[PATCH v6 7/7] hw/arm/virt: Add properties to disable high memory regions

[Gavin Shan]

These 3 high memory regions are usually enabled by default, but
they may be not used. For example, VIRT_HIGH_GIC_REDIST2 isn't
needed by GICv2. This leads to waste in the PA space.

Add properties to allow users selectively disable them if needed:
"highmem-redists", "highmem-ecam", "highmem-mmio".

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 docs/system/arm/virt.rst | 12 ++++++++
 hw/arm/virt.c            | 64 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
index 4454706392..a1668a969d 100644
--- a/docs/system/arm/virt.rst
+++ b/docs/system/arm/virt.rst
@@ -98,6 +98,18 @@ compact-highmem
   Set ``on``/``off`` to enable/disable the compact layout for high memory 
regions.
   The default is ``on`` for machine types later than ``virt-7.2``.
 
+highmem-redists
+  Set ``on``/``off`` to enable/disable the high memry region for GICv3/4
+  redistributor. The default is ``on``.
+
+highmem-ecam
+  Set ``on``/``off`` to enable/disable the high memry region for PCI ECAM.
+  The default is ``on`` for machine types later than ``virt-3.0``.
+
+highmem-mmio
+  Set ``on``/``off`` to enable/disable the high memry region for PCI MMIO.
+  The default is ``on``.
+
 gic-version
   Specify the version of the Generic Interrupt Controller (GIC) to provide.
   Valid values are:
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 11b5685432..afafc2d1b8 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2371,6 +2371,49 @@ static void virt_set_compact_highmem(Object *obj, bool 
value, Error **errp)
     vms->highmem_compact = value;
 }
 
+static bool virt_get_highmem_redists(Object *obj, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(obj);
+
+    return vms->highmem_redists;
+}
+
+static void virt_set_highmem_redists(Object *obj, bool value, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(obj);
+
+    vms->highmem_redists = value;
+}
+
+static bool virt_get_highmem_ecam(Object *obj, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(obj);
+
+    return vms->highmem_ecam;
+}
+
+static void virt_set_highmem_ecam(Object *obj, bool value, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(obj);
+
+    vms->highmem_ecam = value;
+}
+
+static bool virt_get_highmem_mmio(Object *obj, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(obj);
+
+    return vms->highmem_mmio;
+}
+
+static void virt_set_highmem_mmio(Object *obj, bool value, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(obj);
+
+    vms->highmem_mmio = value;
+}
+
+
 static bool virt_get_its(Object *obj, Error **errp)
 {
     VirtMachineState *vms = VIRT_MACHINE(obj);
@@ -2996,6 +3039,27 @@ static void virt_machine_class_init(ObjectClass *oc, 
void *data)
                                           "Set on/off to enable/disable 
compact "
                                           "layout for high memory regions");
 
+    object_class_property_add_bool(oc, "highmem-redists",
+                                   virt_get_highmem_redists,
+                                   virt_set_highmem_redists);
+    object_class_property_set_description(oc, "highmem-redists",
+                                          "Set on/off to enable/disable high "
+                                          "memory region for GICv3/4 
redistributor");
+
+    object_class_property_add_bool(oc, "highmem-ecam",
+                                   virt_get_highmem_ecam,
+                                   virt_set_highmem_ecam);
+    object_class_property_set_description(oc, "highmem-ecam",
+                                          "Set on/off to enable/disable high "
+                                          "memory region for PCI ECAM");
+
+    object_class_property_add_bool(oc, "highmem-mmio",
+                                   virt_get_highmem_mmio,
+                                   virt_set_highmem_mmio);
+    object_class_property_set_description(oc, "highmem-mmio",
+                                          "Set on/off to enable/disable high "
+                                          "memory region for PCI MMIO");
+
     object_class_property_add_str(oc, "gic-version", virt_get_gic_version,
                                   virt_set_gic_version);
     object_class_property_set_description(oc, "gic-version",
-- 
2.23.0