[PATCH v2 3/5] ARM: KVM: relax cache maintainance when building page tables

Marc Zyngier marc.zyngier at arm.com
Thu May 2 10:39:00 EDT 2013


Patch 5a677ce044f1 (ARM: KVM: switch to a dual-step HYP init code)
introduced code that flushes page tables to the point of coherency.
This is overkill (point of unification is enough and already done),
and actually not required if running on a SMP capable platform
(the HW PTW can snoop other cpus' L1).

Remove this code and let ae8a8b9553bd (ARM: 7691/1: mm: kill unused
TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead) turn it into
a no-op for SMP ARMv7.

Reported-by: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will.deacon at arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 arch/arm/kvm/mmu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 4a838db..d79b594 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -234,7 +234,6 @@ static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
 		pte = pte_offset_kernel(pmd, addr);
 		kvm_set_pte(pte, pfn_pte(pfn, prot));
 		get_page(virt_to_page(pte));
-		kvm_flush_dcache_to_poc(pte, sizeof(*pte));
 		pfn++;
 	} while (addr += PAGE_SIZE, addr != end);
 }
@@ -261,7 +260,6 @@ static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
 			}
 			pmd_populate_kernel(NULL, pmd, pte);
 			get_page(virt_to_page(pmd));
-			kvm_flush_dcache_to_poc(pmd, sizeof(*pmd));
 		}
 
 		next = pmd_addr_end(addr, end);
@@ -299,7 +297,6 @@ static int __create_hyp_mappings(pgd_t *pgdp,
 			}
 			pud_populate(NULL, pud, pmd);
 			get_page(virt_to_page(pud));
-			kvm_flush_dcache_to_poc(pud, sizeof(*pud));
 		}
 
 		next = pgd_addr_end(addr, end);
-- 
1.8.2.1





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