user_mem_abort always creates a brand new PTE, even when handling
a permission fault. This is semantically wrong, as such a fault
should be handled by reading the existing entry and modifying it.
Convert user_mem_abort to stage2_get_pte()/stage2_set_pte_at(),
gicing the opportunity to test the present bit, and only use the
default PTE if nothing was present yet.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm/kvm/mmu.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 8fde75b..d033344 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -519,7 +519,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
gfn_t gfn, struct kvm_memory_slot *memslot,
unsigned long fault_status)
{
- pte_t new_pte;
+ pte_t new_pte, *ptep;
pfn_t pfn;
int ret;
bool write_fault, writable;
@@ -553,17 +553,24 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
if (is_error_pfn(pfn))
return -EFAULT;
- new_pte = pfn_pte(pfn, PAGE_S2);
coherent_icache_guest_page(vcpu->kvm, gfn);
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
+
+ ptep = stage2_get_pte(vcpu->kvm, memcache, fault_ipa);
+ if (pte_present(*ptep))
+ new_pte = *ptep;
+ else
+ new_pte = pfn_pte(pfn, PAGE_S2);
+
if (writable) {
kvm_set_s2pte_writable(&new_pte);
kvm_set_pfn_dirty(pfn);
}
- stage2_set_pte(vcpu->kvm, memcache, fault_ipa, &new_pte);
+
+ stage2_set_pte_at(vcpu->kvm, fault_ipa, ptep, new_pte);
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
--
1.8.1.2
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
