Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Hi Gerd,


> I'd strongly suggest to move forward to qemu 1.0.  Memory region
> handling has seen a major rewrite in 1.0 (memory api patches by avi).
> Chances are good that the 64bit bar bugs in qemu have been fixed meanwhile.
Thanks, will try it. Hope it will be better.
> I have experimental patches which add a 64bit bar to the qxl device and
> seabios handles it just fine (although memory-backed not mmio), except
> that there is no support yet to map 64bit bars above 4G.
>
> It shouldn't be that hard to add the latter though.  seabios needs two
> more pci_region_type (PCI_REGION_TYPE_MEM_64 and
> PCI_REGION_TYPE_PREFMEM_64) to track and map 64bit bars separately.  And
> a address space window where it can map 64bit bars to.
Right. This is a thing I'm thinking about now. I seems that the 
specifying 0x0 address in 64bit BARS is a bad idea. At least older 
versions of Linux just hang as soon as requested range does not fit in 
first 4GB.
So the only option would be specifying the particular address range. It 
seems this works for everything - yet.
> > Sorry that I haven't specified all this initially. I just want to make
> > 64bit PCI bar working properly. Linux guests works correctly (except
> > early versions - not investigated this yet). At the moment I have some
> > issues with windows which relies on ACPI _CRS.
> ... and a _CRS entry for the 64bit bar address space window of course.
Yes.

Cheers,
Alexey