Re: Time Skewing on Windows XP

[Suravee Suthikulanit <suravee.suthikulpanit@amd.com>]

So far, this patch allows me to get the correct timing on the XP.

Suravee

diff --git a/xen/arch/x86/hvm/rtc.c b/xen/arch/x86/hvm/rtc.c
index c1e09d8..a85af5c 100644
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -76,6 +76,15 @@ void rtc_periodic_interrupt(void *opaque)
      spin_unlock(&s->lock);
  }

+static void rtc_periodic_cb(struct vcpu *v, void *opaque)
+{
+    RTCState *s = opaque;
+
+    spin_lock(&s->lock);
+    s->hw.cmos_data[RTC_REG_C] |= RTC_PF | RTC_IRQF;
+    spin_unlock(&s->lock);
+}
+
  /* Enable/configure/disable the periodic timer based on the RTC_PIE and
   * RTC_RATE_SELECT settings */
  static void rtc_timer_update(RTCState *s)
@@ -98,7 +107,7 @@ static void rtc_timer_update(RTCState *s)
          {
              period = 1 << (period_code - 1); /* period in 32 Khz cycles */
              period = DIV_ROUND(period * 1000000000ULL, 32768); /* in ns */
-            create_periodic_time(v, &s->pt, period, period, RTC_IRQ, 
NULL, s);
+            create_periodic_time(v, &s->pt, period, period, RTC_IRQ, 
rtc_periodic_cb, s);
              break;
          }
          /* fall through */
@@ -619,7 +628,6 @@ static uint32_t rtc_ioport_read(RTCState *s, 
uint32_t addr)
          s->hw.cmos_data[RTC_REG_C] = 0x00;
          check_update_timer(s);
          alarm_timer_update(s);
-        rtc_timer_update(s);
          break;
      default:
          ret = s->hw.cmos_data[s->hw.cmos_index];
diff --git a/xen/arch/x86/hvm/vpt.c b/xen/arch/x86/hvm/vpt.c
index 46d3ec6..9c1dbfb 100644
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -259,8 +259,6 @@ int pt_update_irq(struct vcpu *v)

      if ( is_lapic )
          vlapic_set_irq(vcpu_vlapic(v), irq, 0);
-    else if ( irq == RTC_IRQ && pt_priv )
-        rtc_periodic_interrupt(pt_priv);
      else
      {
          hvm_isa_irq_deassert(v->domain, irq);