KVM: MMU: abstract some functions to handle fault pfn

Introduce handle_abnormal_pfn to handle fault pfn on page fault path,
introduce mmu_invalid_pfn to handle fault pfn on prefetch path

It is the preparing work for mmio page fault support

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 41 insertions, 18 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 96a7ed4e6837..1d4a2d9cc718 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2221,18 +2221,15 @@ 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_vcpu *vcpu, gva_t gva,
-                               unsigned access, gfn_t gfn, pfn_t pfn)
+static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
 {
         kvm_release_pfn_clean(pfn);
         if (is_hwpoison_pfn(pfn)) {
                 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;
+        return -EFAULT;
 }
 
 static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
@@ -2277,6 +2274,33 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
         }
 }
 
+static bool mmu_invalid_pfn(pfn_t pfn)
+{
+        return unlikely(is_invalid_pfn(pfn) || is_noslot_pfn(pfn));
+}
+
+static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
+                                pfn_t pfn, unsigned access, int *ret_val)
+{
+        bool ret = true;
+
+        /* The pfn is invalid, report the error! */
+        if (unlikely(is_invalid_pfn(pfn))) {
+                *ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
+                goto exit;
+        }
+
+        if (unlikely(is_noslot_pfn(pfn))) {
+                vcpu_cache_mmio_info(vcpu, gva, gfn, access);
+                *ret_val = 1;
+                goto exit;
+        }
+
+        ret = false;
+exit:
+        return ret;
+}
+
 static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
                          gva_t gva, pfn_t *pfn, bool write, bool *writable);
 
@@ -2311,9 +2335,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn,
         if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
                 return 0;
 
-        /* mmio */
-        if (is_error_pfn(pfn))
-                return kvm_handle_bad_page(vcpu, v, ACC_ALL, gfn, pfn);
+        if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
+                return r;
 
         spin_lock(&vcpu->kvm->mmu_lock);
         if (mmu_notifier_retry(vcpu, mmu_seq))
@@ -2685,9 +2708,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
         if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
                 return 0;
 
-        /* mmio */
-        if (is_error_pfn(pfn))
-                return kvm_handle_bad_page(vcpu, 0, 0, gfn, pfn);
+        if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
+                return r;
+
         spin_lock(&vcpu->kvm->mmu_lock);
         if (mmu_notifier_retry(vcpu, mmu_seq))
                 goto out_unlock;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index a4565df501cd..67998d3be084 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -367,7 +367,7 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
         pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
         pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte, true);
         pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
-        if (is_error_pfn(pfn)) {
+        if (mmu_invalid_pfn(pfn)) {
                 kvm_release_pfn_clean(pfn);
                 return;
         }
@@ -445,7 +445,7 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
                 gfn = gpte_to_gfn(gpte);
                 pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
                                       pte_access & ACC_WRITE_MASK);
-                if (is_error_pfn(pfn)) {
+                if (mmu_invalid_pfn(pfn)) {
                         kvm_release_pfn_clean(pfn);
                         break;
                 }
@@ -615,10 +615,10 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
                          &map_writable))
                 return 0;
 
-        /* mmio */
-        if (is_error_pfn(pfn))
-                return kvm_handle_bad_page(vcpu, mmu_is_nested(vcpu) ? 0 :
-                                      addr, walker.pte_access, walker.gfn, pfn);
+        if (handle_abnormal_pfn(vcpu, mmu_is_nested(vcpu) ? 0 : addr,
+                                walker.gfn, pfn, walker.pte_access, &r))
+                return r;
+
         spin_lock(&vcpu->kvm->mmu_lock);
         if (mmu_notifier_retry(vcpu, mmu_seq))
                 goto out_unlock;