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Re: [Qemu-block] [Qemu-devel] [PATCH v4 1/2] virtio: introduce `query-vi
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH v4 1/2] virtio: introduce `query-virtio' QMP command |
Date: |
Tue, 3 Oct 2017 09:02:27 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 |
On 10/03/2017 07:47 AM, Jan Dakinevich wrote:
> The command is intended for gathering virtio information such as status,
> feature bits, negotiation status. It is convenient and useful for debug
> purpose.
>
> The commands returns generic virtio information for virtio such as
> common feature names and status bits names and information for all
> attached to current machine devices.
>
> To retrieve names of device-specific features `get_feature_name'
> callback in VirtioDeviceClass also was introduced.
>
> Cc: Denis V. Lunev <address@hidden>
> Signed-off-by: Jan Dakinevich <address@hidden>
> ---
> hw/block/virtio-blk.c | 21 +++++++++
> hw/char/virtio-serial-bus.c | 15 +++++++
> hw/display/virtio-gpu.c | 13 ++++++
> hw/net/virtio-net.c | 35 +++++++++++++++
> hw/scsi/virtio-scsi.c | 16 +++++++
> hw/virtio/Makefile.objs | 2 +
> hw/virtio/virtio-balloon.c | 15 +++++++
> hw/virtio/virtio-stub.c | 9 ++++
> hw/virtio/virtio.c | 101
> ++++++++++++++++++++++++++++++++++++++++++++
> include/hw/virtio/virtio.h | 2 +
> qapi-schema.json | 1 +
> qapi/virtio.json | 94 +++++++++++++++++++++++++++++++++++++++++
> 12 files changed, 324 insertions(+)
> create mode 100644 hw/virtio/virtio-stub.c
> create mode 100644 qapi/virtio.json
This creates a new .json file, but does not touch MAINTAINERS. Our idea
in splitting the .json files was to make it easier for each sub-file
that needs a specific maintainer in addition to the overall *.json line
for QAPI maintainers, so this may deserve a MAINTAINERS entry.
> +++ b/qapi/virtio.json
> @@ -0,0 +1,94 @@
> +# -*- Mode: Python -*-
> +#
> +
> +##
> +# = Virtio devices
> +##
> +
> +{ 'include': 'common.json' }
> +
> +##
> +# @VirtioInfoBit:
> +#
> +# Named virtio bit
> +#
> +# @bit: bit number
> +#
> +# @name: bit name
> +#
> +# Since: 2.11.0
> +#
> +##
> +{
> + 'struct': 'VirtioInfoBit',
> + 'data': {
> + 'bit': 'uint64',
Why is this a 64-bit value? Are the values 0-63, or are they 1, 2, 4, 8,
...? The documentation on 'bit number' is rather sparse.
> + 'name': 'str'
Wouldn't an enum type be better than an open-ended string?
> + }
> +}
> +
> +##
> +# @VirtioInfoDevice:
> +#
> +# Information about specific virtio device
> +#
> +# @qom_path: QOM path of the device
Please make this 'qom-path' - new interfaces should prefer '-' over '_'.
> +#
> +# @feature-names: names of device-specific features
> +#
> +# @host-features: bitmask of features, provided by devices
> +#
> +# @guest-features: bitmask of features, acknowledged by guest
> +#
> +# @status: virtio device status bitmask
> +#
> +# Since: 2.11.0
> +#
> +##
> +{
> + 'struct': 'VirtioInfoDevice',
> + 'data': {
> + 'qom_path': 'str',
> + 'feature-names': ['VirtioInfoBit'],
> + 'host-features': 'uint64',
> + 'guest-features': 'uint64',
> + 'status': 'uint64'
I'm wondering if this is the best representation (where the caller has
to parse the integer and then lookup in feature-names what each bit of
the integer represents). But I'm not sure I have anything better off
the top of my head.
> + }
> +}
> +
> +##
> +# @VirtioInfo:
> +#
> +# Information about virtio devices
> +#
> +# @feature-names: names of common virtio features
> +#
> +# @status-names: names of bits which represents virtio device status
> +#
> +# @devices: list of per-device virtio information
> +#
> +# Since: 2.11.0
> +#
> +##
> +{
> + 'struct': 'VirtioInfo',
> + 'data': {
> + 'feature-names': ['VirtioInfoBit'],
Why is feature-names listed at two different nestings of the return value?
> + 'status-names': ['VirtioInfoBit'],
> + 'devices': ['VirtioInfoDevice']
> + }
> +}
> +
> +
> +##
> +# @query-virtio:
> +#
> +# Returns generic and per-device virtio information
> +#
> +# Since: 2.11.0
> +#
> +##
> +{
> + 'command': 'query-virtio',
> + 'returns': 'VirtioInfo'
> +}
>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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