irqchip/gic-v3-its: Add a cache invalidation right after vPE unmapping

In order to be able to manipulate the VPT once a vPE has been
unmapped, perform the required CMO to invalidate the CPU view
of the VPT.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Shenming Lu <lushenming@huawei.com>
Link: https://lore.kernel.org/r/20210322060158.1584-2-lushenming@huawei.com

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ed46e6057e3350fbc31cb381270010b1d56ee746..4eb907f65bd05bba6e9737e52acad771cbe60a55 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -4554,6 +4554,15 @@ static void its_vpe_irq_domain_deactivate(struct irq_domain *domain,
 
                its_send_vmapp(its, vpe, false);
        }
+
+       /*
+        * There may be a direct read to the VPT after unmapping the
+        * vPE, to guarantee the validity of this, we make the VPT
+        * memory coherent with the CPU caches here.
+        */
+       if (find_4_1_its() && !atomic_read(&vpe->vmapp_count))
+               gic_flush_dcache_to_poc(page_address(vpe->vpt_page),
+                                       LPI_PENDBASE_SZ);
 }
 
 static const struct irq_domain_ops its_vpe_domain_ops = {