Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64

[Alexander Graf]

On 20.05.2011, at 05:34, David Gibson wrote:

> Early ppc64 CPUs include a hack to partially simulate the ppc32 segment
> registers, by translating writes to them into writes to the SLB.  This is
> not used by any current Linux kernel, but it is used by the openbios used
> in the qemu mac99 model.
> 
> Commit 81762d6dd0d430d87024f2c83e9c4dcc4329fb7d, cleaning up the SLB
> handling introduced a bug in this code, breaking the openbios currently in
> qemu.  Specifically, there was an off by one error bitshuffling the
> register format used by mtsr into the format needed for the SLB load,
> causing the flag bits to end up in the wrong place.  This caused the
> storage keys to be wrong under openbios, meaning that the translation code
> incorrectly thought a legitimate access was a permission violation.
> 
> This patch fixes the bug, at the same time it fixes some build bug in the
> MMU debugging code (only exposed when DEBUG_MMU is enabled).

Thanks, applied to ppc-next :)


Alex