[PULL,19/28] KVM: arm/arm64: Only clean the dcache on translation fault
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Message ID 20180131093507.22219-20-christoffer.dall@linaro.org
State New
Headers show

Commit Message

Christoffer Dall Jan. 31, 2018, 9:34 a.m. UTC
From: Marc Zyngier <marc.zyngier@arm.com>

The only case where we actually need to perform a dcache maintenance
is when we map the page for the first time, and subsequent permission
faults do not require cache maintenance. Let's make it conditional
on not being a permission fault (and thus a translation fault).

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
 virt/kvm/arm/mmu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Patch
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diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 0417c8e2a81c..f956efbd933d 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1400,7 +1400,9 @@  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 			new_pmd = kvm_s2pmd_mkwrite(new_pmd);
 			kvm_set_pfn_dirty(pfn);
 		}
-		clean_dcache_guest_page(vcpu, pfn, PMD_SIZE);
+
+		if (fault_status != FSC_PERM)
+			clean_dcache_guest_page(vcpu, pfn, PMD_SIZE);
 
 		if (exec_fault) {
 			new_pmd = kvm_s2pmd_mkexec(new_pmd);
@@ -1416,7 +1418,9 @@  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 			kvm_set_pfn_dirty(pfn);
 			mark_page_dirty(kvm, gfn);
 		}
-		clean_dcache_guest_page(vcpu, pfn, PAGE_SIZE);
+
+		if (fault_status != FSC_PERM)
+			clean_dcache_guest_page(vcpu, pfn, PAGE_SIZE);
 
 		if (exec_fault) {
 			new_pte = kvm_s2pte_mkexec(new_pte);