IRQ: Introduce old_vector to irq_cfg

Introduce old_vector to irq_cfg with the same principle as
old_cpu_mask.  This removes a brute force loop from
__clear_irq_vector(), and paves the way to correct bitrotten logic
elsewhere in the irq code.

Signed-off-by Andrew Cooper <andrew.cooper3@citrix.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c
index 0fdcc7d694..bccd52be8e 100644
--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -488,11 +488,16 @@ fastcall void smp_irq_move_cleanup_interrupt(struct cpu_user_regs *regs)
         __get_cpu_var(vector_irq)[vector] = -1;
         cfg->move_cleanup_count--;
 
-        if ( cfg->move_cleanup_count == 0 
-             &&  cfg->used_vectors )
+        if ( cfg->move_cleanup_count == 0 )
         {
-            ASSERT(test_bit(vector, cfg->used_vectors));
-            clear_bit(vector, cfg->used_vectors);
+            cfg->old_vector = IRQ_VECTOR_UNASSIGNED;
+            cpus_clear(cfg->old_cpu_mask);
+
+            if ( cfg->used_vectors )
+            {
+                ASSERT(test_bit(vector, cfg->used_vectors));
+                clear_bit(vector, cfg->used_vectors);
+            }
         }
 unlock:
         spin_unlock(&desc->lock);