Re: [PATCH v2 02/11] target/arm: enable tracking of CPU index in MemTxAttrs

["Alex Bennée" <alex.bennee@linaro.org>]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Mon, 26 Sept 2022 at 14:39, Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>> Both arm_cpu_tlb_fill (for normal IO) and
>> arm_cpu_get_phys_page_attrs_debug (for debug access) come through
>> get_phys_addr which is setting the other memory attributes for the
>> transaction. As these are all by definition CPU accesses we can also
>> set the requested_type/index as appropriate.
>>
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> ---
>>  target/arm/ptw.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/target/arm/ptw.c b/target/arm/ptw.c
>> index 3261039d93..644d450662 100644
>> --- a/target/arm/ptw.c
>> +++ b/target/arm/ptw.c
>> @@ -2315,6 +2315,9 @@ bool get_phys_addr(CPUARMState *env, target_ulong address,
>>  {
>>      ARMMMUIdx s1_mmu_idx = stage_1_mmu_idx(mmu_idx);
>>
>> +    attrs->requester_type = MEMTXATTRS_CPU;
>> +    attrs->requester_id = env_cpu(env)->cpu_index;
>> +
>
> This only catches the case where the memory access is
> done via something that does a virtual-to-physical translation.
> It misses memory accesses done directly on physical addresses,
> such as those in arm_ldl_ptw() and arm_ldq_ptw(), plus various
> M-profile specific ones.

I thought they were just used for the page table walk. Can you place
your page tables aliases with a piece of HW?

>
> thanks
> -- PMM


-- 
Alex Bennée