Re: [PATCH] x86/EISA: Don't probe EISA bus for Xen PV guests

From: Boris Ostrovsky
Date: Tue Sep 11 2018 - 16:29:07 EST

On 9/11/18 4:20 PM, Thomas Gleixner wrote:
> On Tue, 11 Sep 2018, Boris Ostrovsky wrote:
>> For unprivileged Xen PV guests this is normal memory and ioremap will
>> not be able to properly map it.
>> While at it, since ioremap may return NULL, add a test for pointer's
>> validity.
> I assume this goes back to very dead kernels, so that should go with a Cc
> stable, right?

Yes, I forgot to add those (and now I did), thanks for pointing this out.

It has to go at least all the way back to 4.13 since before
f7eaf6e00fd58 ("x86/boot: Move EISA setup to a separate file"), just by
luck, early_ioremap() worked for the guests.