From: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
To: Marc Zyngier <maz@kernel.org>
Cc: "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
Linuxarm <linuxarm@huawei.com>
Subject: RE: [PATCH for-stable-5.10 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
Date: Thu, 25 Mar 2021 09:37:15 +0000 [thread overview]
Message-ID: <3ed860eaf93c43969b7dfeb0904efb2e@huawei.com> (raw)
In-Reply-To: <9850fc39c1c80840ea77eba60ee5e663@kernel.org>
> -----Original Message-----
> From: Marc Zyngier [mailto:maz@kernel.org]
> Sent: 25 March 2021 09:33
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> Cc: kvmarm@lists.cs.columbia.edu; kvm@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; stable@vger.kernel.org;
> pbonzini@redhat.com; Linuxarm <linuxarm@huawei.com>
> Subject: Re: [PATCH for-stable-5.10 2/2] KVM: arm64: Workaround firmware
> wrongly advertising GICv2-on-v3 compatibility
>
> On 2021-03-25 09:14, Shameer Kolothum wrote:
> > From: Marc Zyngier <maz@kernel.org>
> >
> > commit 9739f6ef053f104a997165701c6e15582c4307ee upstream.
> >
> > It looks like we have broken firmware out there that wrongly
> > advertises a GICv2 compatibility interface, despite the CPUs not being
> > able to deal with it.
> >
> > To work around this, check that the CPU initialising KVM is actually
> > able to switch to MMIO instead of system registers, and use that as a
> > precondition to enable GICv2 compatibility in KVM.
> >
> > Note that the detection happens on a single CPU. If the firmware is
> > lying *and* that the CPUs are asymetric, all hope is lost anyway.
> >
> > Cc: stable@vger.kernel.org #5.10
> > Reported-by: Shameerali Kolothum Thodi
> > <shameerali.kolothum.thodi@huawei.com>
> > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > Message-Id: <20210305185254.3730990-8-maz@kernel.org>
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>
> Please hold on on that.
>
> This patch causes a regression, and needs a fix that is currently queued for 5.12
> [1]. Once this hits upstream, please add the fix to the series and post it as a
> whole.
Ok. Yes, I noted that. But was thinking if this goes through first and then we can have a
stable tag for that one, we can manage it. Anyway, will wait now.
Thanks,
Shameer
> Thanks,
>
> M.
>
> [1] https://lore.kernel.org/r/20210323162301.2049595-1-maz@kernel.org
> --
> Jazz is not dead. It just smells funny...
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next prev parent reply other threads:[~2021-03-25 9:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 9:14 [PATCH for-stable-5.10 0/2] Backport for- Work around firmware wrongly advertising GICv2 compatibility Shameer Kolothum
2021-03-25 9:14 ` [PATCH for-stable-5.10 1/2] KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config() Shameer Kolothum
2021-03-25 9:14 ` [PATCH for-stable-5.10 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility Shameer Kolothum
2021-03-25 9:33 ` Marc Zyngier
2021-03-25 9:37 ` Shameerali Kolothum Thodi [this message]
2021-03-25 9:54 ` Marc Zyngier
2021-03-25 11:38 ` Greg KH
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