Re: [Qemu-devel] [PATCH 4/7] ppc: move sdr1 value change detection logic to helper_store_sdr1()

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

On 20/01/15 14:57, Paolo Bonzini wrote:

> On 23/12/2014 01:36, Mark Cave-Ayland wrote:
>> Otherwise when cpu_post_load calls ppc_store_sdr1() when restoring a VM
>> snapshot the value is deemed unchanged and so the internal env->htab*
>> variables aren't set correctly.
>>
>> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>> CC: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  target-ppc/misc_helper.c |    7 ++++++-
>>  target-ppc/mmu_helper.c  |   35 +++++++++++++++--------------------
>>  2 files changed, 21 insertions(+), 21 deletions(-)
>>
>> diff --git a/target-ppc/misc_helper.c b/target-ppc/misc_helper.c
>> index a577b3a..6b12ca8 100644
>> --- a/target-ppc/misc_helper.c
>> +++ b/target-ppc/misc_helper.c
>> @@ -77,8 +77,13 @@ void helper_msr_facility_check(CPUPPCState *env, uint32_t bit,
>>  
>>  void helper_store_sdr1(CPUPPCState *env, target_ulong val)
>>  {
>> +    PowerPCCPU *cpu = ppc_env_get_cpu(env);
>> +
>>      if (!env->external_htab) {
>> -        ppc_store_sdr1(env, val);
>> +        if (env->spr[SPR_SDR1] != val) {
>> +            ppc_store_sdr1(env, val);
>> +            tlb_flush(CPU(cpu), 1);
> 
> Possibly stupid question: should this tlb_flush be in ppc_store_sdr1,
> maybe guarded by "if (tcg_enabled())"?
> 
> Apart from this, the patch is okay.

Thanks Paolo. I based this patch upon a comment in a slightly earlier
thread here:
http://lists.gnu.org/archive/html/qemu-devel/2014-12/msg03146.html.

Is this still relevant or would you still like me to make the change?
This is a little beyond my area of knowledge, but at the very least I
can test any suggested changes under TCG fairly easily.


ATB,

Mark.