[Xen-changelog] [xen staging-4.12] video: fix handling framebuffer located above 4GB

[patchbot@xxxxxxx]

commit 8b129ba3043e3daafb3ded33a2dc883bb505ffc0
Author:     Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon Sep 23 14:14:10 2019 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Sep 23 14:14:10 2019 +0200

    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@xxxxxxxxxxxxxxxxxxxxxx>
    Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    master commit: 9cf11fdcd91ff8e9cd038f8336cf21f0701e8b7b
    master date: 2019-05-17 14:48:23 +0200
---
 xen/arch/x86/efi/efi-boot.h     |  1 +
 xen/drivers/video/vesa.c        | 14 +++++++++-----
 xen/include/public/xen-compat.h |  2 +-
 xen/include/public/xen.h        |  5 +++++
 4 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 5789d2cb70..7a13a30bc0 100644
--- 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 c92497e0bc..bbff82b38f 100644
--- 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 6fabca1889..e4b4b59840 100644
--- 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__ 0x00040a00
+#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040a01
 
 #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 ccdffc0ad1..0d395404b0 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -922,6 +922,11 @@ 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__ >= 0x00040a01
+            /* high 32 bits of lfb_base */
+            uint32_t ext_lfb_base;
 #endif
         } vesa_lfb;
     } u;
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.12

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