The GICv5 IRS keeps data structures in system memory.  (Notably, it
stores per-interrupt configuration information like the interrupt
priority and its active and pending state in an in-memory data
structure.) Add a link property so that the board or SoC can wire up
a MemoryRegion that we will do DMA to.  We name this property
"sysmem" to match the GICv3's equivalent property.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
---
 hw/intc/arm_gicv5_common.c         | 8 ++++++++
 include/hw/intc/arm_gicv5_common.h | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/hw/intc/arm_gicv5_common.c b/hw/intc/arm_gicv5_common.c
index b58913b970..29cc96917e 100644
--- a/hw/intc/arm_gicv5_common.c
+++ b/hw/intc/arm_gicv5_common.c
@@ -122,6 +122,12 @@ static void gicv5_common_realize(DeviceState *dev, Error **errp)
                    cs->spi_base, cs->spi_irs_range, cs->spi_range);
         return;
     }
+    if (!cs->dma) {
+        error_setg(errp, "sysmem link property not set");
+        return;
+    }
+
+    address_space_init(&cs->dma_as, cs->dma, "gicv5-sysmem");
 
     trace_gicv5_common_realize(cs->irsid, cs->num_cpus,
                                cs->spi_base, cs->spi_irs_range, cs->spi_range);
@@ -137,6 +143,8 @@ static const Property arm_gicv5_common_properties[] = {
     DEFINE_PROP_UINT32("spi-base", GICv5Common, spi_base, 0),
     DEFINE_PROP_UINT32("spi-irs-range", GICv5Common, spi_irs_range,
                        GICV5_SPI_IRS_RANGE_NOT_SET),
+    DEFINE_PROP_LINK("sysmem", GICv5Common, dma, TYPE_MEMORY_REGION,
+                     MemoryRegion *),
 };
 
 static void gicv5_common_class_init(ObjectClass *oc, const void *data)
diff --git a/include/hw/intc/arm_gicv5_common.h b/include/hw/intc/arm_gicv5_common.h
index 906870e49f..900af53b0f 100644
--- a/include/hw/intc/arm_gicv5_common.h
+++ b/include/hw/intc/arm_gicv5_common.h
@@ -83,6 +83,10 @@ struct GICv5Common {
     uint32_t num_cpu_iaffids;
     uint32_t *cpu_iaffids;
 
+    /* MemoryRegion and AS to DMA to/from for in-memory data structures */
+    MemoryRegion *dma;
+    AddressSpace dma_as;
+
     uint32_t irsid;
     uint32_t spi_base;
     uint32_t spi_irs_range;
-- 
2.43.0