Patchwork vga: fix vram double-mapping with -vga std and -M pc-0.12

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Submitter Avi Kivity
Date May 9, 2012, 3:23 p.m.
Message ID <1336576986-14390-1-git-send-email-avi@redhat.com>
Download mbox | patch
Permalink /patch/157995/
State New
Headers show

Comments

Avi Kivity - May 9, 2012, 3:23 p.m.
With pc-0.12, we map the video RAM both through the PCI BAR (the guest does
this) and through a fixed mapping at 0xe0000000.  The memory API doesn't allow
this double map, and aborts.

Fix by using an alias.

Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 hw/vga.c     |    7 ++++++-
 hw/vga_int.h |    1 +
 2 files changed, 7 insertions(+), 1 deletion(-)
Michael Tokarev - May 9, 2012, 4:39 p.m.
On 09.05.2012 19:23, Avi Kivity wrote:
> With pc-0.12, we map the video RAM both through the PCI BAR (the guest does
> this) and through a fixed mapping at 0xe0000000.  The memory API doesn't allow
> this double map, and aborts.
> 
> Fix by using an alias.

This appears to work now, at least with -M pc-0.12 -vga std, a win7 guest
boots and works (before qemu were aborting at startup).  So you can add

Tested-By: Michael Tokarev <mjt@tls.msk.ru>

if necessary.  Thank you for the quick fix!

/mjt
Avi Kivity - May 14, 2012, 10:07 a.m.
On 05/09/2012 06:23 PM, Avi Kivity wrote:
> With pc-0.12, we map the video RAM both through the PCI BAR (the guest does
> this) and through a fixed mapping at 0xe0000000.  The memory API doesn't allow
> this double map, and aborts.
>
> Fix by using an alias.
>
>

Ping; should be 1.1ed.
Anthony Liguori - May 30, 2012, 2:13 a.m.
On 05/09/2012 11:23 PM, Avi Kivity wrote:
> With pc-0.12, we map the video RAM both through the PCI BAR (the guest does
> this) and through a fixed mapping at 0xe0000000.  The memory API doesn't allow
> this double map, and aborts.
>
> Fix by using an alias.
>
> Reported-by: Michael Tokarev<mjt@tls.msk.ru>
> Signed-off-by: Avi Kivity<avi@redhat.com>

Applied.  Thanks.

Regards,

Anthony Liguori

> ---
>   hw/vga.c     |    7 ++++++-
>   hw/vga_int.h |    1 +
>   2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/hw/vga.c b/hw/vga.c
> index 5824f85..d784df7 100644
> --- a/hw/vga.c
> +++ b/hw/vga.c
> @@ -2357,10 +2357,15 @@ void vga_init(VGACommonState *s, MemoryRegion *address_space,
>   void vga_init_vbe(VGACommonState *s, MemoryRegion *system_memory)
>   {
>   #ifdef CONFIG_BOCHS_VBE
> +    /* With pc-0.12 and below we map both the PCI BAR and the fixed VBE region,
> +     * so use an alias to avoid double-mapping the same region.
> +     */
> +    memory_region_init_alias(&s->vram_vbe, "vram.vbe",
> +&s->vram, 0, memory_region_size(&s->vram));
>       /* XXX: use optimized standard vga accesses */
>       memory_region_add_subregion(system_memory,
>                                   VBE_DISPI_LFB_PHYSICAL_ADDRESS,
> -&s->vram);
> +&s->vram_vbe);
>       s->vbe_mapped = 1;
>   #endif
>   }
> diff --git a/hw/vga_int.h b/hw/vga_int.h
> index 7685b2b..d244d8f 100644
> --- a/hw/vga_int.h
> +++ b/hw/vga_int.h
> @@ -105,6 +105,7 @@ typedef struct VGACommonState {
>       MemoryRegion *legacy_address_space;
>       uint8_t *vram_ptr;
>       MemoryRegion vram;
> +    MemoryRegion vram_vbe;
>       uint32_t vram_size;
>       uint32_t latch;
>       MemoryRegion *chain4_alias;

Patch

diff --git a/hw/vga.c b/hw/vga.c
index 5824f85..d784df7 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -2357,10 +2357,15 @@  void vga_init(VGACommonState *s, MemoryRegion *address_space,
 void vga_init_vbe(VGACommonState *s, MemoryRegion *system_memory)
 {
 #ifdef CONFIG_BOCHS_VBE
+    /* With pc-0.12 and below we map both the PCI BAR and the fixed VBE region,
+     * so use an alias to avoid double-mapping the same region.
+     */
+    memory_region_init_alias(&s->vram_vbe, "vram.vbe",
+                             &s->vram, 0, memory_region_size(&s->vram));
     /* XXX: use optimized standard vga accesses */
     memory_region_add_subregion(system_memory,
                                 VBE_DISPI_LFB_PHYSICAL_ADDRESS,
-                                &s->vram);
+                                &s->vram_vbe);
     s->vbe_mapped = 1;
 #endif 
 }
diff --git a/hw/vga_int.h b/hw/vga_int.h
index 7685b2b..d244d8f 100644
--- a/hw/vga_int.h
+++ b/hw/vga_int.h
@@ -105,6 +105,7 @@  typedef struct VGACommonState {
     MemoryRegion *legacy_address_space;
     uint8_t *vram_ptr;
     MemoryRegion vram;
+    MemoryRegion vram_vbe;
     uint32_t vram_size;
     uint32_t latch;
     MemoryRegion *chain4_alias;