[Qemu-devel] [PATCH 2/6] Make sure to enable dirty tracking of VBE vram mapping

[Dave Airlie <airlied@gmail.com>]

From: Anthony Liguori <aliguori@us.ibm.com>

Apparently, VBE maps the VGA vram to a fixed physical location.  KVM requires
that all mappings of the VGA vram have dirty tracking enabled on them.  Any
access to the VGA vram through the VBE mapping currently fails to result in
dirty page tracking updates causing a black screen.

This is the true root cause of VMware VGA not working correctly under KVM and
likely also an issue with some of the std-vga black screen issues too.

Cirrus does not enable VBE so it would not be a problem when using Cirrus.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Rebased-by: Dave Airlie <airlied@redhat.com>
---
 hw/vga-isa.c    |    6 +-----
 hw/vga-pci.c    |    7 +------
 hw/vga.c        |   24 ++++++++++++++++++++++++
 hw/vga_int.h    |    5 +++--
 hw/vmware_vga.c |    8 ++------
 5 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/hw/vga-isa.c b/hw/vga-isa.c
index 5f29904..7937144 100644
--- a/hw/vga-isa.c
+++ b/hw/vga-isa.c
@@ -42,11 +42,7 @@ int isa_vga_init(void)
     s->ds = graphic_console_init(s->update, s->invalidate,
                                  s->screen_dump, s->text_update, s);
 
-#ifdef CONFIG_BOCHS_VBE
-    /* XXX: use optimized standard vga accesses */
-    cpu_register_physical_memory(VBE_DISPI_LFB_PHYSICAL_ADDRESS,
-                                 VGA_RAM_SIZE, s->vram_offset);
-#endif
+    vga_init_vbe(s);
     /* ROM BIOS */
     rom_add_vga(VGABIOS_FILENAME);
     return 0;
diff --git a/hw/vga-pci.c b/hw/vga-pci.c
index e8cc024..eef78ed 100644
--- a/hw/vga-pci.c
+++ b/hw/vga-pci.c
@@ -106,12 +106,7 @@ static int pci_vga_initfn(PCIDevice *dev)
                          PCI_BASE_ADDRESS_MEM_PREFETCH, vga_map);
      }
 
-#ifdef CONFIG_BOCHS_VBE
-    /* XXX: use optimized standard vga accesses */
-    cpu_register_physical_memory(VBE_DISPI_LFB_PHYSICAL_ADDRESS,
-                                 VGA_RAM_SIZE, s->vram_offset);
-#endif
-
+    vga_init_vbe(s);
      /* ROM BIOS */
      rom_add_vga(VGABIOS_FILENAME);
      return 0;
diff --git a/hw/vga.c b/hw/vga.c
index 740fe28..5b0c55e 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -1581,6 +1581,14 @@ static void vga_sync_dirty_bitmap(VGACommonState *s)
         cpu_physical_sync_dirty_bitmap(isa_mem_base + 0xa0000, 0xa8000);
         cpu_physical_sync_dirty_bitmap(isa_mem_base + 0xa8000, 0xb0000);
     }
+
+#ifdef CONFIG_BOCHS_VBE
+    if (s->vbe_mapped) {
+        cpu_physical_sync_dirty_bitmap(VBE_DISPI_LFB_PHYSICAL_ADDRESS,
+                                       VBE_DISPI_LFB_PHYSICAL_ADDRESS + s->vram_size);
+    }
+#endif
+
 }
 
 void vga_dirty_log_start(VGACommonState *s)
@@ -1592,6 +1600,13 @@ void vga_dirty_log_start(VGACommonState *s)
         kvm_log_start(isa_mem_base + 0xa0000, 0x8000);
         kvm_log_start(isa_mem_base + 0xa8000, 0x8000);
     }
+
+#ifdef CONFIG_BOCHS_VBE
+    if (kvm_enabled() && s->vbe_mapped) {
+        kvm_log_start(VBE_DISPI_LFB_PHYSICAL_ADDRESS, s->vram_size);
+    }
+#endif
+
 }
 
 /*
@@ -2294,6 +2309,15 @@ void vga_init(VGACommonState *s)
     qemu_register_coalesced_mmio(isa_mem_base + 0x000a0000, 0x20000);
 }
 
+void vga_init_vbe(VGACommonState *s)
+{
+#ifdef CONFIG_BOCHS_VBE
+    /* XXX: use optimized standard vga accesses */
+    cpu_register_physical_memory(VBE_DISPI_LFB_PHYSICAL_ADDRESS,
+                                 VGA_RAM_SIZE, s->vram_offset);
+    s->vbe_mapped = 1;
+#endif 
+}
 /********************************************************/
 /* vga screen dump */
 
diff --git a/hw/vga_int.h b/hw/vga_int.h
index c03c220..b5302c1 100644
--- a/hw/vga_int.h
+++ b/hw/vga_int.h
@@ -71,8 +71,8 @@
     uint16_t vbe_regs[VBE_DISPI_INDEX_NB];      \
     uint32_t vbe_start_addr;                    \
     uint32_t vbe_line_offset;                   \
-    uint32_t vbe_bank_mask;
-
+    uint32_t vbe_bank_mask;			\
+    int vbe_mapped;
 #else
 
 #define VGA_STATE_COMMON_BOCHS_VBE
@@ -217,6 +217,7 @@ void vga_draw_cursor_line_32(uint8_t *d1, const uint8_t *src1,
                              unsigned int color_xor);
 
 int vga_ioport_invalid(VGACommonState *s, uint32_t addr);
+void vga_init_vbe(VGACommonState *s);
 
 extern const uint8_t sr_mask[8];
 extern const uint8_t gr_mask[16];
diff --git a/hw/vmware_vga.c b/hw/vmware_vga.c
index 28bbc3f..07befc8 100644
--- a/hw/vmware_vga.c
+++ b/hw/vmware_vga.c
@@ -1129,12 +1129,8 @@ static void vmsvga_init(struct vmsvga_state_s *s, int vga_ram_size)
                                      vmsvga_screen_dump,
                                      vmsvga_text_update, s);
 
-#ifdef CONFIG_BOCHS_VBE
-    /* XXX: use optimized standard vga accesses */
-    cpu_register_physical_memory(VBE_DISPI_LFB_PHYSICAL_ADDRESS,
-                                 vga_ram_size, s->vga.vram_offset);
-#endif
-     rom_add_vga(VGABIOS_FILENAME);
+    vga_init_vbe(&s->vga);
+    rom_add_vga(VGABIOS_FILENAME);
 }
 
 static void pci_vmsvga_map_ioport(PCIDevice *pci_dev, int region_num,
-- 
1.6.5.2