From mboxrd@z Thu Jan  1 00:00:00 1970
From: Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v2] kvm: arm64: vgic: fix hyp panic with 64k pages on
 juno platform
Date: Fri, 25 Jul 2014 17:38:14 +0100
Message-ID: <20140725163814.GA2268@arm.com>
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Cc: Peter Maydell <peter.maydell@linaro.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"gleb@kernel.org" <gleb@kernel.org>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	kvm-devel <kvm@vger.kernel.org>,
	Christoffer Dall <christoffer.dall@linaro.org>,
	Marc Zyngier <Marc.Zyngier@arm.com>,
	Don Dutile <ddutile@redhat.com>
To: Joel Schopp <joel.schopp@amd.com>
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On Fri, Jul 25, 2014 at 05:24:18PM +0100, Joel Schopp wrote:
> 
> On 07/25/2014 11:02 AM, Peter Maydell wrote:
> > On 25 July 2014 16:56, Joel Schopp <joel.schopp@amd.com> wrote:
> >> The problem with this patch is the gicv is really 8K.  The reason you
> >> would map at a 60K offset (0xf000), and why we do on our SOC, is so that
> >> the 8K gicv would pick up the last 4K from the first page and the first
> >> 4K from the next page.  With your patch it is impossible to map all 8K
> >> of the gicv with 64K pages.
> >>
> >> My SOC which works fine with kvm now will go to not working with kvm
> >> after this patch.
> > Your SOC currently works by fluke because the guest doesn't
> > look at the last 4K of the GICC. If you're happy with it continuing
> > to work by fluke you could make your device tree say it had a
> > 64K GICV region with a 64K-aligned base.
> >
> > To make it work not by fluke but actually correctly requires
> > Marc's patchset, at a minimum.
> 
> Since we aren't actually using the last 4K of the gicv at the moment I
> supppose I could drop my objections to this patch and change my device
> tree until Marc's patchset provides a proper solution for the gicv's
> second 4K that works for everybody.
> 
> Acked-by: Joel Schopp <joel.schopp@amd.com>

Thanks, Joel.

Will