[Xen-changelog] [xen-unstable] [IA64] Fix ptc.ga emulation

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Alex Williamson <alex.williamson@xxxxxx>
# Date 1176474801 21600
# Node ID c42ae7839750d685e0330f76351af8b02deabadc
# Parent  41471cc650a2380876a9bff2610297ffacf2c83d
[IA64] Fix ptc.ga emulation

ptc.ga infrequently clobbers the region register 0.

When vcpu1 purges TLBs of vcpu2 and ptc_ga_remote_func() is called
locally not via IPI (i.e. vcpu1 shares the same pcpu with vcpu2),
in ptc_ga_remote_func(),

  save vrr[0] of vcpu2
  ... => switch to vcpu2 and set a new value of vrr[0]
  restore vrr[0] of vcpu2 // the new value is lost

Windows will crash due to this issue.

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
---
 xen/arch/ia64/vmx/vmmu.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff -r 41471cc650a2 -r c42ae7839750 xen/arch/ia64/vmx/vmmu.c
--- a/xen/arch/ia64/vmx/vmmu.c  Thu Apr 12 10:30:12 2007 -0600
+++ b/xen/arch/ia64/vmx/vmmu.c  Fri Apr 13 08:33:21 2007 -0600
@@ -34,6 +34,7 @@
 #include <asm/vcpu.h>
 #include <xen/irq.h>
 #include <xen/errno.h>
+#include <xen/sched-if.h>
 
 /*
  * Get the machine page frame number in 16KB unit
@@ -613,8 +614,14 @@ again: /* Try again if VCPU has migrated
         } else if (v == vcpu) {
             vmx_vcpu_ptc_l(v, va, ps);
         } else {
-            ptc_ga_remote_func(&args);
-            if (proc != v->processor)
+            vcpu_schedule_lock_irq(v);
+            proc = v->processor;
+            if (proc == vcpu->processor)
+                ptc_ga_remote_func(&args);
+            else
+                proc = INVALID_PROCESSOR;
+            vcpu_schedule_unlock_irq(v);
+            if (proc == INVALID_PROCESSOR)
                 goto again;
         }
     }

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