This series introduces new QMP/HMP commands to dump the status
of a a virtio device at different levels.
1. Main command
HMP Only:
x-debug-virtio [subcommand]
Example:
List all sub-commands:
(qemu) x-debug-virtio
x-debug-virtio query -- List all available virtio devices
x-debug-virtio status path -- Display status of a given virtio device
x-debug-virtio queue-status path queue -- Display status of a given virtio queue
x-debug-virtio queue-element path queue [index] -- Display element of a given virtio queue
2. List available virtio devices in the machine
HMP Form:
x-debug-virtio query
Example:
(qemu) x-debug-virtio query
/machine/peripheral-anon/device[3]/virtio-backend [virtio-net]
/machine/peripheral-anon/device[1]/virtio-backend [virtio-serial]
/machine/peripheral-anon/device[0]/virtio-backend [virtio-blk]
QMP Form:
{ 'command': 'x-debug-query-virtio', 'returns': ['VirtioInfo'] }
Example:
-> { "execute": "x-debug-query-virtio" }
<- { "return": [
{
"path": "/machine/peripheral-anon/device[3]/virtio-backend",
"type": "virtio-net"
},
{
"path": "/machine/peripheral-anon/device[1]/virtio-backend",
"type": "virtio-serial"
},
{
"path": "/machine/peripheral-anon/device[0]/virtio-backend",
"type": "virtio-blk"
}
]
}
3. Display status of a given virtio device
HMP Form:
x-debug-virtio status <path>
Example:
(qemu) x-debug-virtio status /machine/peripheral-anon/device[3]/virtio-backend
/machine/peripheral-anon/device[3]/virtio-backend:
Device Id: 1
Guest features: event-idx, indirect-desc, version-1
ctrl-mac-addr, guest-announce, ctrl-vlan, ctrl-rx, ctrl-vq, status, mrg-rxbuf, host-ufo, host-ecn, host-tso6, host-tso4, guest-ufo, guest-ecn, guest-tso6, guest-tso4, mac, ctrl-guest-offloads, guest-csum, csum
Host features: event-idx, indirect-desc, bad-feature, version-1, any-layout, notify-on-empty
gso, ctrl-mac-addr, guest-announce, ctrl-rx-extra, ctrl-vlan, ctrl-rx, ctrl-vq, status, mrg-rxbuf, host-ufo, host-ecn, host-tso6, host-tso4, guest-ufo, guest-ecn, guest-tso6, guest-tso4, mac, ctrl-guest-offloads, guest-csum, csum
Backend features:
Endianness: little
VirtQueues: 3
QMP Form:
{ 'command': 'x-debug-virtio-status',
'data': { 'path': 'str' },
'returns': 'VirtioStatus'
}
Example:
-> { "execute": "x-debug-virtio-status",
"arguments": {
"path": "/machine/peripheral-anon/device[3]/virtio-backend"
}
}
<- { "return": {
"device-endian": "little",
"device-id": 1,
"backend-features": {
"device": {
"type": "virtio-net",
"data": []
},
"unknown": 0,
"transport": []
},
"num-vqs": 3,
"guest-features": {
"device": {
"type": "virtio-net",
"data": [ "ctrl-mac-addr", "guest-announce", "ctrl-vlan", "ctrl-rx",
"ctrl-vq", "status", "mrg-rxbuf", "host-ufo", "host-ecn",
"host-tso6", "host-tso4", "guest-ufo", "guest-ecn",
"guest-tso6", "guest-tso4", "mac", "ctrl-guest-offloads",
"guest-csum", "csum" ]
},
"unknown": 0,
"transport": [ "event-idx", "indirect-desc", "version-1" ]
},
"host-features": {
"device": {
"type": "virtio-net",
"data": [ "gso", "ctrl-mac-addr", "guest-announce", "ctrl-rx-extra",
"ctrl-vlan", "ctrl-rx", "ctrl-vq", "status", "mrg-rxbuf",
"host-ufo", "host-ecn", "host-tso6", "host-tso4",
"guest-ufo", "guest-ecn", "guest-tso6", "guest-tso4",
"mac", "ctrl-guest-offloads", "guest-csum", "csum" ]
},
"unknown": 0,
"transport": [ "event-idx", "indirect-desc", "bad-feature",
"version-1", "any-layout", "notify-on-empty" ]
}
}
}
4. Display status of a given virtio queue
HMP Form:
x-debug-virtio queue-status <path> <queue>
Example:
(qemu) x-debug-virtio queue-status /machine/peripheral-anon/device[3]/virtio-backend 0
/machine/peripheral-anon/device[3]/virtio-backend:
index: 0
inuse: 0
last_avail_idx: 61
shadow_avail_idx: 292
signalled_used: 61
signalled_used_valid: 1
VRing:
num: 256
num_default: 256
align: 4096
desc: 0x000000006c352000
avail: 0x000000006c353000
used: 0x000000006c353240
QMP Form:
{ 'command': 'x-debug-virtio-queue-status',
'data': { 'path': 'str', 'queue': 'uint16' },
'returns': 'VirtQueueStatus'
}
Example:
-> { "execute": "x-debug-virtio-queue-status",
"arguments": {
"path": "/machine/peripheral-anon/device[3]/virtio-backend",
"queue": 0
}
}
<- { "return": {
"signalled_used": 373,
"inuse": 0,
"vring_desc": 864411648,
"vring_num_default": 256,
"signalled_used_valid": 1,
"vring_avail": 864415744,
"last_avail_idx": 373,
"queue_index": 0,
"vring_used": 864416320,
"shadow_avail_idx": 619,
"used_idx": 373,
"vring_num": 256,
"vring_align": 4096
}
}
5. Display element of a given virtio queue
HMP Form:
x-debug-virtio queue-element <path> <queue> [index]
Example:
Dump the information of the head element of the first queue of
the first virtio device::
(qemu) x-debug-virtio queue-element/machine/peripheral-anon/device[3]/virtio-backend 0
index: 67
ndescs: 1
descs: addr 0x6fe69800 len 1536 (write)
(qemu) xp/128bx 0x6fe69800
000000006fe69800: 0x02 0x00 0x00 0x00 0x00 0x00 0x00 0x00
000000006fe69808: 0x00 0x00 0x01 0x00 0x52 0x54 0x00 0x12
000000006fe69810: 0x34 0x56 0x52 0x54 0x00 0x09 0x51 0xde
000000006fe69818: 0x08 0x00 0x45 0x00 0x00 0x4c 0x8f 0x32
device[3] is a virtio-net device and we can see in the element buffer the
MAC address of the card::
[root@localhost ~]# ip link show ens4
2: ens4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP m0
link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff
and the MAC address of the gateway::
[root@localhost ~]# arp -a
_gateway (192.168.122.1) at 52:54:00:09:51:de [ether] on ens4
QMP Form:
{ 'command': 'x-debug-virtio-queue-element',
'data': { 'path': 'str', 'queue': 'uint16', '*index': 'uint16' },
'returns': 'VirtioQueueElement'
}
Example:
-> { "execute": "x-debug-virtio-queue-element",
"arguments": {
"path": "/machine/peripheral-anon/device[3]/virtio-backend",
"queue": 0
}
}
-> { "return": {
"index": 109,
"ndescs": 1,
"descs": [
{ "flags": [ "write" ], "len": 1536, "addr": 853145600 }
]
}
}
v4: re-send series as v3 didn't reach qemu-devel
v3: use qapi_free_VirtioInfoList() on the head of the list, not on the tail
prefix the commands with x-debug-
v2: introduce VirtioType enum
use an enum for the endianness
change field names to stick to naming conventions (s/_/-/)
add a patch to decode feature bits
don't check if the queue is empty to allow to displa old elements
use enum for desc flags
manage indirect desc
decode device features in the HMP command
Laurent Vivier (6):
qmp: add QMP command x-debug-query-virtio
qmp: add QMP command x-debug-virtio-status
qmp: decode feature bits in virtio-status
qmp: add QMP command x-debug-virtio-queue-status
qmp: add QMP command x-debug-virtio-queue-element
hmp: add x-debug-virtio commands
Makefile | 2 +-
Makefile.target | 7 +-
docs/system/monitor.rst | 2 +
hmp-commands-virtio.hx | 160 +++++++++++
hmp-commands.hx | 10 +
hw/block/virtio-blk.c | 23 ++
hw/char/virtio-serial-bus.c | 11 +
hw/display/virtio-gpu-base.c | 10 +
hw/net/virtio-net.c | 35 +++
hw/scsi/virtio-scsi.c | 12 +
hw/virtio/Makefile.objs | 2 +
hw/virtio/virtio-balloon.c | 13 +
hw/virtio/virtio-iommu.c | 14 +
hw/virtio/virtio-stub.c | 34 +++
hw/virtio/virtio.c | 542 +++++++++++++++++++++++++++++++++++
include/hw/virtio/virtio.h | 14 +
include/monitor/hmp.h | 4 +
monitor/misc.c | 17 ++
qapi/Makefile.objs | 2 +-
qapi/qapi-schema.json | 1 +
qapi/virtio.json | 502 ++++++++++++++++++++++++++++++++
tests/qtest/qmp-cmd-test.c | 1 +
22 files changed, 1414 insertions(+), 4 deletions(-)
create mode 100644 hmp-commands-virtio.hx
create mode 100644 hw/virtio/virtio-stub.c
create mode 100644 qapi/virtio.json
--
2.26.2