Re: Bug report: the extended PCI config space is missed with 6.2-rc2

[Linux kernel regression tracking (#adding)]

[TLDR: I'm adding this report to the list of tracked Linux kernel
regressions; all text you find below is based on a few templates
paragraphs you might have encountered already already in similar form.
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On 04.01.23 15:39, Liang, Kan wrote:
> Hi Bjorn,
> 
> Happy new year!
> 
> We found some PCI issues with the latest 6.2-rc2.
> 
> - Using the lspci -xxxx, the extended PCI config space of all PCI
> devices are missed with the latest 6.2-rc2. The system we used had 932
> PCI devices, at least 800 which have extended space as seen when booted
> into a 5.15 kernel. But none of them appeared in 6.2-rc2.
> - The drivers which rely on the information in the extended PCI config
> space don't work anymore. We have confirmed that the perf uncore driver
> (uncore performance monitoring) and Intel VSEC driver (telemetry) don't
> work in 6.2-rc2. There could be more drivers which are impacted.
> 
> After a bisect, we found the regression is caused by the below commit
> 07eab0901ede ("efi/x86: Remove EfiMemoryMappedIO from E820 map").
> After reverting the commit, the issues are gone.
> 
> Could you please take a look at the issues?

Thanks for the report. To be sure the issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
tracking bot:

#regzbot ^introduced 07eab0901ede
#regzbot title x86/pci:  extended PCI config space is missed
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply and tell me -- ideally
while also telling regzbot about it, as explained by the page listed in
the footer of this mail.

Reminder for developers: When fixing the issue, add 'Link:' tags
pointing to the report (see page linked in footer for details).

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
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