[Xen-changelog] [xen stable-4.2] x86: irq_move_cleanup_interrupt() must ignore legacy vectors

[patchbot@xxxxxxx]

commit 5da556675105169807ae2bfe232a2cc4c3f2ae1e
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 9 16:04:25 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 9 16:04:25 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>
    master commit: af699220ad6d111ba76fc3040342184e423cc9a1
    master date: 2013-04-02 08:30:03 +0200
---
 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 9cfbca8..1ff2a8c 100644
--- a/xen/arch/x86/i8259.c
+++ b/xen/arch/x86/i8259.c
@@ -406,6 +406,8 @@ 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 0964c76..5833612 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 (irq == -1)
             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#stable-4.2

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