File 0147-vga-add-vga_scanline_invalidated-he.patch of Package qemu-linux-user.10216

Overview Repositories Revisions Requests Users Attributes Meta

File 0147-vga-add-vga_scanline_invalidated-he.patch of Package qemu-linux-user.10216

From 903a2a44b7862c987c176995ba9f751ebeb77254 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 21 Apr 2017 11:16:26 +0200
Subject: [PATCH] vga: add vga_scanline_invalidated helper

Add vga_scanline_invalidated helper to check whenever a scanline was
invalidated.  Add a sanity check to fix OOB read access for display
heights larger than 2048.

Only cirrus uses this, for hardware cursor rendering, so having this
work properly for the first 2048 scanlines only shouldn't be a problem
as the cirrus can't handle large resolutions anyway.  Also changing the
invalidated_y_table size would break live migration.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20170421091632.30900-4-kraxel@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit f3289f6f0f9781d1fe77b4cfc3f18a6336eaed72)
[BR: Support for BSC#1084604 (and other useful vga fixes)]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/display/vga.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/hw/display/vga.c b/hw/display/vga.c
index 08f969d98a..e452e34849 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -1437,6 +1437,14 @@ void vga_invalidate_scanlines(VGACommonState *s, int y1, int y2)
     }
 }
 
+static bool vga_scanline_invalidated(VGACommonState *s, int y)
+{
+    if (y >= VGA_MAX_HEIGHT) {
+        return false;
+    }
+    return s->invalidated_y_table[y >> 5] & (1 << (y & 0x1f));
+}
+
 void vga_sync_dirty_bitmap(VGACommonState *s)
 {
     memory_region_sync_dirty_bitmap(&s->vram);
@@ -1641,8 +1649,8 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
         page1 = addr + bwidth - 1;
         update |= memory_region_get_dirty(&s->vram, page0, page1 - page0,
                                           DIRTY_MEMORY_VGA);
-        /* explicit invalidation for the hardware cursor */
-        update |= (s->invalidated_y_table[y >> 5] >> (y & 0x1f)) & 1;
+        /* explicit invalidation for the hardware cursor (cirrus only) */
+        update |= vga_scanline_invalidated(s, y);
         if (update) {
             if (y_start < 0)
                 y_start = y;
@@ -1689,7 +1697,7 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
                                   page_max - page_min,
                                   DIRTY_MEMORY_VGA);
     }
-    memset(s->invalidated_y_table, 0, ((height + 31) >> 5) * 4);
+    memset(s->invalidated_y_table, 0, sizeof(s->invalidated_y_table));
 }
 
 static void vga_draw_blank(VGACommonState *s, int full_update)

Places

File 0147-vga-add-vga_scanline_invalidated-he.patch of Package qemu-linux-user.10216

Places