KVM: do not release the error pfn

After commit a2766325cf9f9, the error pfn is replaced by the
error code, it need not be released anymore

[ The patch has been compiling tested for powerpc ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

6 files changed, 14 insertions, 21 deletions

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index c8f6c5826742..09ce5ac128f8 100644
--- a/arch/powerpc/kvm/e500_tlb.c
+++ b/arch/powerpc/kvm/e500_tlb.c
@@ -524,7 +524,6 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
                 if (is_error_pfn(pfn)) {
                         printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
                                         (long)gfn);
-                        kvm_release_pfn_clean(pfn);
                         return;
                 }
 
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d3cdf69da513..9651c2cd0005 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2496,7 +2496,9 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
                                 rmap_recycle(vcpu, sptep, gfn);
                 }
         }
-        kvm_release_pfn_clean(pfn);
+
+        if (!is_error_pfn(pfn))
+                kvm_release_pfn_clean(pfn);
 }
 
 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
@@ -2648,7 +2650,6 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
 
 static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
 {
-        kvm_release_pfn_clean(pfn);
         if (pfn == KVM_PFN_ERR_HWPOISON) {
                 kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
                 return 0;
@@ -3273,8 +3274,6 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
         if (!async)
                 return false; /* *pfn has correct page already */
 
-        kvm_release_pfn_clean(*pfn);
-
         if (!prefault && can_do_async_pf(vcpu)) {
                 trace_kvm_try_async_get_page(gva, gfn);
                 if (kvm_find_async_pf_gfn(vcpu, gfn)) {
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index ca403f9bb0f2..daff69e21150 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -116,10 +116,8 @@ static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
         gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
         pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
 
-        if (is_error_pfn(pfn)) {
-                kvm_release_pfn_clean(pfn);
+        if (is_error_pfn(pfn))
                 return;
-        }
 
         hpa =  pfn << PAGE_SHIFT;
         if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index bb7cf01cae76..bf8c42bf50fe 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -370,10 +370,8 @@ 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 (mmu_invalid_pfn(pfn)) {
-                kvm_release_pfn_clean(pfn);
+        if (mmu_invalid_pfn(pfn))
                 return;
-        }
 
         /*
          * we call mmu_set_spte() with host_writable = true because that
@@ -448,10 +446,8 @@ 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 (mmu_invalid_pfn(pfn)) {
-                        kvm_release_pfn_clean(pfn);
+                if (mmu_invalid_pfn(pfn))
                         break;
-                }
 
                 mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
                              NULL, PT_PAGE_TABLE_LEVEL, gfn,
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 6a67bea4019c..037cb6730e68 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -107,7 +107,6 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
                  */
                 pfn = kvm_pin_pages(slot, gfn, page_size);
                 if (is_error_pfn(pfn)) {
-                        kvm_release_pfn_clean(pfn);
                         gfn += 1;
                         continue;
                 }
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 93d3c6e063c8..eafba99d1070 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -102,9 +102,6 @@ static bool largepages_enabled = true;
 
 bool kvm_is_mmio_pfn(pfn_t pfn)
 {
-        if (is_error_pfn(pfn))
-                return false;
-
         if (pfn_valid(pfn)) {
                 int reserved;
                 struct page *tail = pfn_to_page(pfn);
@@ -1165,10 +1162,13 @@ EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
 
 static struct page *kvm_pfn_to_page(pfn_t pfn)
 {
-        WARN_ON(kvm_is_mmio_pfn(pfn));
+        if (is_error_pfn(pfn))
+                return KVM_ERR_PTR_BAD_PAGE;
 
-        if (is_error_pfn(pfn) || kvm_is_mmio_pfn(pfn))
+        if (kvm_is_mmio_pfn(pfn)) {
+                WARN_ON(1);
                 return KVM_ERR_PTR_BAD_PAGE;
+        }
 
         return pfn_to_page(pfn);
 }
@@ -1193,7 +1193,9 @@ EXPORT_SYMBOL_GPL(kvm_release_page_clean);
 
 void kvm_release_pfn_clean(pfn_t pfn)
 {
-        if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn))
+        WARN_ON(is_error_pfn(pfn));
+
+        if (!kvm_is_mmio_pfn(pfn))
                 put_page(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);