[PATCH for-stable-5.10 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility

[Greg KH]

On Thu, Mar 25, 2021 at 09:33:17AM +0000, Marc Zyngier wrote:
> On 2021-03-25 09:14, Shameer Kolothum wrote:
> > From: Marc Zyngier <maz at 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 at vger.kernel.org #5.10
> > Reported-by: Shameerali Kolothum Thodi
> > <shameerali.kolothum.thodi at huawei.com>
> > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
> > Signed-off-by: Marc Zyngier <maz at kernel.org>
> > Message-Id: <20210305185254.3730990-8-maz at kernel.org>
> > Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi at 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.

Both patches now dropped from my queue, thanks.

greg k-h