video: fix handling framebuffer located above 4GB

On some machines (for example Thinkpad P52), UEFI GOP reports
framebuffer located above 4GB (0x4000000000 on that machine). This
address does not fit in {xen,dom0}_vga_console_info.u.vesa_lfb.lfb_base
field, which is 32bit. The overflow here cause all kind of memory
corruption when anything tries to write something on the screen,
starting with zeroing the whole framebuffer in vesa_init().

Fix this similar to how it's done in Linux: add ext_lfb_base field at
the end of the structure, to hold upper 32bits of the address. Since the
field is added at the end of the structure, it will work with older
Linux versions too (other than using possibly truncated address - no
worse than without this change). Thanks to ABI containing size of the
structure (start_info.console.dom0.info_size), Linux can detect when
this field is present and use it appropriately then.

Since this change public interface and use __XEN_INTERFACE_VERSION__,
bump __XEN_LATEST_INTERFACE_VERSION__.

Note: if/when backporting this change to Xen <= 4.12, #if in xen.h needs
to be extended with " || defined(__XEN__)".

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 9cf11fdcd91ff8e9cd038f8336cf21f0701e8b7b
master date: 2019-05-17 14:48:23 +0200

diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 5789d2cb70726a556785e823ee4eafcdb514aa6c..7a13a30bc077f1233cc00fcbe94b2fbc54238e8b 100644 (file)
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -550,6 +550,7 @@ static void __init efi_arch_video_init(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop,
         vga_console_info.u.vesa_lfb.bytes_per_line =
             (mode_info->PixelsPerScanLine * bpp + 7) >> 3;
         vga_console_info.u.vesa_lfb.lfb_base = gop->Mode->FrameBufferBase;
+        vga_console_info.u.vesa_lfb.ext_lfb_base = gop->Mode->FrameBufferBase >> 32;
         vga_console_info.u.vesa_lfb.lfb_size =
             (gop->Mode->FrameBufferSize + 0xffff) >> 16;
     }

diff --git a/xen/drivers/video/vesa.c b/xen/drivers/video/vesa.c
index c92497e0bc86dddfa3a893bb1a5a9cab63dbb609..bbff82b38fa735b5a0b3c9faed4552700469c6d1 100644 (file)
--- a/xen/drivers/video/vesa.c
+++ b/xen/drivers/video/vesa.c
@@ -40,6 +40,11 @@ static int __init parse_font_height(const char *s)
 }
 custom_param("font", parse_font_height);
 
+static inline paddr_t lfb_base(void)
+{
+    return ((paddr_t)vlfb_info.ext_lfb_base << 32) | vlfb_info.lfb_base;
+}
+
 void __init vesa_early_init(void)
 {
     unsigned int vram_vmode;
@@ -97,15 +102,14 @@ 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(vlfb_info.lfb_base, vram_remap);
+    lfbp.lfb = lfb = ioremap(lfb_base(), vram_remap);
     if ( !lfb )
         return;
 
     memset(lfb, 0, vram_remap);
 
-    printk(XENLOG_INFO "vesafb: framebuffer at %#x, mapped to 0x%p, "
-           "using %uk, total %uk\n",
-           vlfb_info.lfb_base, lfb,
+    printk(XENLOG_INFO "vesafb: framebuffer at 0x%" PRIpaddr ", mapped to 0x%p, using %uk, total %uk\n",
+           lfb_base(), lfb,
            vram_remap >> 10, vram_total >> 10);
     printk(XENLOG_INFO "vesafb: mode is %dx%dx%u, linelength=%d, font %ux%u\n",
            vlfb_info.width, vlfb_info.height,
@@ -167,7 +171,7 @@ void __init vesa_mtrr_init(void)
 
     /* Try and find a power of two to add */
     do {
-        rc = mtrr_add(vlfb_info.lfb_base, size_total, type, 1);
+        rc = mtrr_add(lfb_base(), size_total, type, 1);
         size_total >>= 1;
     } while ( (size_total >= PAGE_SIZE) && (rc == -EINVAL) );
 }

diff --git a/xen/include/public/xen-compat.h b/xen/include/public/xen-compat.h
index b67365340bf115d552b6df3807d8eef7fa36eca4..80c0ef2c3a9c8fd4627e512783ce548d2bcab46e 100644 (file)
--- a/xen/include/public/xen-compat.h
+++ b/xen/include/public/xen-compat.h
@@ -27,7 +27,7 @@
 #ifndef __XEN_PUBLIC_XEN_COMPAT_H__
 #define __XEN_PUBLIC_XEN_COMPAT_H__
 
-#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040900
+#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040901
 
 #if defined(__XEN__) || defined(__XEN_TOOLS__)
 /* Xen is built with matching headers and implements the latest interface. */

diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index fb1df8f293659921132ebb0b75cd78c793d9ffd1..6c180c45eba720e5c65b8746cd32e54560d47e42 100644 (file)
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -922,6 +922,12 @@ typedef struct dom0_vga_console_info {
             uint32_t gbl_caps;
             /* Mode attributes (offset 0x0, VESA command 0x4f01). */
             uint16_t mode_attrs;
+            uint16_t pad;
+#endif
+#if __XEN_INTERFACE_VERSION__ >= 0x00040901 && \
+    __XEN_INTERFACE_VERSION__ != 0x00040a00
+            /* high 32 bits of lfb_base */
+            uint32_t ext_lfb_base;
 #endif
         } vesa_lfb;
     } u;