linux-kernel - Re: [PATCH 2/2] x86/pci: Treat EfiMemoryMappedIO as reservation of ECAM space

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Date:   Sat, 18 Nov 2023 15:21:43 +0100
From:   Tomasz Pala <gotar@...anet.pl>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     linux-pci@...r.kernel.org,
        Dan J Williams <dan.j.williams@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        David E Box <david.e.box@...el.com>,
        Yunying Sun <yunying.sun@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Giovanni Cabiddu <giovanni.cabiddu@...el.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Hans de Goede <hdegoede@...hat.com>,
        Florent DELAHAYE <linuxkernelml@...ead.fr>,
        Konrad J Hambrick <kjhambrick@...il.com>,
        Matt Hansen <2lprbe78@...k.com>,
        Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>,
        Benoit Grégoire <benoitg@...us.ca>,
        Werner Sembach <wse@...edocomputers.com>,
        mumblingdrunkard@...tonmail.com, linux-kernel@...r.kernel.org,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Sebastian Manciulea <manciuleas@...tonmail.com>
Subject: Re: [PATCH 2/2] x86/pci: Treat EfiMemoryMappedIO as reservation of
 ECAM space

On Thu, Nov 09, 2023 at 12:44:05 -0600, Bjorn Helgaas wrote:

>> https://bugzilla.kernel.org/show_bug.cgi?id=218050
>> 
>> I think the problem is that the MMCONFIG region is at
>> [mem 0x80000000-0x8fffffff], and that is *also* included in one of the
>> host bridge windows reported via _CRS:
>> 
>>   PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem 0x80000000-0x8fffffff] (base 0x80000000)
>>   pci_bus 0000:00: root bus resource [mem 0x80000000-0xfbffffff window]
>> 
>> I'll try to figure out how to deal with that.  In the meantime, would
>> you mind attaching the contents of /proc/iomem to the bugzilla?  I
> 
> I attached a debug patch to both bugzilla entries.  If you could
> attach the "acpidump" output and (if practical) boot a kernel with the
> debug patch and attach the dmesg logs, that would be great.

I've posted the files. There are signs of buggy BIOS, but I don't expect
any firmware update to be released for this hw anymore.

DMI: Supermicro X9DRi-LN4+/X9DR3-LN4+/X9DRi-LN4+/X9DR3-LN4+, BIOS 3.4 11/20/2019

.text .data .bss are not marked as E820_TYPE_RAM!
tboot: non-0 tboot_addr but it is not of type E820_TYPE_RESERVED

DMAR: [Firmware Bug]: No firmware reserved region can cover this RMRR [0x00000000df243000-0x00000000df251fff], contact BIOS vendor for fixes
DMAR: [Firmware Bug]: Your BIOS is broken; bad RMRR [0x00000000df243000-0x00000000df251fff]



BTW is there a reason for this logging discrepancy?

efi: Remove mem173: MMIO range=[0xe0000000-0xefffffff] (256MB) from e820 map
efi: Not removing mem71: MMIO range=[0xe0000000-0xefffffff] (262144KB) from e820 map

efi: Not removing mem74: MMIO range=[0xff000000-0xffffffff] (16384KB) from e820 map
efi: Remove mem176: MMIO range=[0xff000000-0xffffffff] (16MB) from e820 map

This is arch/x86/platform/efi/efi.c:
static void __init efi_remove_e820_mmio(void)

Remove mem%02u: MMIO range=[0x%08llx-0x%08llx] (%lluMB) ... size >> 20
Not removing mem%02u: MMIO range=[0x%08llx-0x%08llx] (%lluKB) ... size >> 10

-- 
Tomasz Pala <gotar@...-linux.org>