powerpc/64: Replay hypervisor maintenance interrupt first

The HMI (Hypervisor Maintenance Interrupt) is defined by the
architecture to be higher priority than other maskable interrupts, so
replay it first, as a best-effort to replay according to hardware
priorities.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 9594ac8..471f65a 100644 (file)
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -157,6 +157,15 @@ notrace unsigned int __check_irq_replay(void)
        }
 
        /*
+        * Check if an hypervisor Maintenance interrupt happened.
+        * This is a higher priority interrupt than the others, so
+        * replay it first.
+        */
+       local_paca->irq_happened &= ~PACA_IRQ_HMI;
+       if (happened & PACA_IRQ_HMI)
+               return 0xe60;
+
+       /*
         * We may have missed a decrementer interrupt. We check the
         * decrementer itself rather than the paca irq_happened field
         * in case we also had a rollover while hard disabled
@@ -191,11 +200,6 @@ notrace unsigned int __check_irq_replay(void)
        }
 #endif /* CONFIG_PPC_BOOK3E */
 
-       /* Check if an hypervisor Maintenance interrupt happened */
-       local_paca->irq_happened &= ~PACA_IRQ_HMI;
-       if (happened & PACA_IRQ_HMI)
-               return 0xe60;
-
        /* There should be nothing left ! */
        BUG_ON(local_paca->irq_happened != 0);