From: Steven Sistare <steven.sistare@oracle.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Daniel P. Berrange" <berrange@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, "Markus Armbruster" <armbru@redhat.com>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>
Subject: Re: [PATCH V1 05/32] savevm: QMP command for cprload
Date: Thu, 24 Sep 2020 17:49:58 -0400 [thread overview]
Message-ID: <d991fe19-d5a9-36a7-3d8f-0730fe9da06b@oracle.com> (raw)
In-Reply-To: <20200911171809.GM3310@work-vm>
On 9/11/2020 1:18 PM, Dr. David Alan Gilbert wrote:
> * Steven Sistare (steven.sistare@oracle.com) wrote:
>> On 7/30/2020 12:14 PM, Eric Blake wrote:
>>> On 7/30/20 10:14 AM, Steve Sistare wrote:
>>>> Provide the cprload QMP command. The VM is created from the file produced
>>>> by the cprsave command. Guest RAM is restored in-place from the shared
>>>> memory backend file, and guest block devices are used as is. The contents
>>>> of such devices must not be modified between the cprsave and cprload
>>>> operations. If the VM was running at cprsave time, then VM execution
>>>> resumes.
>>>
>>> Is it always wise to unconditionally resume, or might this command need an additional optional knob that says what state (paused or running) to move into?
>>
>> This can already be done. Issue a stop command before cprsave, then cprload will finish in a
>> paused state.
>>
>> Also, cprsave re-execs and leaves the guest in a paused state. One can
>>
>> send device add commands, then send cprload which continues
>> .
>
> You're suffering here because you're reinventing stuff rather than
> reusing existing migration paths.
> With the existing migration code we require the qemu
> to be started with -incoming ... so we know it's in a clean
> state ready for being loaded, and we've already got the -S
> mechanism that dictates whether or not the VM autostarts
> (regardless of the saved state in the image). The management
> layers find this pretty useful if they need to wire some networking
> or storage up at the point they know they've got a VM image that's
> loaded OK.
I am not seeing the issue here. The manager can hot plug with cprsave as
easily as with migration, at the same transition points. I don't see what
migration paths should be reused here.
CPR Migration
- cprsave restarts qemu with the env - qemu -S -incoming defer
var QEMU_START_FREEZE set, which
clears autostart just like -S.
(see patch 15)
- command-line devices created - command-line devices created
- vmstate is prelaunch - vmstate is inmigrate
- manager sends hotplug commands - manager sends hotplug commands
- manager sends cprload - manager sends migrate_incoming
It would perhaps be more correct for cprsave to leave the vm in the preconfig
state.
I don't feel like I'm suffering. At least not yet :)
- Steve
>>>> Syntax:
>>>> Â Â {'command':'cprload', 'data':{'file':'str'}}
>>>>
>>>> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
>>>> Signed-off-by: Maran Wilson <maran.wilson@oracle.com>
>>>> ---
>>>
>>>> +++ b/qapi/migration.json
>>>> @@ -1635,3 +1635,14 @@
>>>> Â ##
>>>> Â { 'command': 'cprsave', 'data': { 'file': 'str', 'mode': 'str' } }
>>>> Â +##
>>>> +# @cprload:
>>>> +#
>>>> +# Start virtual machine from checkpoint file that was created earlier using
>>>> +# the cprsave command.
>>>> +#
>>>> +# @file: name of checkpoint file
>>>> +#
>>>> +# Since 5.0
>>>
>>> another 5.2 instance. I'll quit pointing it out for the rest of the series.
>>
>> Will find and fix all, thanks.
>>
>> - Steve
>>
next prev parent reply other threads:[~2020-09-24 21:50 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 15:14 [PATCH V1 00/32] Live Update Steve Sistare
2020-07-30 15:14 ` [PATCH V1 01/32] savevm: add vmstate handler iterators Steve Sistare
2020-09-11 16:24 ` Dr. David Alan Gilbert
2020-09-24 21:43 ` Steven Sistare
2020-09-25 9:07 ` Dr. David Alan Gilbert
2020-07-30 15:14 ` [PATCH V1 02/32] savevm: VM handlers mode mask Steve Sistare
2020-07-30 15:14 ` [PATCH V1 03/32] savevm: QMP command for cprsave Steve Sistare
2020-07-30 16:12 ` Eric Blake
2020-07-30 17:52 ` Steven Sistare
2020-09-11 16:43 ` Dr. David Alan Gilbert
2020-09-25 18:43 ` Steven Sistare
2020-09-25 22:22 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 04/32] savevm: HMP Command " Steve Sistare
2020-09-11 16:57 ` Dr. David Alan Gilbert
2020-09-24 21:44 ` Steven Sistare
2020-09-25 9:26 ` Dr. David Alan Gilbert
2020-07-30 15:14 ` [PATCH V1 05/32] savevm: QMP command for cprload Steve Sistare
2020-07-30 16:14 ` Eric Blake
2020-07-30 18:00 ` Steven Sistare
2020-09-11 17:18 ` Dr. David Alan Gilbert
2020-09-24 21:49 ` Steven Sistare [this message]
2020-07-30 15:14 ` [PATCH V1 06/32] savevm: HMP Command " Steve Sistare
2020-07-30 15:14 ` [PATCH V1 07/32] savevm: QMP command for cprinfo Steve Sistare
2020-07-30 16:17 ` Eric Blake
2020-07-30 18:02 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 08/32] savevm: HMP " Steve Sistare
2020-09-11 17:27 ` Dr. David Alan Gilbert
2020-09-24 21:50 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 09/32] savevm: prevent cprsave if memory is volatile Steve Sistare
2020-09-11 17:35 ` Dr. David Alan Gilbert
2020-09-24 21:51 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 10/32] kvmclock: restore paused KVM clock Steve Sistare
2020-09-11 17:50 ` Dr. David Alan Gilbert
2020-09-25 18:07 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 11/32] cpu: disable ticks when suspended Steve Sistare
2020-09-11 17:53 ` Dr. David Alan Gilbert
2020-09-24 20:42 ` Steven Sistare
2020-09-25 9:03 ` Dr. David Alan Gilbert
2020-07-30 15:14 ` [PATCH V1 12/32] vl: pause option Steve Sistare
2020-07-30 16:20 ` Eric Blake
2020-07-30 18:11 ` Steven Sistare
2020-07-31 10:07 ` Daniel P. Berrangé
2020-07-31 15:18 ` Steven Sistare
2020-07-30 17:03 ` Alex Bennée
2020-07-30 18:14 ` Steven Sistare
2020-07-31 9:44 ` Alex Bennée
2020-09-11 17:59 ` Dr. David Alan Gilbert
2020-09-24 21:51 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 13/32] gdbstub: gdb support for suspended state Steve Sistare
2020-09-11 18:41 ` Dr. David Alan Gilbert
2020-09-24 21:51 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 14/32] savevm: VMS_RESTART and cprsave restart Steve Sistare
2020-07-30 16:22 ` Eric Blake
2020-07-30 18:14 ` Steven Sistare
2020-09-11 18:44 ` Dr. David Alan Gilbert
2020-09-24 21:44 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 15/32] vl: QEMU_START_FREEZE env var Steve Sistare
2020-09-11 18:49 ` Dr. David Alan Gilbert
2020-09-24 21:47 ` Steven Sistare
2020-09-25 15:52 ` Dr. David Alan Gilbert
2020-07-30 15:14 ` [PATCH V1 16/32] oslib: add qemu_clr_cloexec Steve Sistare
2020-09-11 18:52 ` Dr. David Alan Gilbert
2020-07-30 15:14 ` [PATCH V1 17/32] util: env var helpers Steve Sistare
2020-09-11 19:00 ` Dr. David Alan Gilbert
2020-09-24 21:52 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 18/32] osdep: import MADV_DOEXEC Steve Sistare
2020-08-17 18:30 ` Steven Sistare
2020-08-17 20:48 ` Alex Williamson
2020-08-17 21:20 ` Steven Sistare
2020-08-17 21:44 ` Alex Williamson
2020-08-18 2:42 ` Alex Williamson
2020-08-19 21:52 ` Steven Sistare
2020-08-24 22:30 ` Alex Williamson
2020-10-08 16:32 ` Steven Sistare
2020-10-15 20:36 ` Alex Williamson
2020-10-19 16:33 ` Steven Sistare
2020-10-26 18:28 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 19/32] memory: ram_block_add cosmetic changes Steve Sistare
2020-07-30 15:14 ` [PATCH V1 20/32] vl: add helper to request re-exec Steve Sistare
2020-07-30 15:14 ` [PATCH V1 21/32] exec, memory: exec(3) to restart Steve Sistare
2020-07-30 15:14 ` [PATCH V1 22/32] char: qio_channel_socket_accept reuse fd Steve Sistare
2020-09-15 17:33 ` Dr. David Alan Gilbert
2020-09-15 17:53 ` Daniel P. Berrangé
2020-09-24 21:54 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 23/32] char: save/restore chardev socket fds Steve Sistare
2020-07-30 15:14 ` [PATCH V1 24/32] ui: save/restore vnc " Steve Sistare
2020-07-31 9:06 ` Daniel P. Berrangé
2020-07-31 16:51 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 25/32] char: save/restore chardev pty fds Steve Sistare
2020-07-30 15:14 ` [PATCH V1 26/32] monitor: save/restore QMP negotiation status Steve Sistare
2020-07-30 15:14 ` [PATCH V1 27/32] vhost: reset vhost devices upon cprsave Steve Sistare
2020-07-30 15:14 ` [PATCH V1 28/32] char: restore terminal on restart Steve Sistare
2020-07-30 15:14 ` [PATCH V1 29/32] pci: export pci_update_mappings Steve Sistare
2020-07-30 15:14 ` [PATCH V1 30/32] vfio-pci: save and restore Steve Sistare
2020-08-06 10:22 ` Jason Zeng
2020-08-07 20:38 ` Steven Sistare
2020-08-10 3:50 ` Jason Zeng
2020-08-19 21:15 ` Steven Sistare
2020-08-20 10:33 ` Jason Zeng
2020-10-07 21:25 ` Steven Sistare
2020-07-30 15:14 ` [PATCH V1 31/32] vfio-pci: trace pci config Steve Sistare
2020-07-30 15:14 ` [PATCH V1 32/32] vfio-pci: improved tracing Steve Sistare
2020-09-15 18:49 ` Dr. David Alan Gilbert
2020-09-24 21:52 ` Steven Sistare
2020-07-30 16:52 ` [PATCH V1 00/32] Live Update Daniel P. Berrangé
2020-07-30 18:48 ` Steven Sistare
2020-07-31 8:53 ` Daniel P. Berrangé
2020-07-31 15:27 ` Steven Sistare
2020-07-31 15:52 ` Daniel P. Berrangé
2020-07-31 17:20 ` Steven Sistare
2020-08-11 19:08 ` Dr. David Alan Gilbert
2020-07-30 17:15 ` Paolo Bonzini
2020-07-30 19:09 ` Steven Sistare
2020-07-30 21:39 ` Paolo Bonzini
2020-07-31 19:22 ` Steven Sistare
2020-07-30 17:49 ` Dr. David Alan Gilbert
2020-07-30 19:31 ` Steven Sistare
2020-08-04 18:18 ` Steven Sistare
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