diff options
| author | Punit Agrawal <punit.agrawal@arm.com> | 2018-08-13 11:43:51 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-05 09:26:36 +0200 |
| commit | 4a06fdf2c490666e7e8d2a3c17adfff3f0354441 (patch) | |
| tree | 79cf9dcf49b1af3ef9cf10ce2a99451675a45dcb | |
| parent | 792a039415dc4562918abff4740ed04c2034f55b (diff) | |
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>
| -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 d88f1e3fa52c..ec275b8472a9 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -985,6 +985,10 @@ 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 { |