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| author | Punit Agrawal <punit.agrawal@arm.com> | 2018-08-13 11:43:51 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-05 09:29:43 +0200 |
| commit | 1d0bd8c92361c2a97fcdd38fa2302ef8e3e746f2 (patch) | |
| tree | de74e7b5cd089fed5b1cf2bb30c649b0f5d21539 /virt | |
| parent | c7bcb09e4e353f11162fd16b93f181305edcc21d (diff) | |
| download | linux-stable-1d0bd8c92361c2a97fcdd38fa2302ef8e3e746f2.tar.gz linux-stable-1d0bd8c92361c2a97fcdd38fa2302ef8e3e746f2.tar.bz2 linux-stable-1d0bd8c92361c2a97fcdd38fa2302ef8e3e746f2.zip | |
KVM: arm/arm64: Skip updating PTE entry if no change
commit 976d34e2dab10ece5ea8fe7090b7692913f89084 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
| -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 2bb0b5dba412..c2b95a22959b 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1118,6 +1118,10 @@ 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 { |