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

From: Tomasz Pala <gotar@polanet.pl>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org,
	"Dan J Williams" <dan.j.williams@intel.com>,
	"Kan Liang" <kan.liang@linux.intel.com>,
	"Tony Luck" <tony.luck@intel.com>,
	"David E Box" <david.e.box@intel.com>,
	"Yunying Sun" <yunying.sun@intel.com>,
	"Dave Jiang" <dave.jiang@intel.com>,
	"Mika Westerberg" <mika.westerberg@linux.intel.com>,
	"Giovanni Cabiddu" <giovanni.cabiddu@intel.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Florent DELAHAYE" <linuxkernelml@undead.fr>,
	"Konrad J Hambrick" <kjhambrick@gmail.com>,
	"Matt Hansen" <2lprbe78@duck.com>,
	"Nicholas Johnson" <nicholas.johnson-opensource@outlook.com.au>,
	"Benoit Grégoire" <benoitg@coeus.ca>,
	"Werner Sembach" <wse@tuxedocomputers.com>,
	mumblingdrunkard@protonmail.com, linux-kernel@vger.kernel.org,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Sebastian Manciulea" <manciuleas@protonmail.com>
Subject: Re: [PATCH 2/2] x86/pci: Treat EfiMemoryMappedIO as reservation of ECAM space
Date: Sat, 18 Nov 2023 15:21:43 +0100	[thread overview]
Message-ID: <20231118142143.GA14101@polanet.pl> (raw)
In-Reply-To: <20231109184405.GA488882@bhelgaas>

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@pld-linux.org>