[Xen-devel] [PATCH] x86/IRQ: eliminate irq_vector[]

["Jan Beulich" <JBeulich@xxxxxxxx>]

The vector is already being tracked in struct irq_desc's arch.vector
member, so there's no real need for a second place where this to get
stored. The only caveat is that legacy vectors (used for interrupts
handled through the 8259) must be special cased to not prevent non-
legacy vectors from being assigned.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -452,10 +452,10 @@ static void unmask_IO_APIC_irq(struct ir
     spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
-static void __eoi_IO_APIC_irq(unsigned int irq)
+static void __eoi_IO_APIC_irq(struct irq_desc *desc)
 {
-    struct irq_pin_list *entry = irq_2_pin + irq;
-    unsigned int pin, vector = IO_APIC_VECTOR(irq);
+    struct irq_pin_list *entry = irq_2_pin + desc->irq;
+    unsigned int pin, vector = desc->arch.vector;
 
     for (;;) {
         pin = entry->pin;
@@ -468,11 +468,11 @@ static void __eoi_IO_APIC_irq(unsigned i
     }
 }
 
-static void eoi_IO_APIC_irq(unsigned int irq)
+static void eoi_IO_APIC_irq(struct irq_desc *desc)
 {
     unsigned long flags;
     spin_lock_irqsave(&ioapic_lock, flags);
-    __eoi_IO_APIC_irq(irq);
+    __eoi_IO_APIC_irq(desc);
     spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
@@ -1200,7 +1200,7 @@ static void /*__init*/ __print_IO_APIC(v
         struct irq_pin_list *entry = irq_2_pin + i;
         if (entry->pin < 0)
             continue;
-        printk(KERN_DEBUG "IRQ%d ", IO_APIC_VECTOR(i));
+        printk(KERN_DEBUG "IRQ%d ", irq_to_desc(i)->arch.vector);
         for (;;) {
             printk("-> %d:%d", entry->apic, entry->pin);
             if (!entry->next)
@@ -1621,7 +1621,7 @@ static void mask_and_ack_level_ioapic_ir
  * operation to prevent an edge-triggered interrupt escaping meanwhile.
  * The idea is from Manfred Spraul.  --macro
  */
-    i = IO_APIC_VECTOR(desc->irq);
+    i = desc->arch.vector;
 
     v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));
 
@@ -1653,12 +1653,12 @@ static void end_level_ioapic_irq(struct 
         {
             if ( !(desc->status & (IRQ_DISABLED|IRQ_MOVE_PENDING)) )
             {
-                eoi_IO_APIC_irq(desc->irq);
+                eoi_IO_APIC_irq(desc);
                 return;
             }
 
             mask_IO_APIC_irq(desc);
-            eoi_IO_APIC_irq(desc->irq);
+            eoi_IO_APIC_irq(desc);
             if ( (desc->status & IRQ_MOVE_PENDING) &&
                  !io_apic_level_ack_pending(desc->irq) )
                 move_masked_irq(desc);
@@ -1689,7 +1689,7 @@ static void end_level_ioapic_irq(struct 
  * operation to prevent an edge-triggered interrupt escaping meanwhile.
  * The idea is from Manfred Spraul.  --macro
  */
-    i = IO_APIC_VECTOR(desc->irq);
+    i = desc->arch.vector;
 
     /* Manually EOI the old vector if we are moving to the new */
     if ( vector && i != vector )
@@ -1752,7 +1752,7 @@ static inline void init_IO_APIC_traps(vo
     int irq;
     /* Xen: This is way simpler than the Linux implementation. */
     for (irq = 0; platform_legacy_irq(irq); irq++)
-        if (IO_APIC_IRQ(irq) && !IO_APIC_VECTOR(irq))
+        if (IO_APIC_IRQ(irq) && !irq_to_vector(irq))
             make_8259A_irq(irq);
 }
 
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -41,7 +41,6 @@ custom_param("irq_vector_map", parse_irq
 
 vmask_t global_used_vector_map;
 
-u8 __read_mostly *irq_vector;
 struct irq_desc __read_mostly *irq_desc = NULL;
 
 static DECLARE_BITMAP(used_vectors, NR_VECTORS);
@@ -135,8 +134,6 @@ static int __init __bind_irq_vector(int 
         set_bit(vector, desc->arch.used_vectors);
     }
     desc->arch.used = IRQ_USED;
-    if (IO_APIC_IRQ(irq))
-        irq_vector[irq] = vector;
     return 0;
 }
 
@@ -289,7 +286,11 @@ int irq_to_vector(int irq)
     BUG_ON(irq >= nr_irqs || irq < 0);
 
     if (IO_APIC_IRQ(irq))
-        vector = irq_vector[irq];
+    {
+        vector = irq_to_desc(irq)->arch.vector;
+        if (vector >= FIRST_LEGACY_VECTOR && vector <= LAST_LEGACY_VECTOR)
+            vector = 0;
+    }
     else if (MSI_IRQ(irq))
         vector = irq_to_desc(irq)->arch.vector;
     else
@@ -331,9 +332,8 @@ int __init init_irq_data(void)
         this_cpu(vector_irq)[vector] = -1;
 
     irq_desc = xzalloc_array(struct irq_desc, nr_irqs);
-    irq_vector = xzalloc_array(u8, nr_irqs_gsi);
     
-    if ( !irq_desc || !irq_vector )
+    if ( !irq_desc )
         return -ENOMEM;
 
     for (irq = 0; irq < nr_irqs_gsi; irq++) {
@@ -426,7 +426,7 @@ static int __assign_irq_vector(
     vmask_t *irq_used_vectors = NULL;
 
     old_vector = irq_to_vector(irq);
-    if (old_vector) {
+    if (old_vector > 0) {
         cpumask_and(&tmp_mask, mask, &cpu_online_map);
         if (cpumask_intersects(&tmp_mask, desc->arch.cpu_mask)) {
             desc->arch.vector = old_vector;
@@ -485,7 +485,7 @@ next:
         /* Found one! */
         current_vector = vector;
         current_offset = offset;
-        if (old_vector) {
+        if (old_vector > 0) {
             desc->arch.move_in_progress = 1;
             cpumask_copy(desc->arch.old_cpu_mask, desc->arch.cpu_mask);
             desc->arch.old_vector = desc->arch.vector;
@@ -501,9 +501,6 @@ next:
                || (desc->arch.used_vectors == irq_used_vectors));
         desc->arch.used_vectors = irq_used_vectors;
 
-        if (IO_APIC_IRQ(irq))
-            irq_vector[irq] = vector;
-
         if ( desc->arch.used_vectors )
         {
             ASSERT(!test_bit(vector, desc->arch.used_vectors));
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -998,7 +998,7 @@ void __init smp_intr_init(void)
      * IRQ0 must be given a fixed assignment and initialized,
      * because it's used before the IO-APIC is set up.
      */
-    irq_vector[0] = FIRST_HIPRIORITY_VECTOR;
+    irq_to_desc(0)->arch.vector = FIRST_HIPRIORITY_VECTOR;
 
     /*
      * Also ensure serial interrupts are high priority. We do not
@@ -1008,7 +1008,6 @@ void __init smp_intr_init(void)
     {
         if ( (irq = serial_irq(seridx)) < 0 )
             continue;
-        irq_vector[irq] = FIRST_HIPRIORITY_VECTOR + seridx + 1;
         per_cpu(vector_irq, cpu)[FIRST_HIPRIORITY_VECTOR + seridx + 1] = irq;
         irq_to_desc(irq)->arch.vector = FIRST_HIPRIORITY_VECTOR + seridx + 1;
         cpumask_copy(irq_to_desc(irq)->arch.cpu_mask, &cpu_online_map);
--- a/xen/include/asm-x86/irq.h
+++ b/xen/include/asm-x86/irq.h
@@ -14,7 +14,6 @@
 #define IO_APIC_IRQ(irq)    (platform_legacy_irq(irq) ?    \
                             (1 << (irq)) & io_apic_irqs : \
                             (irq) < nr_irqs_gsi)
-#define IO_APIC_VECTOR(irq) (irq_vector[irq])
 
 #define MSI_IRQ(irq)       ((irq) >= nr_irqs_gsi && (irq) < nr_irqs)
 
@@ -48,8 +47,6 @@ struct arch_irq_desc {
 typedef int vector_irq_t[NR_VECTORS];
 DECLARE_PER_CPU(vector_irq_t, vector_irq);
 
-extern u8 *irq_vector;
-
 extern bool_t opt_noirqbalance;
 
 #define OPT_IRQ_VECTOR_MAP_DEFAULT 0 /* Do the default thing  */

Attachment: x86-no-irq_vector.patch
Description: Text document

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