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>

1 files changed, 7 insertions, 14 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 02c839f40e29..d1986b7dcec7 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -217,11 +217,6 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 
-static bool is_write_protection(struct kvm_vcpu *vcpu)
-{
-        return kvm_read_cr0_bits(vcpu, X86_CR0_WP);
-}
-
 static int is_cpuid_PSE36(void)
 {
         return 1;
@@ -243,11 +238,6 @@ static int is_large_pte(u64 pte)
         return pte & PT_PAGE_SIZE_MASK;
 }
 
-static int is_writable_pte(unsigned long pte)
-{
-        return pte & PT_WRITABLE_MASK;
-}
-
 static int is_dirty_gpte(unsigned long pte)
 {
         return pte & PT_DIRTY_MASK;
@@ -2247,15 +2237,17 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
         send_sig_info(SIGBUS, &info, tsk);
 }
 
-static int kvm_handle_bad_page(struct kvm *kvm, gfn_t gfn, pfn_t pfn)
+static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gva_t gva,
+                               unsigned access, gfn_t gfn, pfn_t pfn)
 {
         kvm_release_pfn_clean(pfn);
         if (is_hwpoison_pfn(pfn)) {
-                kvm_send_hwpoison_signal(gfn_to_hva(kvm, gfn), current);
+                kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
                 return 0;
         } else if (is_fault_pfn(pfn))
                 return -EFAULT;
 
+        vcpu_cache_mmio_info(vcpu, gva, gfn, access);
         return 1;
 }
 
@@ -2337,7 +2329,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn,
 
         /* mmio */
         if (is_error_pfn(pfn))
-                return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
+                return kvm_handle_bad_page(vcpu, v, ACC_ALL, gfn, pfn);
 
         spin_lock(&vcpu->kvm->mmu_lock);
         if (mmu_notifier_retry(vcpu, mmu_seq))
@@ -2564,6 +2556,7 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu)
         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
                 return;
 
+        vcpu_clear_mmio_info(vcpu, ~0ul);
         trace_kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
         if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
                 hpa_t root = vcpu->arch.mmu.root_hpa;
@@ -2710,7 +2703,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
 
         /* mmio */
         if (is_error_pfn(pfn))
-                return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
+                return kvm_handle_bad_page(vcpu, 0, 0, gfn, pfn);
         spin_lock(&vcpu->kvm->mmu_lock);
         if (mmu_notifier_retry(vcpu, mmu_seq))
                 goto out_unlock;