ati: use vga_read_byte in ati_cursor_define

This makes sure reads are confined to vga video memory.

v3: use uint32_t, fix cut+paste bug.
v2: fix ati_cursor_draw_line too.

Reported-by: xu hang <flier_m@outlook.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190917111441.27405-3-kraxel@redhat.com

hw/display/ati.c

@@ -19,6 +19,7 @@
 #include "qemu/osdep.h"
 #include "ati_int.h"
 #include "ati_regs.h"
+#include "vga-access.h"
 #include "hw/qdev-properties.h"
 #include "vga_regs.h"
 #include "qemu/log.h"
@@ -135,19 +136,19 @@ static void ati_vga_switch_mode(ATIVGAState *s)
 static void ati_cursor_define(ATIVGAState *s)
 {
     uint8_t data[1024];
-    uint8_t *src;
+    uint32_t srcoff;
     int i, j, idx = 0;
 
     if ((s->regs.cur_offset & BIT(31)) || s->cursor_guest_mode) {
         return; /* Do not update cursor if locked or rendered by guest */
     }
     /* FIXME handle cur_hv_offs correctly */
-    src = s->vga.vram_ptr + s->regs.cur_offset -
-          (s->regs.cur_hv_offs >> 16) - (s->regs.cur_hv_offs & 0xffff) * 16;
+    srcoff = s->regs.cur_offset -
+        (s->regs.cur_hv_offs >> 16) - (s->regs.cur_hv_offs & 0xffff) * 16;
     for (i = 0; i < 64; i++) {
         for (j = 0; j < 8; j++, idx++) {
-            data[idx] = src[i * 16 + j];
-            data[512 + idx] = src[i * 16 + j + 8];
+            data[idx] = vga_read_byte(&s->vga, srcoff + i * 16 + j);
+            data[512 + idx] = vga_read_byte(&s->vga, srcoff + i * 16 + j + 8);
         }
     }
     if (!s->cursor) {
@@ -189,7 +190,7 @@ static void ati_cursor_invalidate(VGACommonState *vga)
 static void ati_cursor_draw_line(VGACommonState *vga, uint8_t *d, int scr_y)
 {
     ATIVGAState *s = container_of(vga, ATIVGAState, vga);
-    uint8_t *src;
+    uint32_t srcoff;
     uint32_t *dp = (uint32_t *)d;
     int i, j, h;
 
@@ -199,13 +200,13 @@ static void ati_cursor_draw_line(VGACommonState *vga, uint8_t *d, int scr_y)
         return;
     }
     /* FIXME handle cur_hv_offs correctly */
-    src = s->vga.vram_ptr + s->cursor_offset + (scr_y - vga->hw_cursor_y) * 16;
+    srcoff = s->cursor_offset + (scr_y - vga->hw_cursor_y) * 16;
     dp = &dp[vga->hw_cursor_x];
     h = ((s->regs.crtc_h_total_disp >> 16) + 1) * 8;
     for (i = 0; i < 8; i++) {
         uint32_t color;
-        uint8_t abits = src[i];
-        uint8_t xbits = src[i + 8];
+        uint8_t abits = vga_read_byte(vga, srcoff + i);
+        uint8_t xbits = vga_read_byte(vga, srcoff + i + 8);
         for (j = 0; j < 8; j++, abits <<= 1, xbits <<= 1) {
             if (abits & BIT(7)) {
                 if (xbits & BIT(7)) {