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@xxxxxxxxxxxxx>
> ---
> 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; \
[...]
.macro DO_KVM intno srr1
#ifdef CONFIG_KVM_BOOKE_HV
BEGIN_FTR_SECTION
mtocrf 0x80, r11 /* check MSR[GS] without clobbering reg */
bf 3, kvmppc_resume_\intno\()_\srr1
b kvmppc_handler_\intno\()_\srr1
kvmppc_resume_\intno\()_\srr1:
END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
#endif
.endm
[...]
So where is r8 held in a scratch register here? The only registers that I can see stored in scratch registers are r10, r11, r13
> PPC_STL r3, VCPU_GPR(r10)(r11)
> mfctr r7
> PPC_STL r12, VCPU_GPR(r12)(r11)
> + PPC_STL r13, VCPU_GPR(r13)(r11)
r13 however is in a scratch register / scratch memory location according to the code above :).
Alex
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