[PATCH v2 for-4.21 8/9] x86/HPET: don't use hardcoded 0 for "long timeout"

[Jan Beulich]

With 32-bit counters, writing 0 means on average half the wrapping period
until an interrupt would be raised. Yet of course in extreme cases an
interrupt would be raised almost right away. Write the present counter
value instead, to make the timeout predicatbly a full wrapping period.

Fixes: e862b83e8433 ("CPUIDLE: Avoid remnant HPET intr while force 
hpetbroadcast")
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
Actually - can't we just disable the channel instead of setting a "long"
timeout? Of course we'd then also need to enable it a few lines down. Yet
in turn we could then remove the enabling from set_channel_irq_affinity().

--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -165,7 +165,7 @@ static int reprogram_hpet_evt_channel(
     if ( expire == STIME_MAX )
     {
         /* We assume it will take a long time for the timer to wrap. */
-        hpet_write32(0, HPET_Tn_CMP(ch->idx));
+        hpet_write32(hpet_read32(HPET_COUNTER), HPET_Tn_CMP(ch->idx));
         return 0;
     }