4 files changed, 34 insertions, 19 deletions

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 99f55cb..265d77d 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -4381,9 +4381,12 @@ pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
 	m->md.pat_mode = ma;
 
 	/*
-	 * Update the direct mapping and flush the cache.
+	 * If "m" is a normal page, update its direct mapping.  This update
+	 * can be relied upon to perform any cache operations that are
+	 * required for data coherence.
 	 */
-	if (pmap_change_attr(PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)), PAGE_SIZE,
+	if ((m->flags & PG_FICTITIOUS) == 0 &&
+	    pmap_change_attr(PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)), PAGE_SIZE,
 	    m->md.pat_mode))
 		panic("memory attribute change on the direct map failed");
 }
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index 6103fd5..b973d0d 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -4466,12 +4466,13 @@ pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
 	m->md.pat_mode = ma;
 
 	/*
-	 * Flush CPU caches to make sure any data isn't cached that shouldn't
-	 * be, etc.
+	 * If "m" is a normal page, flush it from the cache.
 	 */    
-	/* If "Self Snoop" is supported, do nothing. */
-	if (!(cpu_feature & CPUID_SS))
-		pmap_invalidate_cache();
+	if ((m->flags & PG_FICTITIOUS) == 0) {
+		/* If "Self Snoop" is supported, do nothing. */
+		if (!(cpu_feature & CPUID_SS))
+			pmap_invalidate_cache();
+	}
 }
 
 int
diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index 9a9a1b4..051685a 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -3921,6 +3921,25 @@ pmap_unmapdev(vm_offset_t va, vm_size_t size)
 	kmem_free(kernel_map, base, size);
 }
 
+/*
+ * Sets the memory attribute for the specified page.
+ */
+void
+pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
+{
+
+	m->md.pat_mode = ma;
+
+	/*
+	 * If "m" is a normal page, flush it from the cache.
+	 */    
+	if ((m->flags & PG_FICTITIOUS) == 0) {
+		/* If "Self Snoop" is supported, do nothing. */
+		if (!(cpu_feature & CPUID_SS))
+			pmap_invalidate_cache();
+	}
+}
+
 int
 pmap_change_attr(va, size, mode)
 	vm_offset_t va;
diff --git a/sys/vm/device_pager.c b/sys/vm/device_pager.c
index 7993405..0d762de 100644
--- a/sys/vm/device_pager.c
+++ b/sys/vm/device_pager.c
@@ -305,7 +305,8 @@ dev_pager_haspage(object, pindex, before, after)
 
 /*
  * Create a fictitious page with the specified physical address and memory
- * attribute.
+ * attribute.  The memory attribute is the only the machine-dependent aspect
+ * of a fictitious page that must be initialized.
  */
 static vm_page_t
 dev_pager_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
@@ -317,11 +318,9 @@ dev_pager_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
 	/* Fictitious pages don't use "segind". */
 	m->flags = PG_FICTITIOUS;
 	/* Fictitious pages don't use "order" or "pool". */
-	pmap_page_init(m);
 	m->oflags = VPO_BUSY;
 	m->wire_count = 1;
-	if (memattr != VM_MEMATTR_DEFAULT)
-		pmap_page_set_memattr(m, memattr);
+	pmap_page_set_memattr(m, memattr);
 	return (m);
 }
 
@@ -334,9 +333,6 @@ dev_pager_putfake(vm_page_t m)
 
 	if (!(m->flags & PG_FICTITIOUS))
 		panic("dev_pager_putfake: bad page");
-	/* Restore the default memory attribute to "phys_addr". */
-	if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
-		pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
 	uma_zfree(fakepg_zone, m);
 }
 
@@ -350,10 +346,6 @@ dev_pager_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
 
 	if (!(m->flags & PG_FICTITIOUS))
 		panic("dev_pager_updatefake: bad page");
-	/* Restore the default memory attribute before changing "phys_addr". */
-	if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
-		pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
 	m->phys_addr = paddr;
-	if (memattr != VM_MEMATTR_DEFAULT)
-		pmap_page_set_memattr(m, memattr);
+	pmap_page_set_memattr(m, memattr);
 }