x86/vector: Respect affinity mask in irq descriptor

The interrupt descriptor has a preset affinity mask at allocation
time, which is usually the default affinity mask.

The current code does not respect that mask and places the vector at some
random CPU, which gets corrected later by a set_affinity() call. That's
silly because the vector allocation can respect the mask upfront and place
the interrupt on a CPU which is in the mask. If that fails, then the
affinity is broken and a interrupt assigned on any online CPU.

Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Juergen Gross <[email protected]>
Tested-by: Yu Chen <[email protected]>
Acked-by: Juergen Gross <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Alok Kataria <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Rui Zhang <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Len Brown <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

1 files changed, 17 insertions, 4 deletions

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 14b21ca4483c..6789e286def9 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -249,12 +249,25 @@ static int assign_irq_vector(struct irq_data *irqd, const struct cpumask *dest)
 
 static int assign_irq_vector_any_locked(struct irq_data *irqd)
 {
+	/* Get the affinity mask - either irq_default_affinity or (user) set */
+	const struct cpumask *affmsk = irq_data_get_affinity_mask(irqd);
 	int node = irq_data_get_node(irqd);
 
-	if (node != NUMA_NO_NODE) {
-		if (!assign_vector_locked(irqd, cpumask_of_node(node)))
-			return 0;
-	}
+	if (node == NUMA_NO_NODE)
+		goto all;
+	/* Try the intersection of @affmsk and node mask */
+	cpumask_and(vector_searchmask, cpumask_of_node(node), affmsk);
+	if (!assign_vector_locked(irqd, vector_searchmask))
+		return 0;
+	/* Try the node mask */
+	if (!assign_vector_locked(irqd, cpumask_of_node(node)))
+		return 0;
+all:
+	/* Try the full affinity mask */
+	cpumask_and(vector_searchmask, affmsk, cpu_online_mask);
+	if (!assign_vector_locked(irqd, vector_searchmask))
+		return 0;
+	/* Try the full online mask */
 	return assign_vector_locked(irqd, cpu_online_mask);
 }