Re: [Qemu-devel] [PATCH 4/5] target-arm: get_phys_addr_lpae: more xn control

[Peter Maydell]

On 10 March 2015 at 17:02, Andrew Jones <address@hidden> wrote:
> On Tue, Mar 10, 2015 at 04:55:53PM +0000, Peter Maydell wrote:
>> On 10 March 2015 at 16:48, Andrew Jones <address@hidden> wrote:
>> > On Tue, Mar 10, 2015 at 03:56:11PM +0000, Peter Maydell wrote:
>>
>> >> For instance, you're missing a shift here on the ap bits, because
>> >> get_rw_prot needs AP[2:0] and 'ap' here is AP[2:1].
>> >
>> > Don't need the shift because get_rw_prot supports the 2-bit format.
>>
>> No it doesn't...
>
> Yes it does :-) That's the support patch 2/5 adds.

No, because patch 2 doesn't do anything in the callers to
make them pass only bits [2:1]. So after patch 2 get_rw_prot
still requires bits [2:0]. Except it's broken, because the
function itself assumes it gets bits [2:1].

Having thought a bit more about it, I think we should
just have two totally separate functions for the old
style and simplified permission checks, because we can
always call the correct one (always old for v5, either
one for v6 since we already have the SCTLR.AFE check,
and the simplified one for the lpae code path).

-- PMM