[PATCH v3 12/19] KVM: MMU: abstract some functions to handle fault pfn

[Xiao Guangrong]

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 <xiaoguangr...@cn.fujitsu.com>
---
 arch/x86/kvm/mmu.c         |   47 ++++++++++++++++++++++++++++++++-----------
 arch/x86/kvm/paging_tmpl.h |   12 +++++-----
 2 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 96a7ed4..9577013 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_mmio_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_mmio_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 58a29d0..870be69 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -373,7 +373,7 @@ 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;
        }
@@ -451,7 +451,7 @@ 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;
                }
@@ -621,10 +621,10 @@ 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;
-- 
1.7.5.4

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