[Xen-changelog] [xen master] x86/HVM: adjust IRQ (de-)assertion

[patchbot@xxxxxxx]

commit f3347f520cb4d8aa4566182b013c6758d80cbe88
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue May 21 10:12:50 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue May 21 10:12:50 2013 +0200

    x86/HVM: adjust IRQ (de-)assertion
    
    De-assertion should only happen when RTC_IRQF gets cleared, i.e. upon
    REG_C reads. Assertion should be done only when the flag transitions
    from 0 to 1.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Tested-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> (FreeBSD guest)
---
 xen/arch/x86/hvm/rtc.c |   24 +++++++++++-------------
 1 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/xen/arch/x86/hvm/rtc.c b/xen/arch/x86/hvm/rtc.c
index b728d5e..b215886 100644
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -52,23 +52,19 @@ static inline int convert_hour(RTCState *s, int hour);
 
 static void rtc_update_irq(RTCState *s)
 {
-    struct domain *d = vrtc_domain(s);
-    uint8_t irqf;
-
     ASSERT(spin_is_locked(&s->lock));
 
-    /* IRQ is raised if any source is both raised & enabled */
-    irqf = (s->hw.cmos_data[RTC_REG_B]
-            & s->hw.cmos_data[RTC_REG_C]
-            & (RTC_PF|RTC_AF|RTC_UF))
-        ? RTC_IRQF : 0;
+    if ( s->hw.cmos_data[RTC_REG_C] & RTC_IRQF )
+        return;
 
-    s->hw.cmos_data[RTC_REG_C] &= ~RTC_IRQF;
-    s->hw.cmos_data[RTC_REG_C] |= irqf;
+    /* IRQ is raised if any source is both raised & enabled */
+    if ( !(s->hw.cmos_data[RTC_REG_B] &
+           s->hw.cmos_data[RTC_REG_C] &
+           (RTC_PF | RTC_AF | RTC_UF)) )
+        return;
 
-    hvm_isa_irq_deassert(d, RTC_IRQ);
-    if ( irqf )
-        hvm_isa_irq_assert(d, RTC_IRQ);
+    s->hw.cmos_data[RTC_REG_C] |= RTC_IRQF;
+    hvm_isa_irq_assert(vrtc_domain(s), RTC_IRQ);
 }
 
 void rtc_periodic_interrupt(void *opaque)
@@ -631,6 +627,8 @@ static uint32_t rtc_ioport_read(RTCState *s, uint32_t addr)
     case RTC_REG_C:
         ret = s->hw.cmos_data[s->hw.cmos_index];
         s->hw.cmos_data[RTC_REG_C] = 0x00;
+        if ( ret & RTC_IRQF )
+            hvm_isa_irq_deassert(d, RTC_IRQ);
         rtc_update_irq(s);
         check_update_timer(s);
         alarm_timer_update(s);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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