Merge tag 'irq-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Thomas Gleixner:

 - Fix an off-by-one error in the failure path of msi_domain_alloc(),
   which causes the cleanup loop to terminate early and leaking the
   first allocated interrupt.

 - Handle a corner case in GIC-V4 versus a lazily mapped Virtual
   Processing Element (VPE). If the VPE has not been mapped because the
   guest has not yet emitted a mapping command, then the set_affinity()
   callback returns an error code, which causes the vCPU management to
   fail.

   Return success in this case without touching the hardware. This will
   be done later when the guest issues the mapping command.

* tag 'irq-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v4: Correctly deal with set_affinity on lazily-mapped VPEs
  genirq/msi: Fix off-by-one error in msi_domain_alloc()

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ab597e74ba08..52f625e07658 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3810,8 +3810,18 @@ static int its_vpe_set_affinity(struct irq_data *d,
 	 * Check if we're racing against a VPE being destroyed, for
 	 * which we don't want to allow a VMOVP.
 	 */
-	if (!atomic_read(&vpe->vmapp_count))
-		return -EINVAL;
+	if (!atomic_read(&vpe->vmapp_count)) {
+		if (gic_requires_eager_mapping())
+			return -EINVAL;
+
+		/*
+		 * If we lazily map the VPEs, this isn't an error and
+		 * we can exit cleanly.
+		 */
+		cpu = cpumask_first(mask_val);
+		irq_data_update_effective_affinity(d, cpumask_of(cpu));
+		return IRQ_SET_MASK_OK_DONE;
+	}
 
 	/*
 	 * Changing affinity is mega expensive, so let's be as lazy as