CVS commit: [netbsd-10] src/sys/arch/xen/xen

[Martin Husemann]

Module Name:    src
Committed By:   martin
Date:           Wed Jul 19 14:31:40 UTC 2023

Modified Files:
        src/sys/arch/xen/xen [netbsd-10]: xen_clock.c

Log Message:
Pull up following revision(s) (requested by bouyer in ticket #238):

        sys/arch/xen/xen/xen_clock.c: revision 1.10
        sys/arch/xen/xen/xen_clock.c: revision 1.12

Unmask event after VCPUOP_stop_periodic_timer and
initializing ci->ci_xen_hardclock_systime_ns, to avoid a possible race with
xen_timer_handler()

Unmask event after arming the one-shot timer in clock initialisation,
to avoid a possible race with xen_timer_handler() updating
ci_xen_hardclock_systime_ns while we're reading it.

Pointed out by Taylor R Campbell


To generate a diff of this commit:
cvs rdiff -u -r1.8 -r1.8.18.1 src/sys/arch/xen/xen/xen_clock.c

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


Modified files:

Index: src/sys/arch/xen/xen/xen_clock.c
diff -u src/sys/arch/xen/xen/xen_clock.c:1.8 src/sys/arch/xen/xen/xen_clock.c:1.8.18.1
--- src/sys/arch/xen/xen/xen_clock.c:1.8	Mon Nov 30 17:05:02 2020
+++ src/sys/arch/xen/xen/xen_clock.c	Wed Jul 19 14:31:40 2023
@@ -1,4 +1,4 @@
-/*	$NetBSD: xen_clock.c,v 1.8 2020/11/30 17:05:02 bouyer Exp $	*/
+/*	$NetBSD: xen_clock.c,v 1.8.18.1 2023/07/19 14:31:40 martin Exp $	*/
 
 /*-
  * Copyright (c) 2017, 2018 The NetBSD Foundation, Inc.
@@ -36,7 +36,7 @@
 #endif
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xen_clock.c,v 1.8 2020/11/30 17:05:02 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xen_clock.c,v 1.8.18.1 2023/07/19 14:31:40 martin Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -639,7 +639,6 @@ xen_resumeclocks(struct cpu_info *ci)
 	    ci, IPL_CLOCK, NULL, intr_xname, true, ci) == NULL)
 		panic("failed to establish timer interrupt handler");
 
-	hypervisor_unmask_event(evtch);
 
 	aprint_verbose("Xen %s: using event channel %d\n", intr_xname, evtch);
 
@@ -653,10 +652,12 @@ xen_resumeclocks(struct cpu_info *ci)
 	/* Pretend the last hardclock happened right now.  */
 	ci->ci_xen_hardclock_systime_ns = xen_vcputime_systime_ns();
 
+
 	/* Arm the one-shot timer.  */
 	error = HYPERVISOR_set_timer_op(ci->ci_xen_hardclock_systime_ns +
 	    NS_PER_TICK);
 	KASSERT(error == 0);
+	hypervisor_unmask_event(evtch);
 
 	/* We'd better not have switched CPUs.  */
 	KASSERT(ci == curcpu());