3 files changed, 28 insertions, 7 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 24c23c66b226..bf82b1f2e834 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3306,7 +3306,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
          * here.
          */
         if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn) &&
-            level == PT_PAGE_TABLE_LEVEL &&
+            !kvm_is_zone_device_pfn(pfn) && level == PT_PAGE_TABLE_LEVEL &&
             PageTransCompoundMap(pfn_to_page(pfn)) &&
             !mmu_gfn_lpage_is_disallowed(vcpu, gfn, PT_DIRECTORY_LEVEL)) {
                 unsigned long mask;
@@ -5914,9 +5914,9 @@ restart:
                  * the guest, and the guest page table is using 4K page size
                  * mapping if the indirect sp has level = 1.
                  */
-                if (sp->role.direct &&
-                        !kvm_is_reserved_pfn(pfn) &&
-                        PageTransCompoundMap(pfn_to_page(pfn))) {
+                if (sp->role.direct && !kvm_is_reserved_pfn(pfn) &&
+                    !kvm_is_zone_device_pfn(pfn) &&
+                    PageTransCompoundMap(pfn_to_page(pfn))) {
                         pte_list_remove(rmap_head, sptep);
 
                         if (kvm_available_flush_tlb_with_range())
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 719fc3e15ea4..290dbe353a47 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -966,6 +966,7 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu);
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
 
 bool kvm_is_reserved_pfn(kvm_pfn_t pfn);
+bool kvm_is_zone_device_pfn(kvm_pfn_t pfn);
 
 struct kvm_irq_ack_notifier {
         struct hlist_node link;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e7a07132cd7f..0dac149ead16 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -149,10 +149,30 @@ __weak int kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
         return 0;
 }
 
+bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)
+{
+        /*
+         * The metadata used by is_zone_device_page() to determine whether or
+         * not a page is ZONE_DEVICE is guaranteed to be valid if and only if
+         * the device has been pinned, e.g. by get_user_pages().  WARN if the
+         * page_count() is zero to help detect bad usage of this helper.
+         */
+        if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))
+                return false;
+
+        return is_zone_device_page(pfn_to_page(pfn));
+}
+
 bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
 {
+        /*
+         * ZONE_DEVICE pages currently set PG_reserved, but from a refcounting
+         * perspective they are "normal" pages, albeit with slightly different
+         * usage rules.
+         */
         if (pfn_valid(pfn))
-                return PageReserved(pfn_to_page(pfn));
+                return PageReserved(pfn_to_page(pfn)) &&
+                       !kvm_is_zone_device_pfn(pfn);
 
         return true;
 }
@@ -1857,7 +1877,7 @@ EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
 
 void kvm_set_pfn_dirty(kvm_pfn_t pfn)
 {
-        if (!kvm_is_reserved_pfn(pfn)) {
+        if (!kvm_is_reserved_pfn(pfn) && !kvm_is_zone_device_pfn(pfn)) {
                 struct page *page = pfn_to_page(pfn);
 
                 SetPageDirty(page);
@@ -1867,7 +1887,7 @@ EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
 
 void kvm_set_pfn_accessed(kvm_pfn_t pfn)
 {
-        if (!kvm_is_reserved_pfn(pfn))
+        if (!kvm_is_reserved_pfn(pfn) && !kvm_is_zone_device_pfn(pfn))
                 mark_page_accessed(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);