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Re: [Qemu-devel] [QAPI+QGA 3/3] QEMU Guest Agent (virtagent) v7
From: |
Zhi Yong Wu |
Subject: |
Re: [Qemu-devel] [QAPI+QGA 3/3] QEMU Guest Agent (virtagent) v7 |
Date: |
Fri, 15 Jul 2011 09:15:18 +0800 |
On Fri, Jul 15, 2011 at 4:00 AM, Michael Roth <address@hidden> wrote:
> This is Set 3/3 of the QAPI+QGA patchsets.
>
> These patches apply on top of qapi-backport-set2-v6, and can also be obtained
> from:
> git://repo.or.cz/qemu/mdroth.git qapi-backport-set3-v7
>
> (Set1+2 are a backport of some of the QAPI-related work from Anthony's
> glib tree. The main goal is to get the basic code generation infrastructure in
> place so that it can be used by the guest agent to implement a QMP-like guest
> interface, and so that future work regarding the QMP conversion to QAPI can be
> decoupled from the infrastructure bits. Set3 is the Qemu Guest Agent
> (virtagent), rebased on the new code QAPI code generation infrastructure. This
> is the first user of QAPI, QMP will follow.)
> ___
>
> CHANGES SINCE V6:
> - Made "/dev/virtio-ports/org.qemu.guest_agent.0" default device path for
> agent
> - Consolidated uneeded fcntl() calls into qemu_open()
> - JSON/QMP parse errors now propagated to client
> - Replaced non-assertion uses of g_error() with exit()
> - Added guest-file-flush
> - Removed limit on max read size for guest-file-read
> - 'count' parameters to guest-file-read/guest-file-write are now optional
> (default to 4KB and size of provided buffer, base64-decoded, respectively)
> - Removed redundant 'file_' and 'shutdown_' prefixes from
> guest-file-*/guest-shutdown commands, switched to "-" in place of "_" in
> parameter names, renamed guest-file-read's "buf" param to "buf-b64" and
> guest-file-write's "data_b64" param to "buf-b64" for consistency.
> - guest-fsfreeze-freeze now returns error objects on error rather as part of
> it's integer return values, and on error will unfreeze previously frozen
> filesystems.
> - GUEST_FSFREEZE_STATUS_INPROGRESS removed, GUEST_FSFREEZE_STATUS_ERROR now
> serves the explicit purpose of noting a failure to find a previously mounted
> filesytem/directory after initial freeze, or failure to unfreeze 1 or more
> filesystems.
> - -c/--channel option to qemu-ga is now -m/--method
>
> CHANGES SINCE V5:
> - switched to using qemu malloc/list functions where possible
> - removed unused proxy_path field in struct GAState
> - pid file now opened write-only, removed lockf() in favor of O_EXCL, added
> SIGINT/SIGTERM signal handlers to handle cleanup
> - cleaned up error-handling, switched to asserts where appropriate, removed
> unecessary gotos and NULL checks for qemu_free()/qobject_decref()
> - refactored send_payload() using helper functions
> - fixed improper handling of pidfile fd==0
> - changed guest-shutdown's "shutdown_mode" param to "mode"
> - switched to using kernel-generated FDs for guest-file-open rather than an
> autoincrement value
> - add maximum chunk size of guest-file-read/guest-file-write
> - added checks to avoid guest-file-write from writing data beyond the
> provided data buffer
> - made logging best-effort, removed handling of failures to log as errors
> - guest-shutdown exec errors now logged to guest syslog, clarified
> shutdown's asynchronous, no gauruntee nature in schema.
>
> CHANGES SINCE V4:
> - Removed timeout mechanism via worker thread/pthread_cancel due to
> potential memory leak. Will re-introduce guest-side timeout support in future
> version.
> - Fixed up fsfreeze code to use enums specified within the guest agent's
> qapi schema.
> - Fixed memory leak due to a log statement, and added missing cleanup
> functions for heap-allocated g_error objects.
> - Made "mode" param to guest-file-open optional, defaults to "r" (read-only)
>
> CHANGES SINCE V3:
> - Fixed error-handling issues in fsfreeze commands leading to certain
> mounted directories causing freeze/thaw operations to fail
> - Added cleanup hook to thaw filesystems on graceful guest agent exit
> - Removed unused enum values and added additional details to schema
> documentation
> - Fixed build issue that was missed due to deprecated files in source tree,
> removed unused includes
>
> CHANGES SINCE V2:
> - Rebased on new QAPI code generation framework
> - Dropped ability for QMP to act as a proxy for the guest agent, will be
> added when new QMP server is backported from Anthony's glib tree
> - Replaced negotiation/control events with a simple 2-way handshake
> implemented by a standard RPC (guest-sync)
> - Removed enforcement of "pristine" sessions, state is now global/persistant
> across multiple clients/connections
> - Fixed segfault in logging code
> - Added Jes' filesystem freeze patches
> - General cleanups
>
> CHANGES SINCE V1:
> - Added guest agent worker thread to execute RPCs in the guest. With this in
> place we have a reliable timeout mechanism for hung commands, currently set
> at 30 seconds.
> - Add framework for registering init/cleanup routines for stateful RPCs to
> clean up after themselves after a timeout.
> - Added the following RPCs: guest-file-{open,close,read,write,seek},
> guest-shutdown, guest-info, and removed stubs for guest-view-file (now
> deprecated)
> - Added GUEST_AGENT_UP/GUEST_AGENT_DOWN QMP events
> - Switched to a TCP-style host-initiated 3-way handshake for channel
> negotiation, this simplifies client negotiation/interaction over the wire
> - Added configurable log level/log file/pid file options for guest agent
> - Various fixes for bugs/memory leaks and checkpatch.pl fixups
>
> ISSUES/TODOS:
> - Add unit tests for guest agent wire protocol
>
> OVERVIEW
>
> For a better overview of what these patches are meant to accomplish, please
> reference the RFC for virtagent:
>
> http://comments.gmane.org/gmane.comp.emulators.qemu/96096
>
> These patches integrate the previous virtagent guest agent work directly in
> QAPI/QMP to leverage it's auto-generated marshalling code. This has numerous
> benefits:
>
> - addresses previous concerns over relying on external libraries to handle
> data encapsulation
> - reduces the need for manual unmarshalling of requests/responses, which
> makes adding new RPCs much safer/less error-prone, as well as cutting down on
> redundant code
> - QAPI documentation aligns completely with guest-side RPC implementation
> - is Just Better (TM)
>
> BUILD/USAGE
>
> build:
> ./configure --target-list=x86_64-softmmu
> make
> make qemu-ga #should be built on|for target guest
HI, Macheal.
Is qemu-ga built in guest? if yes, it will require the guest to set up
a gcc environment. Can we make it built on the host?
>
> start guest:
> qemu \
> -drive file=/home/mdroth/vm/rhel6_64_base.raw,snapshot=off,if=virtio \
> -net nic,model=virtio,macaddr=52:54:00:12:34:00 \
> -net tap,script=/etc/qemu-ifup \
> -vnc :1 -m 1024 --enable-kvm \
> -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 \
> -device virtio-serial \
> -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0"
>
> use guest agent:
> ./qemu-ga -h
> ./qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0
>
> start/use qmp:
> address@hidden:~$ sudo socat unix-connect:/tmp/qga.sock readline
> {"execute":"guest-sync", "arguments":{"id":1234}}
> {"return": 1234}
>
> {"execute":"guest-ping"}
> {"return": {}}
>
> {"execute": "guest-info"}
> {"return": {"version": "1.0"}}
>
> // write "hello world!\n" to /tmp/testqga
> {"execute":"guest-file-open",
> "arguments":{"path":"/tmp/testqga","mode":"w+"}}
> {"return": 0}
> {"execute":"guest-file-write",
> "arguments":{"handle":0,"buf-b64":"aGVsbG8gd29ybGQhCg=="}}
> {"return": {"count": 13, "eof": false}}
> {"execute":"guest-file-close", "arguments":{"handle":0}}
> {"return": {}}
>
> // read back the "hello world!\n" from /tmp/testqga
> {"execute":"guest-file-open", "arguments":{"path":"/tmp/testqga","mode":"r"}}
> {"return": 1}
> {"execute":"guest-file-read", "arguments":{"handle":1,"count":1024}}
> {"return": {"buf-b64": "aGVsbG8gd29ybGQhCg==", "count": 13, "eof": true}}
> {"execute":"guest-file-close","arguments":{"handle":1}}
> {"return": {}}
>
> Makefile | 25 ++-
> configure | 1 +
> qapi-schema-guest.json | 217 +++++++++++++
> qemu-ga.c | 671
> +++++++++++++++++++++++++++++++++++++++
> qerror.c | 13 +
> qerror.h | 6 +
> qga/guest-agent-command-state.c | 73 +++++
> qga/guest-agent-commands.c | 512 +++++++++++++++++++++++++++++
> qga/guest-agent-core.h | 31 ++
> 9 files changed, 1544 insertions(+), 5 deletions(-)
>
>
>
--
Regards,
Zhi Yong Wu