[xen staging] x86/vhpet: fix RTC special casing

[patchbot@xxxxxxx]

commit 472a13988a051e5ae84b95815c6caf4378062abe
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Fri May 7 10:43:29 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri May 7 10:43:29 2021 +0200

    x86/vhpet: fix RTC special casing
    
    Restore setting the virtual timer callback private data to NULL if the
    timer is not level triggered. This fixes the special casing done in
    pt_update_irq so that the RTC interrupt when originating from the HPET
    is suspended if the interrupt source is masked.
    
    Note the RTC special casing done in pt_update_irq should only apply to
    the RTC interrupt originating from the emulated RTC device (which does
    set the callback private data), as in that case the callback itself
    will destroy the virtual timer if the interrupt is ignored.
    
    While there also use RTC_IRQ instead of 8 when the HPET is configured
    in LegacyReplacement Mode.
    
    Fixes: be07023be115 ("x86/vhpet: add support for level triggered 
interrupts")
    Reported-by: Jan Beulich <jbeulich@xxxxxxxx>
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/hpet.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
index ca94e8b453..ee756abb82 100644
--- a/xen/arch/x86/hvm/hpet.c
+++ b/xen/arch/x86/hvm/hpet.c
@@ -22,6 +22,7 @@
 #include <asm/hvm/trace.h>
 #include <asm/current.h>
 #include <asm/hpet.h>
+#include <asm/mc146818rtc.h>
 #include <xen/sched.h>
 #include <xen/event.h>
 #include <xen/trace.h>
@@ -290,7 +291,7 @@ static void hpet_set_timer(HPETState *h, unsigned int tn,
         /* if LegacyReplacementRoute bit is set, HPET specification requires
            timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
            timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC. */
-        irq = (tn == 0) ? 0 : 8;
+        irq = (tn == 0) ? 0 : RTC_IRQ;
         h->pt[tn].source = PTSRC_isa;
     }
     else
@@ -318,7 +319,8 @@ static void hpet_set_timer(HPETState *h, unsigned int tn,
                          hpet_tick_to_ns(h, diff),
                          oneshot ? 0 : hpet_tick_to_ns(h, h->hpet.period[tn]),
                          irq, timer_level(h, tn) ? hpet_timer_fired : NULL,
-                         (void *)(unsigned long)tn, timer_level(h, tn));
+                         timer_level(h, tn) ? (void *)(unsigned long)tn : NULL,
+                         timer_level(h, tn));
 }
 
 static inline uint64_t hpet_fixup_reg(
--
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