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From: Oliver Upton <oliver.upton@linux.dev>
To: Jing Zhang <jingzhangos@google.com>
Cc: KVM <kvm@vger.kernel.org>, KVMARM <kvmarm@lists.linux.dev>,
	ARMLinux <linux-arm-kernel@lists.infradead.org>,
	Marc Zyngier <maz@kernel.org>, Oliver Upton <oupton@google.com>,
	Joey Gouly <joey.gouly@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Andre Przywara <andre.przywara@arm.com>,
	Colton Lewis <coltonlewis@google.coma>,
	Raghavendra Rao Ananta <rananta@google.com>
Subject: Re: [PATCH v1 0/4] Fix a bug in VGIC ITS tables' save/restore
Date: Tue, 5 Nov 2024 13:33:37 -0800	[thread overview]
Message-ID: <ZyqPMdH4anLEIq8G@linux.dev> (raw)
In-Reply-To: <20241105193422.1094875-1-jingzhangos@google.com>

Hi Jing,

On Tue, Nov 05, 2024 at 11:34:18AM -0800, Jing Zhang wrote:
> The core issue stems from the static linked list implementation of DTEs/ITEs,
> requiring a full table scan to locate the list head during restoration. This
> scan increases the likelihood of encountering orphaned entries.  To rectify
> this, the patch series introduces a dummy head to the list, enabling immediate
> access to the list head and bypassing the scan. This optimization not only
> resolves the bug but also significantly enhances restore performance,
> particularly in edge cases where valid entries reside at the end of the table.

I think we need a more targeted fix (i.e. Kunkun's patch) to stop the
bleeding + backport it to stable.

Then we can have a separate discussion about improving the save/restore
performance with your approach.

-- 
Thanks,
Oliver

  parent reply	other threads:[~2024-11-05 21:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-05 19:34 [PATCH v1 0/4] Fix a bug in VGIC ITS tables' save/restore Jing Zhang
2024-11-05 19:34 ` [PATCH v1 1/4] KVM: selftests: aarch64: Test VGIC ITS tables save/restore Jing Zhang
2024-11-05 19:34 ` [PATCH v1 2/4] KVM: arm64: vgic-its: Add a dummy DTE/ITE if necessary in ITS tables save operation Jing Zhang
2024-11-05 19:34 ` [PATCH v1 3/4] KVM: arm64: vgic-its: Return device/event id instead of offset in ITS tables restore Jing Zhang
2024-11-05 19:34 ` [PATCH v1 4/4] KVM: arm64: vgic-its: Utilize the dummy entry in ITS tables restoring Jing Zhang
2024-11-05 21:33 ` Oliver Upton [this message]
2024-11-05 21:56   ` [PATCH v1 0/4] Fix a bug in VGIC ITS tables' save/restore Jing Zhang
2024-11-05 21:58     ` Oliver Upton

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