x86: fix cpu_mask_to_apicid_and to include cpu_online_mask

Impact: fix potential APIC crash

In determining the destination apicid, there are usually three cpumasks
that are considered: the incoming cpumask arg, cfg->domain and the
cpu_online_mask.  Since we are just introducing the cpu_mask_to_apicid_and
function, make sure it includes the cpu_online_mask in it's evaluation.
[Added with this patch.]

There are two io_apic.c functions that did not previously use the
cpu_online_mask:  setup_IO_APIC_irq and msi_compose_msg.  Both of these
simply used cpu_mask_to_apicid(cfg->domain & TARGET_CPUS), and all but
one arch (NUMAQ[*]) returns only online cpus in the TARGET_CPUS mask,
so the behavior is identical for all cases.

[*: NUMAQ bug?]

Note that alloc_cpumask_var is only used for the 32-bit cases where
it's highly likely that the cpumask set size will be small and therefore
CPUMASK_OFFSTACK=n.  But if that's not the case, failing the allocate
will cause the same return value as the default.

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/kernel/genapic_flat_64.c b/arch/x86/kernel/genapic_flat_64.c
index 7fa5f49c2dd..34185488e4f 100644
--- a/arch/x86/kernel/genapic_flat_64.c
+++ b/arch/x86/kernel/genapic_flat_64.c
@@ -276,7 +276,9 @@ physflat_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
 	 * We're using fixed IRQ delivery, can only return one phys APIC ID.
 	 * May as well be the first.
 	 */
-	cpu = cpumask_any_and(cpumask, andmask);
+	for_each_cpu_and(cpu, cpumask, andmask)
+		if (cpumask_test_cpu(cpu, cpu_online_mask))
+			break;
 	if (cpu < nr_cpu_ids)
 		return per_cpu(x86_cpu_to_apicid, cpu);
 	return BAD_APICID;