KVM: MMU: cache mmio info on page fault path
If the page fault is caused by mmio, we can cache the mmio info, later, we do
not need to walk guest page table and quickly know it is a mmio fault while we
emulate the mmio instruction
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 1e1c244..f0fb1a4 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -208,11 +208,8 @@
goto error;
}
- if (unlikely(write_fault && !is_writable_pte(pte)
- && (user_fault || is_write_protection(vcpu))))
- eperm = true;
-
- if (unlikely(user_fault && !(pte & PT_USER_MASK)))
+ if (!check_write_user_access(vcpu, write_fault, user_fault,
+ pte))
eperm = true;
#if PTTYPE == 64
@@ -625,8 +622,16 @@
return 0;
/* mmio */
- if (is_error_pfn(pfn))
- return kvm_handle_bad_page(vcpu->kvm, walker.gfn, pfn);
+ if (is_error_pfn(pfn)) {
+ unsigned access = walker.pte_access;
+ bool dirty = is_dirty_gpte(walker.ptes[walker.level - 1]);
+
+ if (!dirty)
+ access &= ~ACC_WRITE_MASK;
+
+ return kvm_handle_bad_page(vcpu, mmu_is_nested(vcpu) ? 0 :
+ addr, access, walker.gfn, pfn);
+ }
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
@@ -666,6 +671,8 @@
u64 *sptep;
int need_flush = 0;
+ vcpu_clear_mmio_info(vcpu, gva);
+
spin_lock(&vcpu->kvm->mmu_lock);
for_each_shadow_entry(vcpu, gva, iterator) {