Re: [PATCH 2/2] KVM: PPC: Book3S HV: lockless tlbie for HPT hcalls
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-04-06 06:12:32
Nicholas Piggin [off-list ref] writes:
quoted hunk ↗ jump to hunk
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