x86, apic: Cleanup cfg->domain setup for legacy interrupts

Issues that need to be handled:
* Handle PIC interrupts on any CPU irrespective of the apic mode
* In the apic lowest priority logical flat delivery mode, be prepared to
  handle the interrupt on any CPU irrespective of what the IO-APIC RTE says.
* Because of above, when the IO-APIC starts handling the legacy PIC interrupt,
  use the same vector that is being used by the PIC while programming the
  corresponding IO-APIC RTE.

Start with all the cpu's in the legacy PIC interrupts cfg->domain.

By the time IO-APIC starts taking over the PIC interrupts, apic driver
model is finalized. So depend on the assign_irq_vector() to update the
cfg->domain and retain the same vector that was used by PIC before.

For the logical apic flat mode, cfg->domain is updated (during the first
call to assign_irq_vector()) to contain all the possible online cpu's (0xff).
Vector used for the legacy PIC interrupt doesn't change when the IO-APIC
starts handling the interrupt. Any interrupt migration after that
doesn't change the cfg->domain or the vector used.

For other apic modes like physical mode, cfg->domain is updated
(during the first call to assign_irq_vector()) to the boot cpu (cpu-0),
with the same vector that is being used by the PIC. When that interrupt is
migrated to a different cpu, cfg->domin and the vector assigned will change
accordingly.

Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1353970176.21070.51.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 6 insertions, 20 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index c265593ec2cd..0c1f36650568 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -234,11 +234,11 @@ int __init arch_early_irq_init(void)
                 zalloc_cpumask_var_node(&cfg[i].old_domain, GFP_KERNEL, node);
                 /*
                  * For legacy IRQ's, start with assigning irq0 to irq15 to
-                 * IRQ0_VECTOR to IRQ15_VECTOR on cpu 0.
+                 * IRQ0_VECTOR to IRQ15_VECTOR for all cpu's.
                  */
                 if (i < legacy_pic->nr_legacy_irqs) {
                         cfg[i].vector = IRQ0_VECTOR + i;
-                        cpumask_set_cpu(0, cfg[i].domain);
+                        cpumask_setall(cfg[i].domain);
                 }
         }
 
@@ -1141,7 +1141,8 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
                          * allocation for the members that are not used anymore.
                          */
                         cpumask_andnot(cfg->old_domain, cfg->domain, tmp_mask);
-                        cfg->move_in_progress = 1;
+                        cfg->move_in_progress =
+                           cpumask_intersects(cfg->old_domain, cpu_online_mask);
                         cpumask_and(cfg->domain, cfg->domain, tmp_mask);
                         break;
                 }
@@ -1172,8 +1173,9 @@ next:
                 current_vector = vector;
                 current_offset = offset;
                 if (cfg->vector) {
-                        cfg->move_in_progress = 1;
                         cpumask_copy(cfg->old_domain, cfg->domain);
+                        cfg->move_in_progress =
+                           cpumask_intersects(cfg->old_domain, cpu_online_mask);
                 }
                 for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask)
                         per_cpu(vector_irq, new_cpu)[vector] = irq;
@@ -1241,12 +1243,6 @@ void __setup_vector_irq(int cpu)
                 cfg = irq_get_chip_data(irq);
                 if (!cfg)
                         continue;
-                /*
-                 * If it is a legacy IRQ handled by the legacy PIC, this cpu
-                 * will be part of the irq_cfg's domain.
-                 */
-                if (irq < legacy_pic->nr_legacy_irqs && !IO_APIC_IRQ(irq))
-                        cpumask_set_cpu(cpu, cfg->domain);
 
                 if (!cpumask_test_cpu(cpu, cfg->domain))
                         continue;
@@ -1356,16 +1352,6 @@ static void setup_ioapic_irq(unsigned int irq, struct irq_cfg *cfg,
         if (!IO_APIC_IRQ(irq))
                 return;
 
-        /*
-         * For legacy irqs, cfg->domain starts with cpu 0. Now that IO-APIC
-         * can handle this irq and the apic driver is finialized at this point,
-         * update the cfg->domain.
-         */
-        if (irq < legacy_pic->nr_legacy_irqs &&
-            cpumask_equal(cfg->domain, cpumask_of(0)))
-                apic->vector_allocation_domain(0, cfg->domain,
-                                               apic->target_cpus());
-
         if (assign_irq_vector(irq, cfg, apic->target_cpus()))
                 return;