[PATCH v4][PART 2 05/10] xen/arm: irq: avoid local IRQ descriptors reinit on system resume

[Mykola Kvach <xakep.amatop@xxxxxxxxx>]

From: Mykola Kvach <mykola_kvach@xxxxxxxx>

On ARM, during system resume, CPUs are brought online again. This normally
triggers init_local_irq_data, which reinitializes IRQ descriptors for
banked interrupts (SGIs and PPIs).

These descriptors are statically allocated per CPU and retain valid
state across suspend/resume cycles. Re-initializing them on resume is
unnecessary and may result in loss of interrupt configuration or
restored state.

This patch skips init_local_irq_data when system_state is set to
SYS_STATE_resume to preserve banked IRQ descs state during resume.

Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
---
 xen/arch/arm/irq.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
index 03fbb90c6c..372716a73b 100644
--- a/xen/arch/arm/irq.c
+++ b/xen/arch/arm/irq.c
@@ -122,6 +122,10 @@ static int cpu_callback(struct notifier_block *nfb, 
unsigned long action,
     switch ( action )
     {
     case CPU_UP_PREPARE:
+        /* Skip local IRQ cleanup on resume */
+        if ( system_state == SYS_STATE_resume )
+            break;
+
         rc = init_local_irq_data(cpu);
         if ( rc )
             printk(XENLOG_ERR "Unable to allocate local IRQ for CPU%u\n",
-- 
2.48.1