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Re: [Qemu-devel] Shouldn't cortex-a15 enable ARM_FEATURE_EL2?
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] Shouldn't cortex-a15 enable ARM_FEATURE_EL2? |
Date: |
Fri, 13 May 2016 17:56:35 +0100 |
On 13 May 2016 at 17:41, Andrew Baumann <address@hidden> wrote:
> I'm trying to use the MRS/MSR banked register instructions you
> recently implemented, but found that they raised an undefined
> instruction exception on the cortex-a15 CPU model. This seems to
> be caused by the check in msr_banked_access_decode(), which looks
> for ARM_FEATURE_V8 or ARM_FEATURE_EL2.
>
> The quick kludge below worked for me, but I don't have high
> confidence in its correctness -- the CPU supports the virtualisation
> extensions, but I've no idea whether the rest of qemu is consistent
> with enabling that feature. I guess you have a better idea?
Yeah, this came up earlier this week in the context of the A53
and A57:
https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg01006.html
The short answer is that EL2 support isn't finished yet, and
I don't want to enable the feature until we have something that's
complete enough to be able to run a real guest that uses it.
thanks
-- PMM