Re: [Qemu-devel] [PULL for-1.8 1/2] pc: disable pci-info

[Michael S. Tsirkin]

On Tue, Nov 26, 2013 at 04:59:33PM +0100, Gerd Hoffmann wrote:
> 
>   Hi,
> 
> > > > Yes, I think it's a start. Q35 is a bit harder because of the MMIO
> > > > region.
> > > 
> > > ???  Do you mean mmconfig?  That can live inside the window.
> > 
> > Are you sure? When I tried windows crashed but maybe I'm wrong.
> > Did you try some windows guests?
> 
> At least it looks that way on my laptop:
> 
> nilsson root ~# cat /proc/iomem 
> [ ... ]
> dfa00000-febfffff : PCI Bus 0000:00
>   [ ... ]
>   f8000000-fbffffff : PCI MMCONFIG 0000 [bus 00-3f]
>     f80f8000-f80f8fff : reserved
> fec00000-fec003ff : IOAPIC 0
> [ ... ]


True. Mine also has:
_CRS in DSDT:

                DWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed, 
Cacheable, ReadWrite,
                    0x00000000,         // Granularity
                    0x00100000,         // Range Minimum
                    0xFEBFFFFF,         // Range Maximum
                    0x00000000,         // Translation Offset
                    0xFEB00000,         // Length
                    ,, _Y23, AddressRangeMemory, TypeStatic)

MCFG
[02Ch 0044  8]                 Base Address : 00000000F8000000
[034h 0052  2]         Segment Group Number : 0000
[036h 0054  1]             Start Bus Number : 00
[037h 0055  1]               End Bus Number : 3F
[038h 0056  4]                     Reserved : 00000000

so they do overlap apparently without issues.

Well, this definitely simplifies things: this probably means we can just
do the same thing for piix and q35.



> The reservation seems to be different from what we are doing though.  We
> (aka seabios) are creating a e820 reserved region, on my laptop mmconfig
> is declared in acpi:
> 
> nilsson root ~# grep f8000000 /var/log/dmesg
> [    0.103320] PCI: MMCONFIG for domain 0000 [bus 00-3f] at [mem
> 0xf8000000-0xfbffffff] (base 0xf8000000)
> [    0.126943] PCI: MMCONFIG for domain 0000 [bus 00-3f] at [mem
> 0xf8000000-0xfbffffff] (base 0xf8000000)
> [    0.128697] PCI: MMCONFIG at [mem 0xf8000000-0xfbffffff] reserved in
> ACPI motherboard resources
> [    0.160979] system 00:01: [mem 0xf8000000-0xfbffffff] could not be
> reserved
> 
> Maybe this is what windows doesn't like ...
> 
> cheers,
>   Gerd
> 
>