kern/135008: commit references a PR
dfilter service
dfilter at FreeBSD.ORG
Thu May 28 04:20:05 UTC 2009
The following reply was made to PR kern/135008; it has been noted by GNATS.
From: dfilter at FreeBSD.ORG (dfilter service)
To: bug-followup at FreeBSD.org
Cc:
Subject: Re: kern/135008: commit references a PR
Date: Thu, 28 May 2009 04:17:16 +0000 (UTC)
Author: adrian
Date: Thu May 28 04:17:05 2009
New Revision: 192953
URL: http://svn.freebsd.org/changeset/base/192953
Log:
Say hello to a very basic, read-only, Xen Hypervisor RTC.
The hypervisor doesn't provide a single "TOD" - it instead provides a
"start time" and a "running time". These are added together to form
the current TOD. The TOD is in UTC.
This RTC is only (initially) designed to be read at startup. There's
some further poking that needs to happen to pick up hypervisor time
changes (ie, by the Dom0 time being adjusted by something). This
time adjustment currently can cause "weird stuff" in the DomU clock;
I'll begin investigating and repairing that in subsequent commits.
PR: 135008
Added:
head/sys/i386/xen/xen_rtc.c (contents, props changed)
Modified:
head/sys/conf/files.i386
Modified: head/sys/conf/files.i386
==============================================================================
--- head/sys/conf/files.i386 Thu May 28 04:08:07 2009 (r192952)
+++ head/sys/conf/files.i386 Thu May 28 04:17:05 2009 (r192953)
@@ -327,6 +327,7 @@ i386/isa/atpic.c optional atpic
#i386/isa/atpic_vector.s standard
i386/isa/clock.c optional native
i386/xen/clock.c optional xen
+i386/xen/xen_rtc.c optional xen
i386/isa/dpms.c optional dpms
i386/isa/elcr.c standard
i386/isa/elink.c optional ep | ie
Added: head/sys/i386/xen/xen_rtc.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/sys/i386/xen/xen_rtc.c Thu May 28 04:17:05 2009 (r192953)
@@ -0,0 +1,191 @@
+/*-
+ * Copyright (c) 2009 Adrian Chadd
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/clock.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/time.h>
+
+#include <xen/xen_intr.h>
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <machine/pmap.h>
+#include <xen/hypervisor.h>
+#include <machine/xen/xen-os.h>
+#include <machine/xen/xenfunc.h>
+#include <xen/interface/io/xenbus.h>
+#include <xen/interface/vcpu.h>
+#include <machine/cpu.h>
+
+#include "clock_if.h"
+
+/*
+ * Read the current hypervisor start time (wall clock) from Xen.
+ */
+static void
+xen_fetch_wallclock(struct timespec *ts)
+{
+ shared_info_t *s = HYPERVISOR_shared_info;
+ uint32_t ts_version;
+
+ do {
+ ts_version = s->wc_version;
+ rmb();
+ ts->tv_sec = s->wc_sec;
+ ts->tv_nsec = s->wc_nsec;
+ rmb();
+ }
+ while ((s->wc_version & 1) | (ts_version ^ s->wc_version));
+}
+
+/*
+ * Read the current hypervisor system uptime value from Xen.
+ */
+static void
+xen_fetch_uptime(struct timespec *ts)
+{
+ shared_info_t *s = HYPERVISOR_shared_info;
+ struct vcpu_time_info *src;
+ struct shadow_time_info dst;
+ uint32_t pre_version, post_version;
+
+ src = &s->vcpu_info[smp_processor_id()].time;
+
+ spinlock_enter();
+ do {
+ pre_version = dst.version = src->version;
+ rmb();
+ dst.system_timestamp = src->system_time;
+ rmb();
+ post_version = src->version;
+ }
+ while ((pre_version & 1) | (pre_version ^ post_version));
+
+ spinlock_exit();
+
+ ts->tv_sec = dst.system_timestamp / 1000000000;
+ ts->tv_nsec = dst.system_timestamp % 1000000000;
+}
+
+
+static int
+xen_rtc_probe(device_t dev)
+{
+ device_set_desc(dev, "Xen Hypervisor Clock");
+ printf("[XEN] xen_rtc_probe: probing Hypervisor RTC clock\n");
+ if (! HYPERVISOR_shared_info) {
+ device_printf(dev, "No hypervisor shared page found; RTC can not start.\n");
+ return (EINVAL);
+ }
+ return (0);
+}
+
+static int
+xen_rtc_attach(device_t dev)
+{
+ printf("[XEN] xen_rtc_attach: attaching Hypervisor RTC clock\n");
+ clock_register(dev, 1000000);
+ return(0);
+}
+
+static int
+xen_rtc_settime(device_t dev __unused, struct timespec *ts)
+{
+ device_printf(dev, "[XEN] xen_rtc_settime\n");
+ /*
+ * Don't return EINVAL here; just silently fail if the domain isn't privileged enough
+ * to set the TOD.
+ */
+ return(0);
+}
+
+/*
+ * The Xen time structures document the hypervisor start time and the
+ * uptime-since-hypervisor-start (in nsec.) They need to be combined
+ * in order to calculate a TOD clock.
+ */
+static int
+xen_rtc_gettime(device_t dev, struct timespec *ts)
+{
+ struct timespec w_ts, u_ts;
+
+ device_printf(dev, "[XEN] xen_rtc_gettime\n");
+ xen_fetch_wallclock(&w_ts);
+ device_printf(dev, "[XEN] xen_rtc_gettime: wallclock %ld sec; %ld nsec\n", (long int) w_ts.tv_sec, (long int) w_ts.tv_nsec);
+ xen_fetch_uptime(&u_ts);
+ device_printf(dev, "[XEN] xen_rtc_gettime: uptime %ld sec; %ld nsec\n", (long int) u_ts.tv_sec, (long int) u_ts.tv_nsec);
+
+ timespecclear(ts);
+ timespecadd(ts, &w_ts);
+ timespecadd(ts, &u_ts);
+
+ device_printf(dev, "[XEN] xen_rtc_gettime: TOD %ld sec; %ld nsec\n", (long int) ts->tv_sec, (long int) ts->tv_nsec);
+
+ return(0);
+}
+
+static void
+xen_rtc_identify(driver_t *drv, device_t parent)
+{
+ BUS_ADD_CHILD(parent, 0, "rtc", 0);
+}
+
+static device_method_t xen_rtc_methods[] = {
+ /* Device interface */
+ DEVMETHOD(device_probe, xen_rtc_probe),
+ DEVMETHOD(device_attach, xen_rtc_attach),
+ DEVMETHOD(device_identify, xen_rtc_identify),
+
+ DEVMETHOD(device_detach, bus_generic_detach),
+ DEVMETHOD(device_shutdown, bus_generic_shutdown),
+
+ /* clock interface */
+ DEVMETHOD(clock_gettime, xen_rtc_gettime),
+ DEVMETHOD(clock_settime, xen_rtc_settime),
+
+ { 0, 0 }
+};
+
+
+static driver_t xen_rtc_driver = {
+ "rtc",
+ xen_rtc_methods,
+ 0
+};
+
+static devclass_t xen_rtc_devclass;
+
+DRIVER_MODULE(rtc, nexus, xen_rtc_driver, xen_rtc_devclass, 0, 0);
_______________________________________________
svn-src-all at freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscribe at freebsd.org"
More information about the freebsd-bugs
mailing list