From: Marc Zyngier <maz@kernel.org>
To: Andrew Jones <drjones@redhat.com>
Cc: kvmarm <kvmarm@lists.cs.columbia.edu>,
xu910121@sina.com, qemu-devel <qemu-devel@nongnu.org>,
"Dave.Martin" <dave.martin@arm.com>
Subject: Re: Kernel patch cases qemu live migration failed.
Date: Thu, 15 Oct 2020 14:52:34 +0100 [thread overview]
Message-ID: <16400df4bdf79b8b22e824eb1a20e2b4@kernel.org> (raw)
In-Reply-To: <20201015133505.ubxvbrt6xyvl4362@kamzik.brq.redhat.com>
On 2020-10-15 14:35, Andrew Jones wrote:
> On Thu, Oct 15, 2020 at 12:26:10PM +0100, Marc Zyngier wrote:
>> Hi
>>
>> Please don't use my arm.com address anymore, nobody reads it...
>>
>> On 2020-10-15 05:06, 张东旭 wrote:
>> > I'm so sorry for disturbing you.
>> >
>> > When I apply this kernel patch：KVM: arm64/sve: System register
>> > context switch and access support
>> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/kvm/sys_regs.c?id=73433762fcaeb9d59e84d299021c6b15466c96dd
>>
>> This patch was only introduced in 5.2, and wasn't supposed to be
>> backported to anything else.
>
> All upstream patches are backport candidates. Welcome to RHEL :-)
Great! RHEL gets to keep the pieces! ;-)
>
>>
>> > qemu live migration will failed with messages：
>> > qemu-kvm: Invalid value 233 expecting positive value
>> > <= 232
>> > qemu-kvm: Failed to load cpu:cpreg_vmstate_array_len
>> > New version kernel exclude ID_AA64ZFR0_EL1 register when host not
>> > support SVE feature,
>> > so qemu ioctl kvm(KVM_GET_REG_LIST) will not contain ID_AA64ZFR0_EL1
>> > register.
>> >
>> > I'm using CentOS Linux kernel, old kernel version：4.18.0-80.11.el8
>> > (migration source)
>> > new kernel version：4.18.0-147.5.el8 (migration destination)
>> >
>> > CentOS linux kernel version 4.18.0-111.el8 applied this patch. So
>> > 4.18.0-147.5.el8 also applied this patch.
>> >
>> > Migration source and destination hosts have the same hardware, just
>> > kernel version is different,
>> > and the hardware on either side of the migration not support SVE.
>> >
>> > Is there some good suggestions，which can make sure old version
>> > kernel live migration to new version kernel with qemu?
>>
>> I['m afraid you should take this with your distribution of
>> choice, unless you can reproduce the problem with mainline kernels.
>
> I'll bet this reproduces when migrating from a mainline pre SVE
> register
> filtering kernel to a mainline that does the filtering. I don't have
> time to test that though.
Probably. I'm not really sure where to find SVE HW though, other
than emulation...
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-10-15 14:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 4:06 Kernel patch cases qemu live migration failed 张东旭
2020-10-15 11:26 ` Marc Zyngier
2020-10-15 13:35 ` Andrew Jones
2020-10-15 13:52 ` Marc Zyngier [this message]
2020-10-15 14:41 ` Andrew Jones
2020-10-15 14:57 ` Peter Maydell
2020-10-19 9:25 ` Andrew Jones
2020-10-19 11:32 ` Dave Martin
2020-10-19 11:43 ` Peter Maydell
2020-10-19 13:40 ` Andrew Jones
2020-10-19 14:18 ` Peter Maydell
2020-10-19 14:58 ` Dave Martin
2020-10-19 15:23 ` Andrew Jones
2020-10-19 16:36 ` Dave Martin
2020-10-15 13:26 ` Andrew Jones
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