Re: [Qemu-devel] [PATCH v3 2/2] ati: use vga_read_byte in ati_cursor_define

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 9/17/19 1:14 PM, Gerd Hoffmann wrote:
> 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>
> ---
>  hw/display/ati.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/display/ati.c b/hw/display/ati.c
> index 8f940eee221a..db3b2543163f 100644
> --- a/hw/display/ati.c
> +++ b/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)) {
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>