KVM: do not release the error page

After commit a2766325, the error page is replaced by the
error code, it need not be released anymore

[ The patch has been compiling tested for powerpc ]
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/powerpc/kvm/44x_tlb.c

@@ -319,7 +319,6 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gpa_t gpaddr,
 	if (is_error_page(new_page)) {
 		printk(KERN_ERR "Couldn't get guest page for gfn %llx!\n",
 			(unsigned long long)gfn);
-		kvm_release_page_clean(new_page);
 		return;
 	}
 	hpaddr = page_to_phys(new_page);

arch/powerpc/kvm/book3s_pr.c

@@ -242,10 +242,8 @@ static void kvmppc_patch_dcbz(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
 	int i;
 
 	hpage = gfn_to_page(vcpu->kvm, pte->raddr >> PAGE_SHIFT);
-	if (is_error_page(hpage)) {
-		kvm_release_page_clean(hpage);
+	if (is_error_page(hpage))
 		return;
-	}
 
 	hpage_offset = pte->raddr & ~PAGE_MASK;
 	hpage_offset &= ~0xFFFULL;

arch/x86/kvm/svm.c

@@ -2105,7 +2105,6 @@ static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, struct page **_page)
 	return kmap(page);
 
 error:
-	kvm_release_page_clean(page);
 	kvm_inject_gp(&svm->vcpu, 0);
 
 	return NULL;

arch/x86/kvm/vmx.c

@@ -596,10 +596,9 @@ static inline struct vmcs12 *get_vmcs12(struct kvm_vcpu *vcpu)
 static struct page *nested_get_page(struct kvm_vcpu *vcpu, gpa_t addr)
 {
 	struct page *page = gfn_to_page(vcpu->kvm, addr >> PAGE_SHIFT);
-	if (is_error_page(page)) {
-		kvm_release_page_clean(page);
+	if (is_error_page(page))
 		return NULL;
-	}
+
 	return page;
 }
 

arch/x86/kvm/x86.c

@@ -1639,10 +1639,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 		vcpu->arch.time_page =
 				gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
 
-		if (is_error_page(vcpu->arch.time_page)) {
-			kvm_release_page_clean(vcpu->arch.time_page);
+		if (is_error_page(vcpu->arch.time_page))
 			vcpu->arch.time_page = NULL;
-		}
+
 		break;
 	}
 	case MSR_KVM_ASYNC_PF_EN:
@@ -3945,10 +3944,8 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
 		goto emul_write;
 
 	page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
-	if (is_error_page(page)) {
-		kvm_release_page_clean(page);
+	if (is_error_page(page))
 		goto emul_write;
-	}
 
 	kaddr = kmap_atomic(page);
 	kaddr += offset_in_page(gpa);

include/linux/kvm_host.h

@@ -457,7 +457,7 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
 pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
 		      bool *writable);
 pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn);
-void kvm_release_pfn_dirty(pfn_t);
+void kvm_release_pfn_dirty(pfn_t pfn);
 void kvm_release_pfn_clean(pfn_t pfn);
 void kvm_set_pfn_dirty(pfn_t pfn);
 void kvm_set_pfn_accessed(pfn_t pfn);

virt/kvm/async_pf.c

@@ -111,7 +111,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 			list_entry(vcpu->async_pf.done.next,
 				   typeof(*work), link);
 		list_del(&work->link);
-		if (work->page)
+		if (!is_error_page(work->page))
 			kvm_release_page_clean(work->page);
 		kmem_cache_free(async_pf_cache, work);
 	}
@@ -138,7 +138,7 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
 
 		list_del(&work->queue);
 		vcpu->async_pf.queued--;
-		if (work->page)
+		if (!is_error_page(work->page))
 			kvm_release_page_clean(work->page);
 		kmem_cache_free(async_pf_cache, work);
 	}

virt/kvm/kvm_main.c

@@ -1186,8 +1186,9 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
 
 void kvm_release_page_clean(struct page *page)
 {
-	if (!is_error_page(page))
-		kvm_release_pfn_clean(page_to_pfn(page));
+	WARN_ON(is_error_page(page));
+
+	kvm_release_pfn_clean(page_to_pfn(page));
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_clean);