Re: [Qemu-devel] [Qemu-ppc] [PULL 04/12] ppc: tlbie, tlbia and tlbisync are HV only

[Cédric Le Goater]

On 06/02/2016 09:45 AM, Mark Cave-Ayland wrote:
> On 02/06/16 08:37, Cédric Le Goater wrote:
>> On 06/02/2016 05:17 AM, David Gibson wrote:
>>> On Wed, Jun 01, 2016 at 08:03:08AM +0100, Mark Cave-Ayland wrote:
>>>> On 01/06/16 03:15, David Gibson wrote:
>>>>
>>>>> On Tue, May 31, 2016 at 11:28:49PM +0100, Mark Cave-Ayland wrote:
>>>>>> On 31/05/16 01:41, David Gibson wrote:
>>>>>>
>>>>>>> From: Benjamin Herrenschmidt <address@hidden>
>>>>>>>
>>>>>>> Not that anything remotely recent supports tlbia but ...
>>>>>>>
>>>>>>> Signed-off-by: Benjamin Herrenschmidt <address@hidden>
>>>>>>> Signed-off-by: David Gibson <address@hidden>
>>>>>>> ---
>>>>>>>  target-ppc/translate.c | 6 +++---
>>>>>>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>>>>>>
>>>>>>> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
>>>>>>> index dfd3010..690ffd2 100644
>>>>>>> --- a/target-ppc/translate.c
>>>>>>> +++ b/target-ppc/translate.c
>>>>>>> @@ -4858,7 +4858,7 @@ static void gen_tlbie(DisasContext *ctx)
>>>>>>>  #if defined(CONFIG_USER_ONLY)
>>>>>>>      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>>>>>>  #else
>>>>>>> -    if (unlikely(ctx->pr)) {
>>>>>>> +    if (unlikely(ctx->pr || !ctx->hv)) {
>>>>>>>          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>>>>>>          return;
>>>>>>>      }
>>>>>>> @@ -4879,7 +4879,7 @@ static void gen_tlbsync(DisasContext *ctx)
>>>>>>>  #if defined(CONFIG_USER_ONLY)
>>>>>>>      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>>>>>>  #else
>>>>>>> -    if (unlikely(ctx->pr)) {
>>>>>>> +    if (unlikely(ctx->pr || !ctx->hv)) {
>>>>>>>          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>>>>>>          return;
>>>>>>>      }
>>>>>>> @@ -4898,7 +4898,7 @@ static void gen_slbia(DisasContext *ctx)
>>>>>>>  #if defined(CONFIG_USER_ONLY)
>>>>>>>      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>>>>>>  #else
>>>>>>> -    if (unlikely(ctx->pr)) {
>>>>>>> +    if (unlikely(ctx->pr || !ctx->hv)) {
>>>>>>>          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>>>>>>          return;
>>>>>>>      }
>>>>>>
>>>>>> Unfortunately this patch breaks qemu-system-ppc for both g3beige and
>>>>>> mac99 under TCG causing a freeze in OpenBIOS when starting
>>>>>> qemu-system-ppc with no parameters.
>>>>>
>>>>> Bother, sorry.
>>>>>
>>>>> I think this is because I applied this without the patch that treats
>>>>> machines with no hypervisor mode (e.g. Apples) as always being in
>>>>> hypervisor mode.
>>>>
>>>> No problem, I can cope for a couple of days or so.
>>>
>>> Cédric,
>>>
>>> Not sure if you've seen this thread, but one of the HV-mode patches
>>> caused a regression on Mac.  I think it's because I didn't include the
>>> other patch which treats Apple-mode PPCs as always having HV=1.
>>
>> I missed that as I didn't put myself in Cc :/ 
>>  
>>> Can you make sending your updated version of that patch a priority,
>>> even if the rest of the batch of HV patches isn't ready yet.
>>
>> sure. I will/should today or tomorrow. I suppose we want these patches :
>>
>>      [05/12] ppc: Fix hreg_store_msr() so that non-HV mode cannot alter 
>> MSR:HV
>>              http://patchwork.ozlabs.org/patch/618083/
>>
>>      [07/12] ppc: Better figure out if processor has HV mode 
>>              http://patchwork.ozlabs.org/patch/618089/
>>
>>
>> Mark,
>>
>> I tried to boot a darwinppc-602.iso with :
>>
>>      qemu-system-ppc -M g3beige -cdrom darwinx86-602.iso -boot d
>>
>> but I get a :
>>
>>      "No valid state has been set by load or ..."
>>
>> or we don't need to go further ? may be I need a newer FW.
> 
> Hmmm that looks like you've got an x86 ISO there which is why
> OpenBIOS/PPC fails to execute the bootloader. The image I use for
> testing can be found here:
> https://opensource.apple.com/static/iso/darwinppc-602.cdr.gz (simply
> gunzip and then rename to .iso).

Got it. much better with ppc :) ppc is not that omnipotent.

>> Could you try the two patches above please ? They apply on top of Dave's
>> ppc-for-2.7-20160531 and seem to have a good behavior with the small test
>> I could do.
> 
> I'll try and take a look tomorrow, however in the meantime see if the
> above image enables you to replicate the issue locally.


so, on top of ppc-for-2.7-20160531, with your fix for :

        ppc: Use split I/D mmu modes to avoid flushes on interrupts

and these two patches :

        [05/12] ppc: Fix hreg_store_msr() so that non-HV mode cannot alter 
MSR:HV
                http://patchwork.ozlabs.org/patch/618083/

        [07/12] ppc: Better figure out if processor has HV mode 
                http://patchwork.ozlabs.org/patch/618089/

The darwin cd boots correctly up to :

        ...
        The following devices are available for installation :

and then loops on something. But I don't get a kernel panic anymore.

Dave, 

I still need to dig the !msr_pr removal.


Thanks,

C.


> ATB,
> 
> Mark.
>