Re: softmmu 'at' instruction support

[Janne Karhunen]

On Fri, Nov 19, 2021 at 12:54 PM Janne Karhunen
<janne.karhunen@gmail.com> wrote:

> So 'at' reads in regime_ttbr:
> 10541         return env->cp15.ttbr0_el[regime_el(env, mmu_idx)];
> (gdb) p/x env->cp15.ttbr0_el[regime_el(env, mmu_idx)]
> $1 = 0x41730000
>
> Which is wrong. The runtime reads:
> 10543         return env->cp15.ttbr1_el[regime_el(env, mmu_idx)];
> (gdb) p/x env->cp15.ttbr1_el[regime_el(env, mmu_idx)]
> $1 = 0x41731001
>
> The determining factor about which one is used is in
> aa64_va_parameters, and it's the bit 55:

I stand corrected - looks like D5.1 in the arch spec does state that
the bit 55 makes the selection.

Interesting. Looks like just padding the address linux style with
0xffff8 is the key to happiness if you expect answers from ttbr1_el1.


--
Janne