CVS commit: src/sys/arch/xen/xen

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Fri Nov 10 19:24:17 UTC 2017

Modified Files:
        src/sys/arch/xen/xen: evtchn.c

Log Message:
Fix theoretical race in xen_evtchn_trymask.

This now matches ioapic_trymask:

- Caller masks CPU interrupts while the PIC's interrupts are unmasked.
- Trymask masks the PIC's interrupts, and tests whether any were
  pending that we missed because the CPU interrupts are masked.

  ==> If there were any pending, trymask unmasks PIC's interrupts and
      returns false.

  ==> If not, interrupts are masked on the PIC and CPU and there were
      none pending and trymask returns true.

No functional change right now because cpu_intr_redistribute is
currently disabled on Xen.

ok cherry


To generate a diff of this commit:
cvs rdiff -u -r1.74 -r1.75 src/sys/arch/xen/xen/evtchn.c

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