printf(mon, "\n");
> +}
> +
> +static void hmp_info_virtio_print_common_features(Monitor *mon,
> +                                                  VirtIODevice *vdev)
> +{
> +    uint64_t features[] = {
> +        VIRTIO_RING_F_INDIRECT_DESC,
> +        VIRTIO_RING_F_EVENT_IDX,
> +        VIRTIO_F_NOTIFY_ON_EMPTY,
> +        VIRTIO_F_ANY_LAYOUT,
> +        VIRTIO_F_IOMMU_PLATFORM,
> +        VIRTIO_F_VERSION_1,
> +    };
> +    const char *names[] = {
> +        "indirect_desc",
> +        "event_idx",
> +        "notify_on_empty",
> +        "any_layout",
> +        "iommu_platform",
> +        "version_1",
> +    };
> +    int idx;
> +
> +    monitor_printf(mon, "%*scommon features:\n", HMP_INFO_VIRTIO_INDENT, "");
> +
> +    for (idx = 0; idx < ARRAY_SIZE(features); idx++) {
> +        const char *ack = vdev->guest_features & features[idx] ? "acked" : "";
> +
> +        if (!(vdev->host_features & features[idx])) {
> +            continue;
> +        }
> +        monitor_printf(mon, "%*s%*s%*s\n", HMP_INFO_VIRTIO_INDENT, "",
> +                       HMP_INFO_VIRTIO_FIELD, names[idx],
> +                       HMP_INFO_VIRTIO_FIELD, ack);
> +    }
> +}
> +
> +static void hmp_info_virtio_print_specific_features(Monitor *mon,
> +                                                    VirtIODevice *vdev)
> +{
> +    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
> +    int idx;
> +
> +    if (!vdc->get_feature_name) {
> +        return;
> +    }
> +
> +    monitor_printf(mon, "%*sspecific features:\n", HMP_INFO_VIRTIO_INDENT, "");
> +
> +    for (idx = 0; idx < 64; idx++) {
> +        const char *name = vdc->get_feature_name(vdev, idx);
> +        const char *ack = vdev->guest_features & (1 << idx) ? "acked" : "";
> +
> +        if (!name) {
> +            continue;
> +        }
> +        if (!(vdev->host_features & (1 << idx))) {

Does that need to be 1ull ?

> +            continue;
> +        }
> +        monitor_printf(mon, "%*s%*s%*s\n", HMP_INFO_VIRTIO_INDENT, "",
> +                       HMP_INFO_VIRTIO_FIELD, name, HMP_INFO_VIRTIO_FIELD, ack);
> +    }
> +}
> +
> +static void hmp_info_virtio_print(Monitor *mon, VirtIODevice *vdev)
> +{
> +    char *path = qdev_get_dev_path(DEVICE(vdev));
> +
> +    monitor_printf(mon, "%s at %s\n", object_get_typename(OBJECT(vdev)), path);
> +    g_free(path);
> +
> +    hmp_info_virtio_print_status(mon, vdev);
> +
> +    monitor_printf(mon, "%*shost features:    0x%016"PRIx64"\n",
> +                   HMP_INFO_VIRTIO_INDENT, "", vdev->host_features);
> +    monitor_printf(mon, "%*sguest features:   0x%016"PRIx64"\n",
> +                   HMP_INFO_VIRTIO_INDENT, "", vdev->guest_features);
> +
> +    hmp_info_virtio_print_common_features(mon, vdev);
> +    hmp_info_virtio_print_specific_features(mon, vdev);
> +}
> +
> +static void hmp_info_virtio_recursive(Monitor *mon, BusState *bus)
> +{
> +    BusChild *kid;
> +
> +    QTAILQ_FOREACH(kid, &bus->children, sibling) {
> +        DeviceState *dev = kid->child;
> +        BusState *child;
> +
> +        if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_DEVICE)) {
> +            hmp_info_virtio_print(mon, VIRTIO_DEVICE(dev));
> +        }
> +        QLIST_FOREACH(child, &dev->child_bus, sibling) {
> +            hmp_info_virtio_recursive(mon, child);
> +        }
> +    }
> +}
> +
> +void hmp_info_virtio(Monitor *mon, const QDict *qdict)
> +{
> +    BusState *bus = sysbus_get_default();
> +
> +    if (!bus) {
> +        return;
> +    }
> +
> +    hmp_info_virtio_recursive(mon, bus);
> +}
> diff --git a/hmp.h b/hmp.h
> index 3605003..3e8f30a 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -146,5 +146,6 @@ void hmp_info_ramblock(Monitor *mon, const QDict *qdict);
>  void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict);
>  void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict);
>  void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict);
> +void hmp_info_virtio(Monitor *mon, const QDict *qdict);
>  
>  #endif
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 05d1440..5856640 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -1017,6 +1017,25 @@ static Property virtio_blk_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> +static const char *virtio_blk_get_feature_name(VirtIODevice *vdev, int feature)

Please make the 'feature' parameter to all these unsigned for safety.

> +{
> +    static const char *names[] = {
> +        [VIRTIO_BLK_F_BARRIER] = "barrier",
> +        [VIRTIO_BLK_F_SIZE_MAX] = "size_max",
> +        [VIRTIO_BLK_F_SEG_MAX] = "seg_max",
> +        [VIRTIO_BLK_F_RO] = "ro",
> +        [VIRTIO_BLK_F_BLK_SIZE] = "blk_size",
> +        [VIRTIO_BLK_F_SCSI] = "scsi",
> +        [VIRTIO_BLK_F_TOPOLOGY] = "topology",
> +        [VIRTIO_BLK_F_FLUSH] = "flush",
> +        [VIRTIO_BLK_F_MQ] = "mq",
> +    };
> +    if (feature >= ARRAY_SIZE(names)) {
> +        return NULL;

Is it easier to make this return "(unknown)" rather than having
to check it at the point of call?
(Actually it's a shame you need to do this - the contrib/libvhost-user
code had a similar name expansion thing)

> +    }
> +    return names[feature];
> +}
> +
>  static void virtio_blk_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -1030,6 +1049,7 @@ static void virtio_blk_class_init(ObjectClass *klass, void *data)
>      vdc->get_config = virtio_blk_update_config;
>      vdc->set_config = virtio_blk_set_config;
>      vdc->get_features = virtio_blk_get_features;
> +    vdc->get_feature_name = virtio_blk_get_feature_name;
>      vdc->set_status = virtio_blk_set_status;
>      vdc->reset = virtio_blk_reset;
>      vdc->save = virtio_blk_save_device;
> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> index 9470bd7..a6ccb6a 100644
> --- a/hw/char/virtio-serial-bus.c
> +++ b/hw/char/virtio-serial-bus.c
> @@ -1156,6 +1156,20 @@ static Property virtio_serial_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> +static const char *virtio_serial_get_feature_name(VirtIODevice *vdev,
> +                                                  int feature)
> +{
> +    static const char *names[] = {
> +        [VIRTIO_CONSOLE_F_SIZE] = "size",
> +        [VIRTIO_CONSOLE_F_MULTIPORT] = "multiport",
> +        [VIRTIO_CONSOLE_F_EMERG_WRITE] = "emerg_write",
> +    };
> +    if (feature >= ARRAY_SIZE(names)) {
> +        return NULL;
> +    }
> +    return names[feature];
> +}
> +
>  static void virtio_serial_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -1170,6 +1184,7 @@ static void virtio_serial_class_init(ObjectClass *klass, void *data)
>      vdc->realize = virtio_serial_device_realize;
>      vdc->unrealize = virtio_serial_device_unrealize;
>      vdc->get_features = get_features;
> +    vdc->get_feature_name = virtio_serial_get_feature_name;
>      vdc->get_config = get_config;
>      vdc->set_config = set_config;
>      vdc->set_status = set_status;
> diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
> index 3a8f1e1..860d2b3 100644
> --- a/hw/display/virtio-gpu.c
> +++ b/hw/display/virtio-gpu.c
> @@ -1307,6 +1307,17 @@ static Property virtio_gpu_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> +static const char *virtio_gpu_get_feature_name(VirtIODevice *vdev, int feature)
> +{
> +    static const char *names[] = {
> +        [VIRTIO_GPU_F_VIRGL] = "virgl",
> +    };
> +    if (feature >= ARRAY_SIZE(names)) {
> +        return NULL;
> +    }
> +    return names[feature];
> +}
> +
>  static void virtio_gpu_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -1317,6 +1328,7 @@ static void virtio_gpu_class_init(ObjectClass *klass, void *data)
>      vdc->get_config = virtio_gpu_get_config;
>      vdc->set_config = virtio_gpu_set_config;
>      vdc->get_features = virtio_gpu_get_features;
> +    vdc->get_feature_name = virtio_gpu_get_feature_name;
>      vdc->set_features = virtio_gpu_set_features;
>  
>      vdc->reset = virtio_gpu_reset;
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 148071a..e1d5d5d 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -2154,6 +2154,39 @@ static Property virtio_net_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> +static const char *virtio_net_get_feature_name(VirtIODevice *vdev, int feature)
> +{
> +    static const char *names[] = {
> +        [VIRTIO_NET_F_CSUM] = "csum",
> +        [VIRTIO_NET_F_GUEST_CSUM] = "guest_csum",
> +        [VIRTIO_NET_F_CTRL_GUEST_OFFLOADS] = "ctrl_guest_offloads",
> +        [VIRTIO_NET_F_MTU] = "mtu",
> +        [VIRTIO_NET_F_MAC] = "mac",
> +        [VIRTIO_NET_F_GSO] = "gso",
> +        [VIRTIO_NET_F_GUEST_TSO4] = "guest_tso4",
> +        [VIRTIO_NET_F_GUEST_TSO6] = "guest_tso6",
> +        [VIRTIO_NET_F_GUEST_ECN] = "guest_ecn",
> +        [VIRTIO_NET_F_GUEST_UFO] = "guest_ufo",
> +        [VIRTIO_NET_F_HOST_TSO4] = "host_tso4",
> +        [VIRTIO_NET_F_HOST_TSO6] = "host_tso6",
> +        [VIRTIO_NET_F_HOST_ECN] = "host_ecn",
> +        [VIRTIO_NET_F_HOST_UFO] = "host_ufo",
> +        [VIRTIO_NET_F_MRG_RXBUF] = "mrg_rxbuf",
> +        [VIRTIO_NET_F_STATUS] = "status",
> +        [VIRTIO_NET_F_CTRL_VQ] = "ctrl_vq",
> +        [VIRTIO_NET_F_CTRL_RX] = "ctrl_rx",
> +        [VIRTIO_NET_F_CTRL_VLAN] = "ctrl_vlan",
> +        [VIRTIO_NET_F_CTRL_RX_EXTRA] = "ctrl_rx_extra",
> +        [VIRTIO_NET_F_GUEST_ANNOUNCE] = "guest_announce",
> +        [VIRTIO_NET_F_MQ] = "mq",
> +        [VIRTIO_NET_F_CTRL_MAC_ADDR] = "ctrl_mac_addr",
> +    };
> +    if (feature >= ARRAY_SIZE(names)) {
> +        return NULL;
> +    }
> +    return names[feature];
> +}
> +
>  static void virtio_net_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -2169,6 +2202,7 @@ static void virtio_net_class_init(ObjectClass *klass, void *data)
>      vdc->get_features = virtio_net_get_features;
>      vdc->set_features = virtio_net_set_features;
>      vdc->bad_features = virtio_net_bad_features;
> +    vdc->get_feature_name = virtio_net_get_feature_name;
>      vdc->reset = virtio_net_reset;
>      vdc->set_status = virtio_net_set_status;
>      vdc->guest_notifier_mask = virtio_net_guest_notifier_mask;
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 3aa9971..4365c0a 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -942,6 +942,20 @@ static const VMStateDescription vmstate_virtio_scsi = {
>      },
>  };
>  
> +static const char *virtio_scsi_get_feature_name(VirtIODevice *vdev, int feature)
> +{
> +    static const char *names[] = {
> +        [VIRTIO_SCSI_F_INOUT] = "inout",
> +        [VIRTIO_SCSI_F_HOTPLUG] = "hotplug",
> +        [VIRTIO_SCSI_F_CHANGE] = "change",
> +        [VIRTIO_SCSI_F_T10_PI] = "t10_pi",
> +    };
> +    if (feature >= ARRAY_SIZE(names)) {
> +        return NULL;
> +    }
> +    return names[feature];
> +}
> +
>  static void virtio_scsi_common_class_init(ObjectClass *klass, void *data)
>  {
>      VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
> @@ -964,6 +978,7 @@ static void virtio_scsi_class_init(ObjectClass *klass, void *data)
>      vdc->unrealize = virtio_scsi_device_unrealize;
>      vdc->set_config = virtio_scsi_set_config;
>      vdc->get_features = virtio_scsi_get_features;
> +    vdc->get_feature_name = virtio_scsi_get_feature_name;
>      vdc->reset = virtio_scsi_reset;
>      vdc->start_ioeventfd = virtio_scsi_dataplane_start;
>      vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 37cde38..04f4e66 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -509,6 +509,20 @@ static Property virtio_balloon_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> +static const char *virtio_balloon_get_feature_name(VirtIODevice *vdev,
> +                                                   int feature)
> +{
> +    static const char *names[] = {
> +        [VIRTIO_BALLOON_F_MUST_TELL_HOST] = "must_tell_host",
> +        [VIRTIO_BALLOON_F_STATS_VQ] = "stats_vq",
> +        [VIRTIO_BALLOON_F_DEFLATE_ON_OOM] = "deflate_on_oom",
> +    };
> +    if (feature >= ARRAY_SIZE(names)) {
> +        return NULL;
> +    }
> +    return names[feature];
> +}
> +
>  static void virtio_balloon_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -523,6 +537,7 @@ static void virtio_balloon_class_init(ObjectClass *klass, void *data)
>      vdc->get_config = virtio_balloon_get_config;
>      vdc->set_config = virtio_balloon_set_config;
>      vdc->get_features = virtio_balloon_get_features;
> +    vdc->get_feature_name = virtio_balloon_get_feature_name;
>      vdc->set_status = virtio_balloon_set_status;
>      vdc->vmsd = &vmstate_virtio_balloon_device;
>  }
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index 3042232..e9ae54f 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -30,6 +30,7 @@
>  #include "hw/virtio/virtio-bus.h"
>  #include "hw/virtio/virtio.h"
>  #include "exec/address-spaces.h"
> +#include "monitor/monitor.h"
>  
>  /* #define DEBUG_VIRTIO_BUS */
>  
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 80c45c3..9b324f6 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -141,6 +141,8 @@ typedef struct VirtioDeviceClass {
>      void (*save)(VirtIODevice *vdev, QEMUFile *f);
>      int (*load)(VirtIODevice *vdev, QEMUFile *f, int version_id);
>      const VMStateDescription *vmsd;
> +    /* Get the name of device specific feature */
> +    const char *(*get_feature_name)(VirtIODevice *vdev, int feature);
>  } VirtioDeviceClass;
>  
>  void virtio_instance_init_common(Object *proxy_obj, void *data,
> diff --git a/monitor.c b/monitor.c
> index f4856b9..779f168 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -78,6 +78,7 @@
>  #include "sysemu/cpus.h"
>  #include "qemu/cutils.h"
>  #include "qapi/qmp/dispatch.h"
> +#include "hw/virtio/virtio-bus.h"
>  
>  #if defined(TARGET_S390X)
>  #include "hw/s390x/storage-keys.h"
> -- 
> 2.1.4

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK