Re: PCI arbiter crash on last qemu image

[Samuel Thibault]

Damien Zammit, le lun. 07 sept. 2020 11:16:13 +1000, a ecrit:
> On 6/9/20 11:17 pm, Samuel Thibault wrote:
> > One issue remains, however: Xorg's vesa driver produces
> > 
> > [1669282.478] (II) VESA(0): initializing int10
> > [1669282.478] (EE) VESA(0): Cannot read int vect
> > 
> > which comes from hw/xfree86/int10/generic.c xf86ExtendedInitInt10:
> > 
> >     if (!sysMem)
> >         pci_device_map_legacy(pInt->dev, V_BIOS, BIOS_SIZE + SYS_BIOS - 
> > V_BIOS,
> >                               PCI_DEV_MAP_FLAG_WRITABLE, &sysMem);
> 
> It appears that it's trying to map more than BIOS_SIZE, which probably fails 
> under the current scheme. 
> Perhaps we need to make overreads return zeroes instead of failure?

No, that part of the code works fine.

Looking closer, I noticed that in 

  if (!readIntVec(pInt->dev, base, LOW_PAGE_SIZE)) {

LOW_PAGE_SIZE is 0x600, that's what is passed as len in

  if (pci_device_map_legacy(dev, 0, len, 0, &map))

So I guess that the problem is that gnu's version of map_dev_mem is
missing rounding up the len like mmap does.

Samuel