Re: port-xen/53267 (XEN amd64 DomU (Dom0??) NetBSD current USERMODE() fails)

[Robert Elz <kre%munnari.OZ.AU@localhost>]

The following reply was made to PR port-xen/53267; it has been noted by GNATS.

From: Robert Elz <kre%munnari.OZ.AU@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: cherry%netbsd.org@localhost
Subject: Re: port-xen/53267 (XEN amd64 DomU (Dom0??) NetBSD current USERMODE() fails)
Date: Wed, 09 May 2018 06:02:44 +0700

 I have done a kernel bisect on -current from when netbsd-8 was branched,
 until (more or less) now, and found that before the following mods,
 the XEN USERMODE() macro was performing correctly, and after them
 it is not (it always says "kernel mode" - so does the KERNELMODE()
 macro, not very surprisingly).
 
 That is, I tried kernels from immediately before, and immediately after,
 this set of mods, and it worked before, failed after.
 
 cherry - can you have a look and see if you can see why your changes broke
 this, and perhaps find a suitable fix?
 
 commit 2017.11.06.15.21.23 cherry src/sys/arch/xen/conf/files.xen 1.163
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/x86/xen_ipi.c 1.23
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xen/clock.c 1.65
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xen/if_xennet_xenbus.c 1.72
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xen/xbd_xenbus.c 1.77
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xen/xbdback_xenbus.c 1.64
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xen/xencons.c 1.42
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xen/xennetback_xenbus.c 1.60
 commit 2017.11.06.15.27.09 cherry src/sys/arch/xen/xenbus/xenbus_comms.c 1.16
 
 If you haven't been following the PR, an easy test is
 
 	cgdconfig -g -o /tmp/P aes-cbc 192
 
 (no actual cgd is needed or involved, this simply writes a params file)
 If it loops (seemingly) forever,  USERMODE() is broken.   If it completes
 withing 5 seconds or so all is OK.   (I was actually running with a
 version fo cgdconfig with debug printfs to display the user/sys times being
 returned, but that's not needed to use cgdconfig to detect the bug.)
 
 kre