From 12ec20c732a63f26dc243a847343b8b796c2d88c Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Wed, 18 Jan 2017 18:54:08 +0000 Subject: [PATCH] xen/arm: gic-v3: Make sure read from ICC_IAR1_EL1 is visible on the redistributor "The effects of reading ICC_IAR0_EL1 and ICC_IAR1_EL1 on the state of a returned INTID are not guaranteed to be visible until after the execution of a DSB". Because of the GIC is an external component, a dsb sy is required. Without it the sysreg read may not have been made visible on the redistributor. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- xen/arch/arm/gic-v3.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c index 57ed9d9e78..955591b744 100644 --- a/xen/arch/arm/gic-v3.c +++ b/xen/arch/arm/gic-v3.c @@ -459,7 +459,11 @@ static void gicv3_dir_irq(struct irq_desc *irqd) static unsigned int gicv3_read_irq(void) { - return READ_SYSREG32(ICC_IAR1_EL1); + unsigned int irq = READ_SYSREG32(ICC_IAR1_EL1); + + dsb(sy); + + return irq; } static inline uint64_t gicv3_mpidr_to_affinity(int cpu) -- 2.30.2