Hi Bjorn,
On 10/20/21 23:14, Bjorn Helgaas wrote:
On Wed, Oct 20, 2021 at 12:23:26PM +0200, Hans de Goede wrote:
On 10/19/21 23:52, Bjorn Helgaas wrote:
On Thu, Oct 14, 2021 at 08:39:42PM +0200, Hans de Goede wrote:
Some BIOS-es contain a bug where they add addresses which map to system RAM in the PCI host bridge window returned by the ACPI _CRS method, see commit 4dc2287c1805 ("x86: avoid E820 regions when allocating address space").
To work around this bug Linux excludes E820 reserved addresses when allocating addresses from the PCI host bridge window since 2010. ...
I haven't seen anybody else eager to merge this, so I guess I'll stick my neck out here.
I applied this to my for-linus branch for v5.15.
Thank you, and sorry about the build-errors which the lkp kernel-test-robot found.
I've just send out a patch which fixes these build-errors (verified with both .config-s from the lkp reports). Feel free to squash this into the original patch (or keep them separate, whatever works for you).
Thanks, I squashed the fix in.
HOWEVER, I think it would be fairly risky to push this into v5.15. We would be relying on the assumption that current machines have all fixed the BIOS defect that 4dc2287c1805 addressed, and we have little evidence for that.
I'm not sure there's significant benefit to having this in v5.15. Yes, the mainline v5.15 kernel would work on the affected machines, but I suspect most people with those machines are running distro kernels, not mainline kernels.
I understand that you were reluctant to add this to 5.15 so close near the end of the 5.15 cycle, but can we please get this into 5.16 now ?
I know you ultimately want to see if there is a better fix, but this is hitting a *lot* of users right now and if we come up with a better fix we can always use that to replace this one later.
So cam we please just go with this fix now, so that we can fix the issues a lot of users are seeing caused by the current *wrong* behavior of taking the e820 reservations into account ?
Regards,
Hans