[SeaBIOS] [PATCH] mark VBE mapping as reserved in e820

Anthony Liguori anthony at codemonkey.ws
Mon Jan 25 16:45:48 CET 2010

On 01/25/2010 09:06 AM, Avi Kivity wrote:
> On 01/24/2010 08:18 PM, Kevin O'Connor wrote:
>> On Sun, Jan 24, 2010 at 12:16:11PM +0200, Avi Kivity wrote:
>>> That's not correct - when running with PCI -vga std _is_ a PCI
>>> device (and it has a BAR).  What's needed is to make the VBE BIOS
>>> aware of it.
>> According to Sebastian, the latest version of vgabios (v0.6c) does
>> support this.  I see that the following was added to vbe.c:
>> +                lfb_addr = pci_get_lfb_addr(0x1234); // experimental 
>> vendor
>> +                if (lfb_addr>  0) {
>> +                  info.PhysBasePtr = ((Bit32u)lfb_addr<<  16);
>> +                }
> It's clear we should pull this for qemu.git master.  But what about 
> 0.12?  I prefer going back to 0xf0* to reduce the risk for further 
> regressions.

This isn't a guest visible change so for 0.12, I would expect that 
bringing in the vgabios changes would be reasonable.  I don't love the 
idea of carrying a different behaviour in SeaBIOS and VGABIOS for 0.12 
than in master.

>> The vgabios code could use an overhaul - it has many of the same
>> maintenance problems that bochs bios has.  A port to gcc would be a
>> big help.  Some time back, I ported the base vga code (see the vgasrc/
>> directory in seabios git), but I haven't looked at the cirrus or vbe
>> extensions.
> That would be great, even though vgabios doesn't see much churn.

Yes, it would remove the BCC dependency on the build which would be 
really nice.


Anthony Liguori

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