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From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	LAKML <linux-arm-kernel@lists.infradead.org>,
	KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v3 1/1] irqchip/gic-v4.1: Disable vSGI upon (GIC CPUIF < v4.1) detection
Date: Wed, 17 Mar 2021 14:40:04 +0000	[thread overview]
Message-ID: <20210317144004.GA6593@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <87blbhj2q3.wl-maz@kernel.org>

On Wed, Mar 17, 2021 at 02:04:36PM +0000, Marc Zyngier wrote:
> Hi Lorenzo,
> 
> Wed, 17 Mar 2021 10:07:19 +0000,
> Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote:
> > 
> > GIC CPU interfaces versions predating GIC v4.1 were not built to
> > accommodate vINTID within the vSGI range; as reported in the GIC
> > specifications (8.2 "Changes to the CPU interface"), it is
> > CONSTRAINED UNPREDICTABLE to deliver a vSGI to a PE with
> > ID_AA64PFR0_EL1.GIC < b0011.
> > 
> > Check the GIC CPUIF version by reading the SYS_ID_AA64_PFR0_EL1.
> > 
> > Disable vSGIs if a CPUIF version < 4.1 is detected to prevent using
> > vSGIs on systems where they may misbehave.
> > 
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Marc Zyngier <maz@kernel.org>
> 
> Does it need to go in as a fix? or can it just be pushed into 5.13?
> Given that there is no such HW in the wild just yet, I'm inclined to
> do the latter...

I agree with you; it is to make the driver/vgic robust against HW
misconfigurations (because that's what they are and I am not aware of
any _existing_ HW with such a misconfiguration - yet), 5.13 will
perfectly do.

Thanks a lot.

Lorenzo

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      reply	other threads:[~2021-03-17 14:47 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <0201111162841.3151-1-lorenzo.pieralisi@arm.com>
2021-03-02 10:27 ` [PATCH v2 0/1] GIC v4.1: Disable VSGI support for GIC CPUIF < v4.1 Lorenzo Pieralisi
2021-03-02 10:27   ` [PATCH v2 1/1] irqchip/gic-v4.1: Disable vSGI upon (GIC CPUIF < v4.1) detection Lorenzo Pieralisi
2021-03-08 19:22     ` Marc Zyngier
2021-03-15 11:02       ` Lorenzo Pieralisi
2021-03-17 10:07   ` [PATCH v3 0/1] GIC v4.1: Disable VSGI support for GIC CPUIF < v4.1 Lorenzo Pieralisi
2021-03-17 10:07     ` [PATCH v3 1/1] irqchip/gic-v4.1: Disable vSGI upon (GIC CPUIF < v4.1) detection Lorenzo Pieralisi
2021-03-17 14:04       ` Marc Zyngier
2021-03-17 14:40         ` Lorenzo Pieralisi [this message]

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