X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.
This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.
Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/irq.h | 2 ++
kernel/irq/chip.c | 5 ++++-
2 files changed, 6 insertions(+), 1 deletion(-)
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -569,6 +569,7 @@ struct irq_chip {
* IRQCHIP_SUPPORTS_NMI: Chip can deliver NMIs, only for root irqchips
* IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND: Invokes __enable_irq()/__disable_irq() for wake irqs
* in the suspend path if they are in disabled state
+ * IRQCHIP_AFFINITY_PRE_STARTUP: Default affinity update before startup
*/
enum {
IRQCHIP_SET_TYPE_MASKED = (1 << 0),
@@ -581,6 +582,7 @@ enum {
IRQCHIP_SUPPORTS_LEVEL_MSI = (1 << 7),
IRQCHIP_SUPPORTS_NMI = (1 << 8),
IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND = (1 << 9),
+ IRQCHIP_AFFINITY_PRE_STARTUP = (1 << 10),
};
#include <linux/irqdesc.h>
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -265,8 +265,11 @@ int irq_startup(struct irq_desc *desc, b
} else {
switch (__irq_startup_managed(desc, aff, force)) {
case IRQ_STARTUP_NORMAL:
+ if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)
+ irq_setup_affinity(desc);
ret = __irq_startup(desc);
- irq_setup_affinity(desc);
+ if (!(d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP))
+ irq_setup_affinity(desc);
break;
case IRQ_STARTUP_MANAGED:
irq_do_set_affinity(d, aff, false);
