[edk2-devel] UefiPayloadPkg and over-eager PCI resource allocation?

[Benjamin You]

Hi,

Current PCI Host Bridge driver treats resources reported from root bridges
as continuous and performs rigorous checking against overlaps with existing
resources such as MMCONF.

I think to support the case where a root bridge reports a non-continuous range
that encompasses the MMCONF, a policy could be defined for the PCI Host Bridge
driver to optionally carve out the MMCONF from the root bridge MMIO resources
reported to GCD. (MMCONF is defined by PcdPciExpressBaseAddress and 
PcdPciExpressBaseSize). A PCD could be defined to enable such behavior (with 
default as FALSE to maintain backward compatibility).

Thanks,

- ben

> -----Original Message-----
> From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Guo Dong
> Sent: Monday, January 4, 2021 11:17 AM
> To: devel at edk2.groups.io; mjg59 at srcf.ucam.org
> Subject: Re: [edk2-devel] UefiPayloadPkg and over-eager PCI resource
> allocation?
> 
> 
> Hi,
> 
> The pcihostbridgelib  in the uefipayloadpkg would scan the PCI bridge to collect
> the assigned PCI resource information.
> During scanning, there is an assumption that the PCI memory resource is
> allocated continuously without gaps.
> 
> In your case, it looks the lowest resource address is 9F800000, and the high
> resource address is FE0FFFFF.
> There is a gap (0xE0000000 ~ 0xF0000000) between them used for PCIe base
> address.
> 
> You could check which PCI device is assigned with FE0FFFFF in coreboot, and
> change it before 0xE0000000.
> 
> I am thinking we could update pcihostbridgelib to get the PCI resource
> information from bootloader (coreboot and SBL)
> instead of scanning the PCI bridge to get the range. Let me know if having
> comments.
> 
> Thanks,
> Guo
> 
> > -----Original Message-----
> > From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Matthew
> > Garrett
> > Sent: Sunday, December 27, 2020 1:41 PM
> > To: devel at edk2.groups.io
> > Subject: [edk2-devel] UefiPayloadPkg and over-eager PCI resource allocation?
> >
> > I'm trying to run UefiPayloadPkg on a Coreboot-based system. Based on
> > debug logs, my GCD looks like this:
> >
> > GCDMemType Range                             Capabilities     Attributes
> > ========== ================================= ================
> > ================
> > Reserved   0000000000000000-0000000000000FFF 870000000000000F
> > 0000000000000000
> > SystemMem  0000000000001000-000000000009FFFF 800000000000000F
> > 0000000000000000*
> > Reserved   00000000000A0000-00000000000FFFFF 870000000000000F
> > 0000000000000000
> > SystemMem  0000000000100000-0000000099A5DFFF 800000000000000F
> > 0000000000000000*
> > Reserved   0000000099A5E000-000000009F7FFFFF 870000000000000F
> > 0000000000000000
> > NonExist   000000009F800000-00000000DFFFFFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000E0000000-00000000EFFFFFFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000F0000000-00000000FBFFFFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000FC000000-00000000FC000FFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000FC001000-00000000FDFFFFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000FE000000-00000000FE00FFFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000FE010000-00000000FEC7FFFF 0000000000000000
> > 0000000000000000
> > MMIO       00000000FEC80000-00000000FECFFFFF C700000000000001
> > 0000000000000000*
> > NonExist   00000000FED00000-00000000FED0FFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000FED10000-00000000FED17FFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000FED18000-00000000FED7FFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000FED80000-00000000FED83FFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000FED84000-00000000FED8FFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000FED90000-00000000FED91FFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000FED92000-00000000FED9FFFF 0000000000000000
> > 0000000000000000
> > Reserved   00000000FEDA0000-00000000FEDA1FFF 870000000000000F
> > 0000000000000000
> > NonExist   00000000FEDA2000-00000000FFFFFFFF 0000000000000000
> > 0000000000000000
> > Reserved   0000000100000000-000000085F7FFFFF 830000000000000F
> > 0000000000000000
> > NonExist   000000085F800000-0000007FFFFFFFFF 0000000000000000
> > 0000000000000000
> >
> > At boot I hit an assertion:
> >
> > PciHostBridgeDxe: IntersectMemoryDescriptor: desc [E0000000, F0000000)
> > type 1 cap 870000000002600F conflicts with aperture [9F800000,FE100000)
> > cap 1
> >
> > which is, at face value, legitimate. However, e0000000 is the MMCONF
> > window, and this is where I'd expect it to be. 9f800000 is the base of
> > the PCIe host bridge aperture, which is also where I'd expect it to be.
> > Coreboot seems to think that this should all work:
> >
> >  DOMAIN: 0000: Resource ranges:
> >  * Base: 9f800000, Size: 40800000, Tag: 200
> >  * Base: f0000000, Size: c000000, Tag: 200
> >  * Base: fc001000, Size: 1fff000, Tag: 200
> >  * Base: fe010000, Size: d00000, Tag: 200
> >  * Base: fed18000, Size: 68000, Tag: 200
> >  * Base: fed84000, Size: c000, Tag: 200
> >  * Base: fed92000, Size: e000, Tag: 200
> >  * Base: feda2000, Size: 125e000, Tag: 200
> >  * Base: 85f800000, Size: 77a0800000, Tag: 100200
> >
> > 9f800000+40800000 is e0000000, so that seems fine. There's also some
> > other windows, but nothing that collides with the MMCONF region. But
> > when we get to Tiano:
> >
> > PciRoot(0x0)
> >   Support/Attr: 7001F / 7001F
> >     DmaAbove4G: No
> > NoExtConfSpace: No
> >      AllocAttr: 0 ()
> >            Bus: 0 - 3 Translation=0
> >             Io: 1000 - EFFF Translation=0
> >            Mem: 9F800000 - FE0FFFFF Translation=0
> >
> > Which obviously collides with MMCONF, along with a couple of other
> > allocations. Is it trying to merge the entire range of MMIO regions into
> > a single aperture? Does this seem like a Coreboot or a UefiPayloadPkg
> > issue?
> >
> >
> >
> >
> 
> 
> 
> 
> 



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