[Xen-devel] [PATCH 1 of 3] xen: Infrastructure to allow irqs to share vector maps

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

Laying the groundwork for per-device vector maps.  This generic
code allows any irq to point to a vector map; all irqs sharing the
same vector map will avoid sharing vectors.

Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

diff -r e8d1c8f074ba -r 4c8f3cae5007 xen/arch/x86/io_apic.c
--- a/xen/arch/x86/io_apic.c    Mon Jul 25 16:43:26 2011 +0100
+++ b/xen/arch/x86/io_apic.c    Tue Jul 26 17:21:23 2011 +0100
@@ -449,6 +449,11 @@ fastcall void smp_irq_move_cleanup_inter
                  irq, vector, smp_processor_id());
 
         __get_cpu_var(vector_irq)[vector] = -1;
+        if ( cfg->used_vectors )
+        {
+            ASSERT(test_bit(vector, cfg->used_vectors));
+            clear_bit(vector, cfg->used_vectors);
+        }
         cfg->move_cleanup_count--;
 unlock:
         spin_unlock(&desc->lock);
diff -r e8d1c8f074ba -r 4c8f3cae5007 xen/arch/x86/irq.c
--- a/xen/arch/x86/irq.c        Mon Jul 25 16:43:26 2011 +0100
+++ b/xen/arch/x86/irq.c        Tue Jul 26 17:21:23 2011 +0100
@@ -108,6 +108,8 @@ static int __init __bind_irq_vector(int 
         per_cpu(vector_irq, cpu)[vector] = irq;
     cfg->vector = vector;
     cfg->cpu_mask = online_mask;
+    if ( cfg->used_vectors )
+        set_bit(vector, cfg->used_vectors);
     irq_status[irq] = IRQ_USED;
     if (IO_APIC_IRQ(irq))
         irq_vector[irq] = vector;
@@ -172,6 +174,7 @@ static void dynamic_irq_cleanup(unsigned
     desc->depth   = 1;
     desc->msi_desc = NULL;
     desc->handler = &no_irq_type;
+    desc->chip_data->used_vectors=NULL;
     cpus_setall(desc->affinity);
     spin_unlock_irqrestore(&desc->lock, flags);
 
@@ -200,6 +203,9 @@ static void __clear_irq_vector(int irq)
     for_each_cpu_mask(cpu, tmp_mask)
         per_cpu(vector_irq, cpu)[vector] = -1;
 
+    if ( cfg->used_vectors )
+        clear_bit(vector, cfg->used_vectors);
+
     cfg->vector = IRQ_VECTOR_UNASSIGNED;
     cpus_clear(cfg->cpu_mask);
     init_one_irq_status(irq);
@@ -277,6 +283,7 @@ static void __init init_one_irq_cfg(stru
     cfg->vector = IRQ_VECTOR_UNASSIGNED;
     cpus_clear(cfg->cpu_mask);
     cpus_clear(cfg->old_cpu_mask);
+    cfg->used_vectors = NULL;
 }
 
 int __init init_irq_data(void)
@@ -402,6 +409,10 @@ next:
         if (test_bit(vector, used_vectors))
             goto next;
 
+        if (cfg->used_vectors
+            && test_bit(vector, cfg->used_vectors) )
+            goto next;
+
         for_each_cpu_mask(new_cpu, tmp_mask)
             if (per_cpu(vector_irq, new_cpu)[vector] != -1)
                 goto next;
@@ -417,6 +428,11 @@ next:
             per_cpu(vector_irq, new_cpu)[vector] = irq;
         cfg->vector = vector;
         cpus_copy(cfg->cpu_mask, tmp_mask);
+        if ( cfg->used_vectors )
+        {
+            ASSERT(!test_bit(vector, cfg->used_vectors));
+            set_bit(vector, cfg->used_vectors);
+        }
 
         irq_status[irq] = IRQ_USED;
             if (IO_APIC_IRQ(irq))
diff -r e8d1c8f074ba -r 4c8f3cae5007 xen/include/asm-x86/irq.h
--- a/xen/include/asm-x86/irq.h Mon Jul 25 16:43:26 2011 +0100
+++ b/xen/include/asm-x86/irq.h Tue Jul 26 17:21:23 2011 +0100
@@ -24,11 +24,16 @@
 #define irq_to_desc(irq)    (&irq_desc[irq])
 #define irq_cfg(irq)        (&irq_cfg[irq])
 
+typedef struct {
+    DECLARE_BITMAP(_bits,NR_VECTORS);
+} vmask_t;
+
 struct irq_cfg {
         int  vector;
         cpumask_t cpu_mask;
         cpumask_t old_cpu_mask;
         unsigned move_cleanup_count;
+        vmask_t *used_vectors;
         u8 move_in_progress : 1;
 };
 

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