Re: Missing sriov_numvfs after removal of EfiMemoryMappedIO from E820 map

["Linux kernel regression tracking (Thorsten Leemhuis)" <regressions@leemhuis.info>]

[CCing the regression list, as it should be in the loop for regressions:
https://docs.kernel.org/admin-guide/reporting-regressions.html]

Hi, this is your Linux kernel regression tracker.

On 15.01.23 10:21, Peifeng Qiu wrote:
> 
> I'm using a dual Xeon system with Intel e810 25G network card and make use
> of SRIOV feature heavily. I have a script to setup the NIC the first step is
> echo $VFS > /sys/class/net/$DEVNAME/device/sriov_numvfs
> 
> After switching from v6.1 to v6.2-rc1 "sriov_numvfs" is no longer present. If I
> switch back to v6.1 it's back. Command line parameters are the same so it's
> most likely kernel changes. I did git bisect and found the culprit to be
> 07eab0901ed(efi/x86: Remove EfiMemoryMappedIO from E820 map)

This is not my area of expertise, but there is another report about an
issue that was bisected to that particular commit:

https://lore.kernel.org/lkml/ac2693d8-8ba3-72e0-5b66-b3ae008d539d@linux.intel.com/

A fix for that one was posted here:

https://lore.kernel.org/lkml/20230110180243.1590045-1-helgaas@kernel.org/

You might want to look into the report and if it looks like a possible
duplicate give the proposed fix a try.

But as I said, this is not my area of expertise, you hence might want to
wait for the expert to share their view of things.

Anyway, 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 07eab0901ed
#regzbot title pci: sriov_numvfs missing after removal of
EfiMemoryMappedIO from E820 map (possible duplicate)
#regzbot ignore-activity

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

> I tested v6.2-rc3 and it's the same. I reverted this commit on top of v6.2-rc3
> then sriov_numvfs is back again. Comparing the dmesg output, I found that
> with commit 07eab0901ed these lines are present:
> [    0.000000] efi: Remove mem94: MMIO range=[0x80000000-0x8fffffff]
> (256MB) from e820 map
> [    0.000000] e820: remove [mem 0x80000000-0x8fffffff] reserved
> [    0.000000] efi: Remove mem95: MMIO range=[0xfd000000-0xfe7fffff]
> (24MB) from e820 map
> [    0.000000] e820: remove [mem 0xfd000000-0xfe7fffff] reserved
> [    0.000000] efi: Not removing mem96: MMIO
> range=[0xfed20000-0xfed44fff] (148KB) from e820 map
> [    0.000000] efi: Remove mem97: MMIO range=[0xff000000-0xffffffff]
> (16MB) from e820 map
> [    0.000000] e820: remove [mem 0xff000000-0xffffffff] reserved
> [    0.000000] efi: Remove mem99: MMIO
> range=[0x1ffc00000000-0x1fffffffffff] (16384MB) from e820 map
> [    0.000000] e820: remove [mem 0x1ffc00000000-0x1fffffffffff] reserved
> 
> I think that's what the commit actually does. But the following are missing:
> [    2.516119] pci 0000:ca:00.0: reg 0x184: [mem
> 0x208ffd000000-0x208ffd01ffff 64bit pref]
> [    2.516121] pci 0000:ca:00.0: VF(n) BAR0 space: [mem
> 0x208ffd000000-0x208ffdffffff 64bit pref] (contains BAR0 for 128 VFs)
> [    2.516134] pci 0000:ca:00.0: reg 0x190: [mem
> 0x208ffe220000-0x208ffe223fff 64bit pref]
> [    2.516136] pci 0000:ca:00.0: VF(n) BAR3 space: [mem
> 0x208ffe220000-0x208ffe41ffff 64bit pref] (contains BAR3 for 128 VFs)
> 
> Not sure whether this is a driver issue specific to Intel e810(module ice) or
> a more general one. Any thoughts on this issue?
> 
> Best regards,
> Peifeng Qiu