3 files changed, 28 insertions, 5 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d8d48329cb82..89d7a2cae53b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2078,7 +2078,9 @@ static int kvm_handle_bad_page(struct kvm *kvm, gfn_t gfn, pfn_t pfn)
         if (is_hwpoison_pfn(pfn)) {
                 kvm_send_hwpoison_signal(kvm, gfn);
                 return 0;
-        }
+        } else if (is_fault_pfn(pfn))
+                return -EFAULT;
+
         return 1;
 }
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e796326f3646..8055067b6bec 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -269,6 +269,7 @@ extern pfn_t bad_pfn;
 int is_error_page(struct page *page);
 int is_error_pfn(pfn_t pfn);
 int is_hwpoison_pfn(pfn_t pfn);
+int is_fault_pfn(pfn_t pfn);
 int kvm_is_error_hva(unsigned long addr);
 int kvm_set_memory_region(struct kvm *kvm,
                           struct kvm_userspace_memory_region *mem,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 630d1224f187..b78b794c1039 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -96,6 +96,9 @@ static bool largepages_enabled = true;
 static struct page *hwpoison_page;
 static pfn_t hwpoison_pfn;
 
+static struct page *fault_page;
+static pfn_t fault_pfn;
+
 inline int kvm_is_mmio_pfn(pfn_t pfn)
 {
         if (pfn_valid(pfn)) {
@@ -815,13 +818,13 @@ EXPORT_SYMBOL_GPL(kvm_disable_largepages);
 
 int is_error_page(struct page *page)
 {
-        return page == bad_page || page == hwpoison_page;
+        return page == bad_page || page == hwpoison_page || page == fault_page;
 }
 EXPORT_SYMBOL_GPL(is_error_page);
 
 int is_error_pfn(pfn_t pfn)
 {
-        return pfn == bad_pfn || pfn == hwpoison_pfn;
+        return pfn == bad_pfn || pfn == hwpoison_pfn || pfn == fault_pfn;
 }
 EXPORT_SYMBOL_GPL(is_error_pfn);
 
@@ -831,6 +834,12 @@ int is_hwpoison_pfn(pfn_t pfn)
 }
 EXPORT_SYMBOL_GPL(is_hwpoison_pfn);
 
+int is_fault_pfn(pfn_t pfn)
+{
+        return pfn == fault_pfn;
+}
+EXPORT_SYMBOL_GPL(is_fault_pfn);
+
 static inline unsigned long bad_hva(void)
 {
         return PAGE_OFFSET;
@@ -959,8 +968,8 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr)
                 if (vma == NULL || addr < vma->vm_start ||
                     !(vma->vm_flags & VM_PFNMAP)) {
                         up_read(&current->mm->mmap_sem);
-                        get_page(bad_page);
-                        return page_to_pfn(bad_page);
+                        get_page(fault_page);
+                        return page_to_pfn(fault_page);
                 }
 
                 pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
@@ -2226,6 +2235,15 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 
         hwpoison_pfn = page_to_pfn(hwpoison_page);
 
+        fault_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+
+        if (fault_page == NULL) {
+                r = -ENOMEM;
+                goto out_free_0;
+        }
+
+        fault_pfn = page_to_pfn(fault_page);
+
         if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
                 r = -ENOMEM;
                 goto out_free_0;
@@ -2298,6 +2316,8 @@ out_free_1:
 out_free_0a:
         free_cpumask_var(cpus_hardware_enabled);
 out_free_0:
+        if (fault_page)
+                __free_page(fault_page);
         if (hwpoison_page)
                 __free_page(hwpoison_page);
         __free_page(bad_page);