Nicholas Piggin <npiggin@xxxxxxxxx> writes:
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 78e6a392330f..0221a0f74f07 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -439,6 +439,9 @@ static inline int try_lock_tlbie(unsigned int *lock)
> unsigned int tmp, old;
> unsigned int token = LOCK_TOKEN;
>
> + if (mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE))
> + return 1;
> +
> asm volatile("1:lwarx %1,0,%2\n"
> " cmpwi cr0,%1,0\n"
> " bne 2f\n"
> @@ -452,6 +455,12 @@ static inline int try_lock_tlbie(unsigned int *lock)
> return old == 0;
> }
>
> +static inline void unlock_tlbie_after_sync(unsigned int *lock)
> +{
> + if (mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE))
> + return;
> +}
So this is a bit hard to follow:
#define MMU_FTRS_DEFAULT_HPTE_ARCH_V2 \
MMU_FTR_HPTE_TABLE | MMU_FTR_PPCAS_ARCH_V2
#define MMU_FTRS_POWER MMU_FTRS_DEFAULT_HPTE_ARCH_V2
#define MMU_FTRS_PPC970 MMU_FTRS_POWER | MMU_FTR_TLBIE_CROP_VA // does NOT
#define MMU_FTRS_POWER5 MMU_FTRS_POWER | MMU_FTR_LOCKLESS_TLBIE
#define MMU_FTRS_POWER6 MMU_FTRS_POWER5 | MMU_FTR_KERNEL_RO | MMU_FTR_68_BIT_VA // includes lockless TLBIE
#define MMU_FTRS_POWER7 MMU_FTRS_POWER6 // includes lockless TLBIE
#define MMU_FTRS_POWER8 MMU_FTRS_POWER6 // includes lockless TLBIE
#define MMU_FTRS_POWER9 MMU_FTRS_POWER6 // includes lockless TLBIE
#define MMU_FTRS_CELL MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | // does NOT
MMU_FTR_CI_LARGE_PAGE
#define MMU_FTRS_PA6T MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \ // does NOT
MMU_FTR_CI_LARGE_PAGE | MMU_FTR_NO_SLBIE_B
So it's only 970, Cell and Pasemi that *don't* have lockless TLBIE.
And KVM HV doesn't doesn't run on any of those.
So we can just not check for the feature in the KVM HV code.
Am I right?
cheers
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