Re: Info: mapping multiple BARs. Your kernel is fine.

Borislav Petkov
2014-04-17T10:45:33Z

Hi Bjorn,

thanks for the patch, a couple of notes below:

On Wed, Apr 16, 2014 at 04:56:00PM -0600, Bjorn Helgaas wrote:
> PNP: Work around Haswell BIOS defect in MCH area reporting
>
> From: Bjorn Helgaas <bhelgaas@google.com>
>
> Work around a Haswell BIOS defect that causes part of the MCH area to be
> unreported.

Yep, what Stephane said, this is not HSW only.

> MCHBAR is not an architected PCI BAR, so MCH space is usually reported as a
> PNP0C02 resource. The MCH space was 16KB prior to Haswell, but it is 32KB
> in Haswell. Some Haswell BIOSes still report a PNP0C02 resource that is
> only 16KB, which means the rest of the MCH space is consumed but
> unreported.
>
> This can cause resource map sanity check warnings or (theoretically) a
> device conflict if we assigned the unreported space to another device.
>
> The Intel perf event uncore driver tripped over this when it claimed the
> MCH region:
>
> resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
> Info: mapping multiple BARs. Your kernel is fine.
>
> To prevent this, if we find a PNP0C02 resource that covers part of the MCH
> space, extend it to cover the entire space.
>
> Link: http://lkml.kernel.org/r/20140224162400.GE16457@pd.tnic
> Reported-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
> drivers/pnp/quirks.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 55 insertions(+)
>
> diff --git a/drivers/pnp/quirks.c b/drivers/pnp/quirks.c
> index 258fef272ea7..8402088d4145 100644
> --- a/drivers/pnp/quirks.c
> +++ b/drivers/pnp/quirks.c
> @@ -334,6 +334,60 @@ static void quirk_amd_mmconfig_area(struct pnp_dev *dev)
> }
> #endif
>
> +static void quirk_intel_haswell_mch(struct pnp_dev *dev)
> +{
> + struct pci_dev *host;
> + u32 addr_lo, addr_hi;
> + struct pci_bus_region region;
> + struct resource mch;
> + struct pnp_resource *pnp_res;
> + struct resource *res;
> +
> + host = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0c00, NULL);

And because it is not HSW only, this PCI device ID doesn't match on my
IVB system. On mine the hostbridge is

00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09)
Subsystem: Lenovo Device 21fa
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx-
Latency: 0
Capabilities: <access denied>
Kernel driver in use: ivb_uncore
00: 86 80 54 01 06 00 90 20 09 00 00 06 00 00 00 00
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 aa 17 fa 21
30: 00 00 00 00 e0 00 00 00 00 00 00 00 00 00 00 00

and from looking at Dave's, it is the same one, so PCI device ID is
0x154.

With that changed to

host = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0154, NULL);

and a bit of debugging code, it says now:

[ 0.235739] quirk_intel_haswell_mch: entry
[ 0.235800] quirk_intel_haswell_mch: got host: 0x0
[ 0.235860] quirk_intel_haswell_mch: mch: [mem 0xfed10000-0xfed17fff]
[ 0.235930] quirk_intel_haswell_mch: res: [mem 0xfed10000-0xfed13fff]
[ 0.235990] pnp 00:01: [Firmware Bug]: [mem 0xfed10000-0xfed13fff] covers only part of Intel Haswell MCH; extending to [mem 0xfed10000-0xfed17fff]

So you probably want to have a list of hostbridge pci ids in the quirk
or so.

Thanks.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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