Re: [PATCH 1/2] KVM: PPC: bookehv: Fix r8/r13 storing in level exception handler

[Scott Wood <scottwood@freescale.com>]

On 04/26/2012 06:36 AM, Alexander Graf wrote:
> 
> On 16.04.2012, at 16:08, Mihai Caraman wrote:
> 
>> Guest r8 register is held in the scratch register and stored correctly,
>> so remove the instruction that clobbers it. Guest r13 was missing from vcpu,
>> store it there.
>>
>> Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
>> ---
>> arch/powerpc/kvm/bookehv_interrupts.S |    2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S
>> index 0d04bc9..0ca987d 100644
>> --- a/arch/powerpc/kvm/bookehv_interrupts.S
>> +++ b/arch/powerpc/kvm/bookehv_interrupts.S
>> @@ -264,10 +264,10 @@ _GLOBAL(kvmppc_handler_\intno\()_\srr1)
>> 	mfspr	r6, \srr1
>> 	PPC_LL	r4, GPR11(r8)
>> 	PPC_STL	r7, VCPU_GPR(r7)(r11)
>> -	PPC_STL	r8, VCPU_GPR(r8)(r11)
> 
> I'm not sure I can follow you here. The code that leads up to this is:
> 
> #define NORMAL_EXCEPTION_PROLOG(intno)                                               \
>         mtspr   SPRN_SPRG_WSCRATCH0, r10;       /* save one register */      \
>         mfspr   r10, SPRN_SPRG_THREAD;                                       \
>         stw     r11, THREAD_NORMSAVE(0)(r10);                                \
>         stw     r13, THREAD_NORMSAVE(2)(r10);                                \
>         mfcr    r13;                    /* save CR in r13 for now          */\
>         mfspr   r11, SPRN_SRR1;                                              \
>         DO_KVM  BOOKE_INTERRUPT_##intno SPRN_SRR1;                           \

See the subject line -- this is for level exceptions
(EXC_LEVEL_EXCEPTION_PROLOG), not normal exceptions.

-Scott