--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -602,6 +602,8 @@ void destroy_perdomain_mapping(struct do
                                unsigned int nr);
 void free_perdomain_mappings(struct domain *);
 
+void __iomem *ioremap_wc(paddr_t, size_t);
+
 extern int memory_add(unsigned long spfn, unsigned long epfn, unsigned int pxm);
 
 void domain_set_alloc_bitsize(struct domain *d);
--- a/xen/arch/x86/include/asm/page.h
+++ b/xen/arch/x86/include/asm/page.h
@@ -349,8 +349,10 @@ void efi_update_l4_pgtable(unsigned int
 #define __PAGE_HYPERVISOR_RX      (_PAGE_PRESENT | _PAGE_ACCESSED)
 #define __PAGE_HYPERVISOR         (__PAGE_HYPERVISOR_RX | \
                                    _PAGE_DIRTY | _PAGE_RW)
+#define __PAGE_HYPERVISOR_WT      (__PAGE_HYPERVISOR | _PAGE_PWT)
 #define __PAGE_HYPERVISOR_UCMINUS (__PAGE_HYPERVISOR | _PAGE_PCD)
 #define __PAGE_HYPERVISOR_UC      (__PAGE_HYPERVISOR | _PAGE_PCD | _PAGE_PWT)
+#define __PAGE_HYPERVISOR_WC      (__PAGE_HYPERVISOR | _PAGE_PAT)
 #define __PAGE_HYPERVISOR_SHSTK   (__PAGE_HYPERVISOR_RO | _PAGE_DIRTY)
 
 #define MAP_SMALL_PAGES _PAGE_AVAIL0 /* don't use superpages mappings */
--- a/xen/arch/x86/include/asm/x86_64/page.h
+++ b/xen/arch/x86/include/asm/x86_64/page.h
@@ -152,6 +152,10 @@ static inline intpte_t put_pte_flags(uns
                                  _PAGE_GLOBAL | _PAGE_NX)
 #define PAGE_HYPERVISOR_UC      (__PAGE_HYPERVISOR_UC | \
                                  _PAGE_GLOBAL | _PAGE_NX)
+#define PAGE_HYPERVISOR_WC      (__PAGE_HYPERVISOR_WC | \
+                                 _PAGE_GLOBAL | _PAGE_NX)
+#define PAGE_HYPERVISOR_WT      (__PAGE_HYPERVISOR_WT | \
+                                 _PAGE_GLOBAL | _PAGE_NX)
 
 #endif /* __X86_64_PAGE_H__ */
 
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5895,6 +5895,20 @@ void __iomem *ioremap(paddr_t pa, size_t
     return (void __force __iomem *)va;
 }
 
+void __iomem *__init ioremap_wc(paddr_t pa, size_t len)
+{
+    mfn_t mfn = _mfn(PFN_DOWN(pa));
+    unsigned int offs = pa & (PAGE_SIZE - 1);
+    unsigned int nr = PFN_UP(offs + len);
+    void *va;
+
+    WARN_ON(page_is_ram_type(mfn_x(mfn), RAM_TYPE_CONVENTIONAL));
+
+    va = __vmap(&mfn, nr, 1, 1, PAGE_HYPERVISOR_WC, VMAP_DEFAULT);
+
+    return (void __force __iomem *)(va + offs);
+}
+
 int create_perdomain_mapping(struct domain *d, unsigned long va,
                              unsigned int nr, l1_pgentry_t **pl1tab,
                              struct page_info **ppg)
--- a/xen/drivers/video/vesa.c
+++ b/xen/drivers/video/vesa.c
@@ -9,9 +9,9 @@
 #include <xen/param.h>
 #include <xen/xmalloc.h>
 #include <xen/kernel.h>
+#include <xen/mm.h>
 #include <xen/vga.h>
 #include <asm/io.h>
-#include <asm/page.h>
 #include "font.h"
 #include "lfb.h"
 
@@ -103,7 +103,7 @@ void __init vesa_init(void)
     lfbp.text_columns = vlfb_info.width / font->width;
     lfbp.text_rows = vlfb_info.height / font->height;
 
-    lfbp.lfb = lfb = ioremap(lfb_base(), vram_remap);
+    lfbp.lfb = lfb = ioremap_wc(lfb_base(), vram_remap);
     if ( !lfb )
         return;
 
@@ -179,8 +179,7 @@ void __init vesa_mtrr_init(void)
 
 static void lfb_flush(void)
 {
-    if ( vesa_mtrr == 3 )
-        __asm__ __volatile__ ("sfence" : : : "memory");
+    __asm__ __volatile__ ("sfence" : : : "memory");
 }
 
 void __init vesa_endboot(bool_t keep)
--- a/xen/drivers/video/vga.c
+++ b/xen/drivers/video/vga.c
@@ -79,7 +79,7 @@ void __init video_init(void)
     {
     case XEN_VGATYPE_TEXT_MODE_3:
         if ( page_is_ram_type(paddr_to_pfn(0xB8000), RAM_TYPE_CONVENTIONAL) ||
-             ((video = ioremap(0xB8000, 0x8000)) == NULL) )
+             ((video = ioremap_wc(0xB8000, 0x8000)) == NULL) )
             return;
         outw(0x200a, 0x3d4); /* disable cursor */
         columns = vga_console_info.u.text_mode_3.columns;
@@ -164,7 +164,11 @@ void __init video_endboot(void)
     {
     case XEN_VGATYPE_TEXT_MODE_3:
         if ( !vgacon_keep )
+        {
             memset(video, 0, columns * lines * 2);
+            iounmap(video);
+            video = ZERO_BLOCK_PTR;
+        }
         break;
     case XEN_VGATYPE_VESA_LFB:
     case XEN_VGATYPE_EFI_LFB:
