[tip: irq/core] x86/ioapic: Force affinity setup before startup

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     0c0e37dc11671384e53ba6ede53a4d91162a2cc5
Gitweb:        https://git.kernel.org/tip/0c0e37dc11671384e53ba6ede53a4d91162a2cc5
Author:        Thomas Gleixner [off-list ref]
AuthorDate:    Thu, 29 Jul 2021 23:51:49 +02:00
Committer:     Thomas Gleixner [off-list ref]
CommitterDate: Tue, 10 Aug 2021 10:59:21 +02:00

x86/ioapic: Force affinity setup before startup

The IO/APIC cannot handle interrupt affinity changes safely after startup
other than from an interrupt handler. The startup sequence in the generic
interrupt code violates that assumption.

Mark the irq chip with the new IRQCHIP_AFFINITY_PRE_STARTUP flag so that
the default interrupt setting happens before the interrupt is started up
for the first time.

Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <redacted>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.832143400@linutronix.de (local)


---
 arch/x86/kernel/apic/io_apic.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index d5c691a..39224e0 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c

@@ -1986,7 +1986,8 @@ static struct irq_chip ioapic_chip __read_mostly = {
 	.irq_set_affinity	= ioapic_set_affinity,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.irq_get_irqchip_state	= ioapic_irq_get_chip_state,
-	.flags			= IRQCHIP_SKIP_SET_WAKE,
+	.flags			= IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
 static struct irq_chip ioapic_ir_chip __read_mostly = {

@@ -1999,7 +2000,8 @@ static struct irq_chip ioapic_ir_chip __read_mostly = {
 	.irq_set_affinity	= ioapic_set_affinity,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.irq_get_irqchip_state	= ioapic_irq_get_chip_state,
-	.flags			= IRQCHIP_SKIP_SET_WAKE,
+	.flags			= IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
 static inline void init_IO_APIC_traps(void)