Xen devel - Jan 2010 - [PATCH]x86: fix unmaskable msi assignment issue

x86: fix unmaskable msi assignment issue.
 
Currently, unmasked msi irq''s EOI write is deferred untile guest writes
EOI, so
needs to keep eoi_vector unchanged before guest writes EOI. However, irq
migration
breaks the assumption and changs eoi_vector when interrupts are generated
through
new vector. 
 
The patch removes the dependency for eoi_vector and directly recoreds the irq
info
in the EOI stack, and when guest writes EOI, just do the physical EOI for the 
specific irq(recorded in EOI stack)on the cpus according to the cpu_eoi_map.
 
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
 

diff -r 596f7893b5ac xen/arch/x86/irq.c
--- a/xen/arch/x86/irq.c Sat Jan 09 08:14:44 2010 +0000
+++ b/xen/arch/x86/irq.c Tue Jan 12 22:04:00 2010 +0800
@@ -740,7 +740,6 @@ typedef struct {
 #define ACKTYPE_UNMASK 1     /* Unmask PIC hardware (from any CPU)   */
 #define ACKTYPE_EOI    2     /* EOI on the CPU that was interrupted  */
     cpumask_t cpu_eoi_map;   /* CPUs that need to EOI this interrupt */
-    u8 eoi_vector;           /* vector awaiting the EOI*/
     struct domain *guest[IRQ_MAX_GUESTS];
 } irq_guest_action_t;
 
@@ -749,8 +748,9 @@ typedef struct {
  * order, as only the current highest-priority pending irq can be EOIed.
  */
 struct pending_eoi {
-    u8 vector; /* vector awaiting EOI */
-    u8 ready;  /* Ready for EOI now?  */
+    u32 ready:1;  /* Ready for EOI now?  */
+    u32 irq:23;   /* irq of the vector */
+    u32 vector:8; /* vector awaiting EOI */
 };
 
 static DEFINE_PER_CPU(struct pending_eoi, pending_eoi[NR_VECTORS]);
@@ -817,11 +817,11 @@ static void __do_IRQ_guest(int irq)
         sp = pending_eoi_sp(peoi);
         ASSERT((sp == 0) || (peoi[sp-1].vector < vector));
         ASSERT(sp < (NR_VECTORS-1));
+        peoi[sp].irq = irq;
         peoi[sp].vector = vector;
         peoi[sp].ready = 0;
         pending_eoi_sp(peoi) = sp+1;
         cpu_set(smp_processor_id(), action->cpu_eoi_map);
-        action->eoi_vector = vector;
     }
 
     for ( i = 0; i < action->nr_guests; i++ )
@@ -913,7 +913,7 @@ static void flush_ready_eoi(void)
 
     while ( (--sp >= 0) && peoi[sp].ready )
     {
-        irq = __get_cpu_var(vector_irq[peoi[sp].vector]);
+        irq = peoi[sp].irq;
         ASSERT(irq > 0);
         desc = irq_to_desc(irq);
         spin_lock(&desc->lock);
@@ -941,7 +941,7 @@ static void __set_eoi_ready(struct irq_d
 
     do {
         ASSERT(sp > 0);
-    } while ( peoi[--sp].vector != action->eoi_vector );
+    } while ( peoi[--sp].irq != irq );
     ASSERT(!peoi[sp].ready);
     peoi[sp].ready = 1;
 }



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