From d634c883ca07c28da2cb84c019659694f05d8b3a Mon Sep 17 00:00:00 2001
From: BALATON Zoltan <balaton@eik.bme.hu>
Date: Sun, 21 Jun 2020 13:12:38 +0200
Subject: [PATCH] ati-vga: Support unaligned access to hardware cursor
 registers

This fixes horizontal mouse movement and pointer color with MacOS that
writes these registers with access size less than 4 so previously only
the last portion of access was effective overwriting previous partial
writes.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Message-id: ba1d5ba97f246e8807f86f1243c2bdc6497dc8f2.1592737958.git.balaton@eik.bme.hu
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/ati.c | 85 ++++++++++++++++++++++++++++++++----------------
 1 file changed, 57 insertions(+), 28 deletions(-)

diff --git a/hw/display/ati.c b/hw/display/ati.c
index 7216f7e08f..245130d52f 100644
--- a/hw/display/ati.c
+++ b/hw/display/ati.c
@@ -389,22 +389,28 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr, unsigned int size)
     case 0xf00 ... 0xfff:
         val = pci_default_read_config(&s->dev, addr - 0xf00, size);
         break;
-    case CUR_OFFSET:
-        val = s->regs.cur_offset;
+    case CUR_OFFSET ... CUR_OFFSET + 3:
+        val = ati_reg_read_offs(s->regs.cur_offset, addr - CUR_OFFSET, size);
         break;
-    case CUR_HORZ_VERT_POSN:
-        val = s->regs.cur_hv_pos;
-        val |= s->regs.cur_offset & BIT(31);
+    case CUR_HORZ_VERT_POSN ... CUR_HORZ_VERT_POSN + 3:
+        val = ati_reg_read_offs(s->regs.cur_hv_pos,
+                                addr - CUR_HORZ_VERT_POSN, size);
+        if (addr + size > CUR_HORZ_VERT_POSN + 3) {
+            val |= (s->regs.cur_offset & BIT(31)) >> (4 - size);
+        }
         break;
-    case CUR_HORZ_VERT_OFF:
-        val = s->regs.cur_hv_offs;
-        val |= s->regs.cur_offset & BIT(31);
+    case CUR_HORZ_VERT_OFF ... CUR_HORZ_VERT_OFF + 3:
+        val = ati_reg_read_offs(s->regs.cur_hv_offs,
+                                addr - CUR_HORZ_VERT_OFF, size);
+        if (addr + size > CUR_HORZ_VERT_OFF + 3) {
+            val |= (s->regs.cur_offset & BIT(31)) >> (4 - size);
+        }
         break;
-    case CUR_CLR0:
-        val = s->regs.cur_color0;
+    case CUR_CLR0 ... CUR_CLR0 + 3:
+        val = ati_reg_read_offs(s->regs.cur_color0, addr - CUR_CLR0, size);
         break;
-    case CUR_CLR1:
-        val = s->regs.cur_color1;
+    case CUR_CLR1 ... CUR_CLR1 + 3:
+        val = ati_reg_read_offs(s->regs.cur_color1, addr - CUR_CLR1, size);
         break;
     case DST_OFFSET:
         val = s->regs.dst_offset;
@@ -679,48 +685,71 @@ static void ati_mm_write(void *opaque, hwaddr addr,
     case 0xf00 ... 0xfff:
         /* read-only copy of PCI config space so ignore writes */
         break;
-    case CUR_OFFSET:
-        if (s->regs.cur_offset != (data & 0x87fffff0)) {
-            s->regs.cur_offset = data & 0x87fffff0;
+    case CUR_OFFSET ... CUR_OFFSET + 3:
+    {
+        uint32_t t = s->regs.cur_offset;
+
+        ati_reg_write_offs(&t, addr - CUR_OFFSET, data, size);
+        t &= 0x87fffff0;
+        if (s->regs.cur_offset != t) {
+            s->regs.cur_offset = t;
             ati_cursor_define(s);
         }
         break;
-    case CUR_HORZ_VERT_POSN:
-        s->regs.cur_hv_pos = data & 0x3fff0fff;
-        if (data & BIT(31)) {
-            s->regs.cur_offset |= data & BIT(31);
+    }
+    case CUR_HORZ_VERT_POSN ... CUR_HORZ_VERT_POSN + 3:
+    {
+        uint32_t t = s->regs.cur_hv_pos | (s->regs.cur_offset & BIT(31));
+
+        ati_reg_write_offs(&t, addr - CUR_HORZ_VERT_POSN, data, size);
+        s->regs.cur_hv_pos = t & 0x3fff0fff;
+        if (t & BIT(31)) {
+            s->regs.cur_offset |= t & BIT(31);
         } else if (s->regs.cur_offset & BIT(31)) {
             s->regs.cur_offset &= ~BIT(31);
             ati_cursor_define(s);
         }
         if (!s->cursor_guest_mode &&
-            (s->regs.crtc_gen_cntl & CRTC2_CUR_EN) && !(data & BIT(31))) {
+            (s->regs.crtc_gen_cntl & CRTC2_CUR_EN) && !(t & BIT(31))) {
             dpy_mouse_set(s->vga.con, s->regs.cur_hv_pos >> 16,
                           s->regs.cur_hv_pos & 0xffff, 1);
         }
         break;
+    }
     case CUR_HORZ_VERT_OFF:
-        s->regs.cur_hv_offs = data & 0x3f003f;
-        if (data & BIT(31)) {
-            s->regs.cur_offset |= data & BIT(31);
+    {
+        uint32_t t = s->regs.cur_hv_offs | (s->regs.cur_offset & BIT(31));
+
+        ati_reg_write_offs(&t, addr - CUR_HORZ_VERT_OFF, data, size);
+        s->regs.cur_hv_offs = t & 0x3f003f;
+        if (t & BIT(31)) {
+            s->regs.cur_offset |= t & BIT(31);
         } else if (s->regs.cur_offset & BIT(31)) {
             s->regs.cur_offset &= ~BIT(31);
             ati_cursor_define(s);
         }
         break;
-    case CUR_CLR0:
-        if (s->regs.cur_color0 != (data & 0xffffff)) {
-            s->regs.cur_color0 = data & 0xffffff;
+    }
+    case CUR_CLR0 ... CUR_CLR0 + 3:
+    {
+        uint32_t t = s->regs.cur_color0;
+
+        ati_reg_write_offs(&t, addr - CUR_CLR0, data, size);
+        t &= 0xffffff;
+        if (s->regs.cur_color0 != t) {
+            s->regs.cur_color0 = t;
             ati_cursor_define(s);
         }
         break;
-    case CUR_CLR1:
+    }
+    case CUR_CLR1 ... CUR_CLR1 + 3:
         /*
          * Update cursor unconditionally here because some clients set up
          * other registers before actually writing cursor data to memory at
          * offset so we would miss cursor change unless always updating here
          */
-        s->regs.cur_color1 = data & 0xffffff;
+        ati_reg_write_offs(&s->regs.cur_color1, addr - CUR_CLR1, data, size);
+        s->regs.cur_color1 &= 0xffffff;
         ati_cursor_define(s);
         break;
     case DST_OFFSET: