Re: [PATCH rfcv3 07/11] qemu: add hard reboot in QEMU driver
On Fri, Jan 12, 2024 at 09:20:19AM +0000, Duan, Zhenzhong wrote:
>-----Original Message-----
>From: Daniel P. Berrangé <berrange(a)redhat.com>
>Subject: Re: [PATCH rfcv3 07/11] qemu: add hard reboot in QEMU driver
>
>On Mon, Nov 27, 2023 at 04:55:17PM +0800, Zhenzhong Duan wrote:
>> From: Chenyi Qiang <chenyi.qiang(a)intel.com>
>>
>> Add the new flag
>VIR_DOMAIN_REBOOT_HARD/VIR_DOMAIN_SHUTDOWN_HARD to
>> carry out a hard reboot, which kills the QEMU process and creates a new
>> one with the same definition.
>
>AFAICT, the _HARD flags cause it to issue a QEMU monitor
>command todo an ACPI shutdown and then re-create QEMU.
>
>IOW, it seems like this is just the same as the existing
>_ACPI flags, and so I'm not sure why we need any new
>functionality at all.
>
>What is the existing ACPI shutdown & fake reboot not
>able to achieve ?
ACPI shutdown & fake reboot send below QMP command in sequence:
"system_powerdown", "system_reset", "cont".
"system_reset" QMP command isn't supported by TDX for security reasons.
So we have to kill old QEMU and re-create new one.
We are still doing the 'system_powerdown' step first though, to do a
graceful shutdown, before re-creating QEMU, and the powerdown is what
we refer to as "ACPI".
So I think we don't need new public API constants. We should still use
the _ACPI flag, and just "do the right thing" with choosing between
system_reset vs re-creating QEMU depending on whether TDX/SEV are
active.
That way the public API user experience is unchanged, only the internal
impl varies.
With regards,
Daniel
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