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| author | Punit Agrawal <punit.agrawal@arm.com> | 2018-08-13 11:43:51 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-08-13 15:32:01 +0100 |
| commit | 976d34e2dab10ece5ea8fe7090b7692913f89084 (patch) | |
| tree | 116675a97ba2812fccb4aec6119786eb2b452b1d | |
| parent | 86658b819cd0a9aa584cd84453ed268a6f013770 (diff) | |
| download | linux-976d34e2dab10ece5ea8fe7090b7692913f89084.tar.bz2 | |
KVM: arm/arm64: Skip updating PTE entry if no change
When there is contention on faulting in a particular page table entry
at stage 2, the break-before-make requirement of the architecture can
lead to additional refaulting due to TLB invalidation.
Avoid this by skipping a page table update if the new value of the PTE
matches the previous value.
Cc: stable@vger.kernel.org
Fixes: d5d8184d35c9 ("KVM: ARM: Memory virtualization setup")
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| -rw-r--r-- | virt/kvm/arm/mmu.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 13dfe36501aa..91aaf73b00df 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1147,6 +1147,10 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, /* Create 2nd stage page table mapping - Level 3 */ old_pte = *pte; if (pte_present(old_pte)) { + /* Skip page table update if there is no change */ + if (pte_val(old_pte) == pte_val(*new_pte)) + return 0; + kvm_set_pte(pte, __pte(0)); kvm_tlb_flush_vmid_ipa(kvm, addr); } else { |