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From: Marc Zyngier <maz@kernel.org>
To: Sebastian Ott <sebott@redhat.com>
Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
	kvmarm@lists.linux.dev, oliver.upton@linux.dev,
	catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
	Cornelia Huck <cohuck@redhat.com>,
	eric.auger@redhat.com, yuzenghui@huawei.com,
	wangzhou1@hisilicon.com, jiangkunkun@huawei.com,
	jonathan.cameron@huawei.com, anthony.jebson@huawei.com,
	linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com
Subject: Re: [PATCH v5 0/4] KVM: arm64: Errata management for VM Live migration
Date: Tue, 04 Feb 2025 17:11:33 +0000	[thread overview]
Message-ID: <8634gtvdmi.wl-maz@kernel.org> (raw)
In-Reply-To: <76172c57-aac6-d540-5b98-8de100c0886c@redhat.com>

On Tue, 04 Feb 2025 16:45:38 +0000,
Sebastian Ott <sebott@redhat.com> wrote:
> 
> Hey,
> 
> On Fri, 24 Jan 2025, Shameer Kolothum wrote:
> > On ARM64 platforms most of the errata workarounds are based on CPU
> > MIDR/REVIDR values and a number of these workarounds need to be
> > implemented by the Guest kernel as well. This creates a problem when
> > Guest needs to be migrated to a platform that differs in these
> > MIDR/REVIDR values even if the VMM can come up with a common minimum
> > feature list for the Guest using the recently introduced "Writable
> > ID registers" support.
> 
> Currently MIDR/REVIDR are still RO and guest access is not trapped - so
> even with the errata management patches in place the guest state would
> change and a migration (between hosts that differ in these regs) would
> not be possible. Are there any plans to allow to actually change these?

Sure thing. We only need a victim! :)

	M.

-- 
Without deviation from the norm, progress is not possible.


  reply	other threads:[~2025-02-04 17:13 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-24 15:17 [PATCH v5 0/4] KVM: arm64: Errata management for VM Live migration Shameer Kolothum
2025-01-24 15:17 ` [PATCH v5 1/4] arm64: Modify _midr_range() functions to read MIDR/REVIDR internally Shameer Kolothum
2025-01-24 15:17 ` [PATCH v5 2/4] KVM: arm64: Introduce hypercall support for retrieving target implementations Shameer Kolothum
2025-01-27 12:50   ` Cornelia Huck
2025-01-27 17:26   ` Oliver Upton
2025-01-28 14:16     ` Shameerali Kolothum Thodi
2025-01-24 15:17 ` [PATCH v5 3/4] KVM: arm64: Report all the KVM/arm64-specific hypercalls Shameer Kolothum
2025-01-27 12:47   ` Cornelia Huck
2025-01-27 13:35     ` Shameerali Kolothum Thodi
2025-01-27 17:05   ` Oliver Upton
2025-01-27 17:24     ` Shameerali Kolothum Thodi
2025-01-24 15:17 ` [PATCH v5 4/4] arm64: paravirt: Enable errata based on implementation CPUs Shameer Kolothum
2025-01-27 12:53   ` Cornelia Huck
2025-01-27 17:37   ` Oliver Upton
2025-02-04 16:45 ` [PATCH v5 0/4] KVM: arm64: Errata management for VM Live migration Sebastian Ott
2025-02-04 17:11   ` Marc Zyngier [this message]
2025-02-04 17:42     ` Sebastian Ott
2025-02-04 18:15       ` Marc Zyngier

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