[Xen-changelog] [xen master] x86: irq_move_cleanup_interrupt() must ignore legacy vectors

[patchbot@xxxxxxx]

commit af699220ad6d111ba76fc3040342184e423cc9a1
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 2 08:30:03 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 2 08:30:03 2013 +0200

    x86: irq_move_cleanup_interrupt() must ignore legacy vectors
    
    Since the main loop in the function includes legacy vectors, and since
    vector_irq[] gets set up for legacy vectors regardless of whether those
    get handled through the IO-APIC, it must not do anything on this vector
    range. In fact, we should never get past the move_cleanup_count check
    for IRQs not handled through the IO-APIC. Adding a respective assertion
    woulkd make those iterations more expensive (due to the lock acquire).
    
    For such an assertion to not have false positives we however ought to
    suppress setting up IRQ2 as an 8259A interrupt (which wasn't correct
    anyway), which is being done here despite the assertion not actually
    getting added.
    
    Furthermore, there's no point iterating over the vectors past
    LAST_HIPRIORITY_VECTOR, so terminate the loop accordingly.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
---
 xen/arch/x86/i8259.c |    2 ++
 xen/arch/x86/irq.c   |    7 ++++++-
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/i8259.c b/xen/arch/x86/i8259.c
index f637ecc..b537c5f 100644
--- a/xen/arch/x86/i8259.c
+++ b/xen/arch/x86/i8259.c
@@ -416,6 +416,8 @@ void __init init_IRQ(void)
     for (irq = 0; platform_legacy_irq(irq); irq++) {
         struct irq_desc *desc = irq_to_desc(irq);
         
+        if ( irq == 2 ) /* IRQ2 doesn't exist */
+            continue;
         desc->handler = &i8259A_irq_type;
         per_cpu(vector_irq, cpu)[FIRST_LEGACY_VECTOR + irq] = irq;
         cpumask_copy(desc->arch.cpu_mask, cpumask_of(cpu));
diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 5e0f463..fff9f1d 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -616,7 +616,9 @@ void irq_move_cleanup_interrupt(struct cpu_user_regs *regs)
     ack_APIC_irq();
 
     me = smp_processor_id();
-    for (vector = FIRST_DYNAMIC_VECTOR; vector < NR_VECTORS; vector++) {
+    for ( vector = FIRST_DYNAMIC_VECTOR;
+          vector <= LAST_HIPRIORITY_VECTOR; vector++)
+    {
         unsigned int irq;
         unsigned int irr;
         struct irq_desc *desc;
@@ -625,6 +627,9 @@ void irq_move_cleanup_interrupt(struct cpu_user_regs *regs)
         if ((int)irq < 0)
             continue;
 
+        if ( vector >= FIRST_LEGACY_VECTOR && vector <= LAST_LEGACY_VECTOR )
+            continue;
+
         desc = irq_to_desc(irq);
         if (!desc)
             continue;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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