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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] Provide HVM guest RTC change notification
This patch restores the capabilities initially provided in
changeset 10010. When the RTC code was moved into the hypervisor
(a good move), the control plane lost the ability to read the
current time offset as well as to receive notification of changes
to the RTC time base by a guest. This patch reintroduces these.
Additionally, there is a small window at initialization time in
which the time offset may be set but not noticed or used. If
xc_domain_set_time_offset is called before the domain is started,
the offset won't be noticed until the next second update. An HVM
guest could read the RTC in this window and get an unintended
result. This patch closes the window.
The patch builds upon the existing change notification mechanism
provided by VIRQ_DOM_EXC. I stopped short of renaming the
releaseDomain watch to something like domainEvent as it wasn't
clear who might be relying upon the existing name. A patch for
that would be easy to create, though.
Last, the code introduced into qemu by 10010 is no longer really
connected to anything and could be removed. It's found in
tools/ioemu/patches/domain-timeoffset and can probably be excised
at some suitable point. Currently, it's relatively harmless.
Signed-off-by: Ben Thomas (ben@xxxxxxxxxxxxxxx)
--
------------------------------------------------------------------------
Ben Thomas Virtual Iron Software
bthomas@xxxxxxxxxxxxxxx Tower 1, Floor 2
978-849-1214 900 Chelmsford Street
Lowell, MA 01851
Provide notification and reading of RTC change by HVM guest
If the HVM guest changes the current date/time in the RTC, signal
this to the control plan via the DOM_EXC virq. Allow the control
plane to obtain the new time via a a new call to read the time
offset for a specific domain.
Close initial condition window. If the offset is set before the
domain starts, it may not be used until after the first second
update. This leaves a small hole in which the wrong values could
be read.
Signed-off-by: Ben Thomas (ben@xxxxxxxxxxxxxxx)
diff -r 9646036c745d tools/libxc/xc_domain.c
--- a/tools/libxc/xc_domain.c Mon Mar 19 15:00:30 2007 -0400
+++ b/tools/libxc/xc_domain.c Tue Mar 20 10:55:51 2007 -0400
@@ -180,6 +180,7 @@ int xc_domain_getinfo(int xc_handle,
info->blocked = !!(domctl.u.getdomaininfo.flags&XEN_DOMINF_blocked);
info->running = !!(domctl.u.getdomaininfo.flags&XEN_DOMINF_running);
info->hvm = !!(domctl.u.getdomaininfo.flags&XEN_DOMINF_hvm_guest);
+ info->time_chg = !!(domctl.u.getdomaininfo.flags&XEN_DOMINF_time_chg);
info->shutdown_reason =
(domctl.u.getdomaininfo.flags>>XEN_DOMINF_shutdownshift) &
@@ -425,6 +426,26 @@ int xc_domain_set_time_offset(int xc_han
domctl.domain = (domid_t)domid;
domctl.u.settimeoffset.time_offset_seconds = time_offset_seconds;
return do_domctl(xc_handle, &domctl);
+}
+
+int xc_domain_get_time_offset(int xc_handle,
+ uint32_t domid,
+ int32_t *time_offset_seconds)
+{
+ int rc;
+ DECLARE_DOMCTL;
+
+ if (time_offset_seconds == NULL)
+ return -EINVAL;
+
+ domctl.cmd = XEN_DOMCTL_gettimeoffset;
+ domctl.domain = (domid_t)domid;
+
+ rc = do_domctl(xc_handle, &domctl);
+
+ *time_offset_seconds = domctl.u.gettimeoffset.time_offset_seconds;
+
+ return rc;
}
int xc_domain_memory_increase_reservation(int xc_handle,
diff -r 9646036c745d tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h Mon Mar 19 15:00:30 2007 -0400
+++ b/tools/libxc/xenctrl.h Mon Mar 19 15:01:11 2007 -0400
@@ -150,7 +150,7 @@ typedef struct xc_dominfo {
uint32_t ssidref;
unsigned int dying:1, crashed:1, shutdown:1,
paused:1, blocked:1, running:1,
- hvm:1;
+ hvm:1, time_chg:1;
unsigned int shutdown_reason; /* only meaningful if shutdown==1 */
unsigned long nr_pages;
unsigned long shared_info_frame;
@@ -487,6 +487,10 @@ int xc_domain_set_time_offset(int xc_han
int xc_domain_set_time_offset(int xc_handle,
uint32_t domid,
int32_t time_offset_seconds);
+
+int xc_domain_get_time_offset(int xc_handle,
+ uint32_t domid,
+ int32_t *time_offset_seconds);
int xc_domain_memory_increase_reservation(int xc_handle,
uint32_t domid,
diff -r 9646036c745d tools/xenstore/xenstored_domain.c
--- a/tools/xenstore/xenstored_domain.c Mon Mar 19 15:00:30 2007 -0400
+++ b/tools/xenstore/xenstored_domain.c Mon Mar 19 15:10:42 2007 -0400
@@ -195,6 +195,8 @@ static void domain_cleanup(void)
domain->shutdown = 1;
notify = 1;
}
+ if (dominfo.time_chg)
+ notify = 1;
if (!dominfo.dying)
continue;
}
diff -r 9646036c745d xen/arch/x86/hvm/rtc.c
--- a/xen/arch/x86/hvm/rtc.c Mon Mar 19 15:00:30 2007 -0400
+++ b/xen/arch/x86/hvm/rtc.c Tue Mar 20 13:16:20 2007 -0400
@@ -27,8 +27,24 @@
#include <asm/hvm/io.h>
#include <asm/hvm/support.h>
#include <asm/current.h>
+#include <xen/event.h>
/* #define DEBUG_RTC */
+
+/* Nonzero if YEAR is a leap year */
+#define __isleap(year) \
+ ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
+
+/* How many days are in each month. */
+static const unsigned short int __mon_lengths[2][12] = {
+ /* Normal years. */
+ {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+ /* Leap years. */
+ {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
+};
+
+static void rtc_copy_date(RTCState *s);
+static unsigned long RTC_mktime(struct tm *tbuf);
void rtc_periodic_cb(struct vcpu *v, void *opaque)
{
@@ -73,6 +89,13 @@ static int rtc_ioport_write(void *opaque
static int rtc_ioport_write(void *opaque, uint32_t addr, uint32_t data)
{
RTCState *s = opaque;
+
+ /* Before the first write, make sure we're completely initialized */
+ if ( unlikely(!s->accessed) )
+ {
+ rtc_copy_date(s);
+ s->accessed = 1;
+ }
if ( (addr & 1) == 0 )
{
@@ -157,7 +180,10 @@ static void rtc_set_time(RTCState *s)
static void rtc_set_time(RTCState *s)
{
struct tm *tm = &s->current_tm;
-
+ unsigned long new_time;
+ unsigned long current_time;
+ int32_t new_offset;
+
tm->tm_sec = from_bcd(s, s->hw.cmos_data[RTC_SECONDS]);
tm->tm_min = from_bcd(s, s->hw.cmos_data[RTC_MINUTES]);
tm->tm_hour = from_bcd(s, s->hw.cmos_data[RTC_HOURS] & 0x7f);
@@ -168,6 +194,18 @@ static void rtc_set_time(RTCState *s)
tm->tm_mday = from_bcd(s, s->hw.cmos_data[RTC_DAY_OF_MONTH]);
tm->tm_mon = from_bcd(s, s->hw.cmos_data[RTC_MONTH]) - 1;
tm->tm_year = from_bcd(s, s->hw.cmos_data[RTC_YEAR]) + 100;
+
+ current_time = get_localtime(s->pt.vcpu->domain) -
+ s->pt.vcpu->domain->time_offset_seconds;
+ new_time = RTC_mktime(tm);
+ new_offset = new_time - current_time;
+ if (new_offset != s->time_offset_seconds) {
+ s->time_offset_seconds = new_offset;
+ s->pt.vcpu->domain->time_offset_seconds = new_offset;
+ set_bit(_DOMF_time_chg, &s->pt.vcpu->domain->domain_flags);
+ send_guest_global_virq(dom0, VIRQ_DOM_EXC);
+ }
+
}
static void rtc_copy_date(RTCState *s)
@@ -328,6 +366,13 @@ static uint32_t rtc_ioport_read(void *op
if ( (addr & 1) == 0 )
return 0xff;
+ /* Before the first read, make sure we're completely initialized */
+ if ( unlikely(!s->accessed) )
+ {
+ rtc_copy_date(s);
+ s->accessed = 1;
+ }
+
switch ( s->hw.cmos_index )
{
case RTC_SECONDS:
@@ -434,7 +479,6 @@ void rtc_init(struct vcpu *v, int base)
void rtc_init(struct vcpu *v, int base)
{
RTCState *s = &v->domain->arch.hvm_domain.pl_time.vrtc;
-
s->pt.vcpu = v;
s->hw.cmos_data[RTC_REG_A] = RTC_REF_CLCK_32KHZ | 6; /* ~1kHz */
s->hw.cmos_data[RTC_REG_B] = RTC_24H;
@@ -462,3 +506,36 @@ void rtc_deinit(struct domain *d)
kill_timer(&s->second_timer);
kill_timer(&s->second_timer2);
}
+
+/* This routine returns value like mktime, but is not anywhere
+ near as rigorous. It assumes reasonable input values from the
+ RTC structures. Some structures borrowed from gmtime in time.c */
+
+static unsigned long RTC_mktime(struct tm *tbuf)
+{
+ int i;
+ unsigned long result;
+
+ if (tbuf == NULL)
+ return -1;
+
+ result = 0;
+ for (i=70; i < tbuf->tm_year; i++)
+ result += (__isleap(i+1900) ? 366 :365);
+
+ for (i = 0; i < tbuf->tm_mon; i++)
+ result += __mon_lengths[__isleap(tbuf->tm_year+1900)][i];
+
+ result += tbuf->tm_mday - 1;
+
+ result *= 24;
+ result += tbuf->tm_hour;
+
+ result *= 60;
+ result += tbuf->tm_min;
+
+ result *= 60;
+ result += tbuf->tm_sec;
+
+ return result;
+}
diff -r 9646036c745d xen/common/domctl.c
--- a/xen/common/domctl.c Mon Mar 19 15:00:30 2007 -0400
+++ b/xen/common/domctl.c Tue Mar 20 10:56:19 2007 -0400
@@ -117,6 +117,7 @@ void getdomaininfo(struct domain *d, str
((d->domain_flags & DOMF_dying) ? XEN_DOMINF_dying : 0) |
((d->domain_flags & DOMF_shutdown) ? XEN_DOMINF_shutdown : 0) |
((d->domain_flags & DOMF_ctrl_pause) ? XEN_DOMINF_paused : 0) |
+ ((d->domain_flags & DOMF_time_chg) ? XEN_DOMINF_time_chg : 0) |
d->shutdown_code << XEN_DOMINF_shutdownshift;
if ( is_hvm_domain(d) )
@@ -711,6 +712,25 @@ long do_domctl(XEN_GUEST_HANDLE(xen_domc
}
break;
+ case XEN_DOMCTL_gettimeoffset:
+ {
+ struct domain *d;
+
+ ret = -ESRCH;
+ d = rcu_lock_domain_by_id(op->domain);
+ if ( d != NULL )
+ {
+ op->u.gettimeoffset.time_offset_seconds = d->time_offset_seconds;
+ ret = 0;
+ if ( copy_to_guest(u_domctl, op, 1) )
+ ret = -EFAULT;
+
+ clear_bit(_DOMF_time_chg, &d->domain_flags);
+ rcu_unlock_domain(d);
+ }
+ }
+ break;
+
default:
ret = arch_do_domctl(op, u_domctl);
break;
diff -r 9646036c745d xen/include/asm-x86/hvm/vpt.h
--- a/xen/include/asm-x86/hvm/vpt.h Mon Mar 19 15:00:30 2007 -0400
+++ b/xen/include/asm-x86/hvm/vpt.h Tue Mar 20 11:18:22 2007 -0400
@@ -93,6 +93,7 @@ typedef struct RTCState {
struct timer second_timer2;
struct periodic_time pt;
int32_t time_offset_seconds;
+ unsigned int accessed:1;
} RTCState;
#define FREQUENCE_PMTIMER 3579545 /* Timer should run at 3.579545 MHz */
diff -r 9646036c745d xen/include/public/domctl.h
--- a/xen/include/public/domctl.h Mon Mar 19 15:00:30 2007 -0400
+++ b/xen/include/public/domctl.h Mon Mar 19 15:01:11 2007 -0400
@@ -85,6 +85,10 @@ struct xen_domctl_getdomaininfo {
/* Domain is currently running. */
#define _XEN_DOMINF_running 5
#define XEN_DOMINF_running (1U<<_XEN_DOMINF_running)
+/* Domain has a time offset change */
+#define _XEN_DOMINF_time_chg 6
+#define XEN_DOMINF_time_chg (1U<<_XEN_DOMINF_time_chg)
+
/* CPU to which this domain is bound. */
#define XEN_DOMINF_cpumask 255
#define XEN_DOMINF_cpushift 8
@@ -388,6 +392,13 @@ struct xen_domctl_settimeoffset {
};
typedef struct xen_domctl_settimeoffset xen_domctl_settimeoffset_t;
DEFINE_XEN_GUEST_HANDLE(xen_domctl_settimeoffset_t);
+
+#define XEN_DOMCTL_gettimeoffset 37
+struct xen_domctl_gettimeoffset {
+ int32_t time_offset_seconds; /* applied to domain wallclock time */
+};
+typedef struct xen_domctl_gettimeoffset xen_domctl_gettimeoffset_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_gettimeoffset_t);
#define XEN_DOMCTL_gethvmcontext 33
@@ -453,6 +464,7 @@ struct xen_domctl {
struct xen_domctl_hypercall_init hypercall_init;
struct xen_domctl_arch_setup arch_setup;
struct xen_domctl_settimeoffset settimeoffset;
+ struct xen_domctl_gettimeoffset gettimeoffset;
struct xen_domctl_real_mode_area real_mode_area;
struct xen_domctl_hvmcontext hvmcontext;
struct xen_domctl_address_size address_size;
diff -r 9646036c745d xen/include/xen/sched.h
--- a/xen/include/xen/sched.h Mon Mar 19 15:00:30 2007 -0400
+++ b/xen/include/xen/sched.h Mon Mar 19 15:01:11 2007 -0400
@@ -474,6 +474,9 @@ extern struct domain *domain_list;
/* Domain is a compatibility one? */
#define _DOMF_compat 6
#define DOMF_compat (1UL<<_DOMF_compat)
+ /* Domain time offset has changed */
+#define _DOMF_time_chg 7
+#define DOMF_time_chg (1UL<<_DOMF_time_chg)
static inline int vcpu_runnable(struct vcpu *v)
{
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