[0/3] target/arm: More HCR_EL2.TIDx fixes

Message

Marc Zyngier Nov. 28, 2019, 4:17 p.m. UTC

I started looking the rest of the missing TIDx handling,
and this resulted in the following patches.

There is still one thing I'm a bit puzzled by though:

HCR_EL2.TID0 mandates trapping of the AArch32 JIDR
register, but I couldn't find a trace of it in the QEMU
code, and trying to read it seems to generate an exception.

It isn't like anyone is going to miss it, but I wonder if
it should be implemented... It could also be that I'm missing
the obvious and that my testing is broken! ;-)

Marc Zyngier (3):
  target/arm: Honor HCR_EL2.TID2 trapping requirements
  target/arm: Honor HCR_EL2.TID1 trapping requirements
  target/arm: Handle trapping to EL2 of AArch32 VMRS instructions

 target/arm/helper-a64.h        |  2 ++
 target/arm/helper.c            | 64 ++++++++++++++++++++++++++++++----
 target/arm/internals.h         |  8 +++++
 target/arm/translate-vfp.inc.c | 12 +++++--
 target/arm/vfp_helper.c        | 27 ++++++++++++++
 5 files changed, 103 insertions(+), 10 deletions(-)

Comments

Marc Zyngier Nov. 28, 2019, 4:35 p.m. UTC | #1

On 2019-11-28 16:30, Peter Maydell wrote:
> On Thu, 28 Nov 2019 at 16:17, Marc Zyngier <[e-mail]> wrote:
>>
>> I started looking the rest of the missing TIDx handling,
>> and this resulted in the following patches.
>>
>> There is still one thing I'm a bit puzzled by though:
>>
>> HCR_EL2.TID0 mandates trapping of the AArch32 JIDR
>> register, but I couldn't find a trace of it in the QEMU
>> code, and trying to read it seems to generate an exception.
>>
>> It isn't like anyone is going to miss it, but I wonder if
>> it should be implemented... It could also be that I'm missing
>> the obvious and that my testing is broken! ;-)
>
> Hmm, I was under the impression that we correctly implemented
> 'trivial Jazelle', but we obviously missed some of it
> (we do have the handling of BXJ insns).
> We should, yes, ideally, have RAZ/WI implementations
> of JIDR, JMCR and JOSCR.

OK, I'll have a look at this, and plumb the handling of TID0
in JIDR.

> We also I think don't get right the fiddly detail about
> attempting an exception return with SPSR.J set, but that's
> not worth messing about with IMHO.

Indeed. The less we hear about Jazelle, the better... ;-)

Thanks,

         M.