[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v7 1/2] arm: remove irq from inflight, then change physical affinity
This patch fixes a potential race that could happen when gic_update_one_lr and vgic_vcpu_inject_irq run simultaneously. When GIC_IRQ_GUEST_MIGRATING is set, we must make sure that the irq has been removed from inflight before changing physical affinity, to avoid concurrent accesses to p->inflight, as vgic_vcpu_inject_irq will take a different vcpu lock. Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> Reviewed-by: Julien Grall <julien.grall@xxxxxxx> --- xen/arch/arm/gic.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index 9522c6c..2455d8f 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -503,6 +503,13 @@ static void gic_update_one_lr(struct vcpu *v, int i) gic_raise_guest_irq(v, irq, p->priority); else { list_del_init(&p->inflight); + /* + * Remove from inflight, then change physical affinity. It + * makes sure that when a new interrupt is received on the + * next pcpu, inflight is already cleared. No concurrent + * accesses to inflight. + */ + smp_wmb(); if ( test_and_clear_bit(GIC_IRQ_GUEST_MIGRATING, &p->status) ) { struct vcpu *v_target = vgic_get_target_vcpu(v, irq); -- 1.9.1 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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