CVS commit: src/sys/arch/x86/x86

["Cherry G. Mathew" <cherry%netbsd.org@localhost>]

Module Name:    src
Committed By:   cherry
Date:           Thu Sep 20 05:08:45 UTC 2018

Modified Files:
        src/sys/arch/x86/x86: intr.c

Log Message:
When we removed the XEN special case from isa/isa_machdep.c
there was a corner case that was missed in
x86/intr.c:intr_establish_xname()

In isa_machdep.c:isa_intr_establish_xname() the legacy_irq parameter
is never set to -1. It is also incorrect to call
isa_intr_establish_xname() with a legacy_irq parameter of -1.

Thus we infer that whenever we see (legacy_irq == -1) in
intr_establish_xname() which is downstream, we were *NOT* called from
isa_machdep.c:isa_intr_establish_xname()

Given that there are no other users of intr_establish_xnam() which
pass a valid legacy_irq != -1, we assume therefore that we *WERE*
called from isa_machdep.c:isa_intr_establish_xname() in this case.

This is an important distinction in the case where a valid
legacy_irq > NUM_LEGACY_IRQS was passed down from
isa_intr_establish_xname() but was ignored by xen_pirq_alloc() and
overwritten with the "pseudo" irq which is then passed back. We thus
pass the incorrect "legacy" irq value to pirq_establish().

Even though non ISA (ie; PCI and MSI(X) cases), this is the correct
behaviour, we need to maintain (bug?) compatibility with the isa
case.

Thus the one liner diff.

CVS: ----------------------------------------------------------------------
CVS: CVSROOT  cvs.NetBSD.org:/cvsroot
CVS: please use "PR category/123" to have the commitmsg appended to PR 123
CVS:
CVS: Please evaluate your changes and consider the following.
CVS: Abort checkin if you answer no.
CVS: => For all changes:
CVS: Do the changed files compile?
CVS: Has the change been tested?
CVS: => If you are not completely familiar with the changed components:
CVS: Has the change been posted for review?
CVS: Have you allowed enough time for feedback?
CVS: => If the change is major:
CVS: => If the change adds files to, or removes files from $DESTDIR:
CVS: => If you are changing a library or kernel interface:
CVS: Have you successfully run "./build.sh release"?


To generate a diff of this commit:
cvs rdiff -u -r1.129 -r1.130 src/sys/arch/x86/x86/intr.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.