[PATCH 06/10] KVM: arm/arm64: Only clean the dcache on translation fault

Marc Zyngier
2017-10-09T15:20:32Z

The only case where we actually need to perform a dache 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).

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

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 1d47da22f75c..1911fadde88b 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);
}
- coherent_dcache_guest_page(vcpu, pfn, PMD_SIZE);
+
+ if (fault_status != FSC_PERM)
+ coherent_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);
}
- coherent_dcache_guest_page(vcpu, pfn, PAGE_SIZE);
+
+ if (fault_status != FSC_PERM)
+ coherent_dcache_guest_page(vcpu, pfn, PAGE_SIZE);

if (exec_fault) {
new_pte = kvm_s2pte_mkexec(new_pte);
--
2.14.1