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Re: [Xen-devel] [PATCH v2 04/15] xen: arm: add a quirk to handle platforms with unusual GIC layout

On 11/22/2013 05:03 PM, Ian Campbell wrote:
On Fri, 2013-11-22 at 16:46 +0000, Julien Grall wrote:

On 11/22/2013 04:24 PM, Ian Campbell wrote:
Use this quirk on the xgene platform.

With this quirk you only fix xen GIC. What about dom0/guest GIC ? I know
that Linux is not using the secondary page, but we expose 2 pages
contiguous page. With this quirk the first page is valid ... but the
second page could belong to another device.

Damn, good point.

Can we remove the second page when the quirk is enabled?

I think what I will do is make gicv_setup map the two discontiguous 4K
regions contiguously into the guest space. This is consistent with the
DTB we expose to the guest.

The reason for the discontinuity at the h/w level is (AFAICT) to support
OSes using 64K pages and/or granules. I think we can live without these
for the time being.

I'm fine with this solution as long as we are sure there is no device memory just after the first page.

Julien Grall

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