After the improvement to high memory region address assignment is
applied, the memory layout can be changed, introducing possible
migration breakage. For example, VIRT_HIGH_PCIE_MMIO memory region
is disabled or enabled when the optimization is applied or not, with
the following configuration.
pa_bits = 40;
vms->highmem_redists = false;
vms->highmem_ecam = false;
vms->highmem_mmio = true;
# qemu-system-aarch64 -accel kvm -cpu host \
-machine virt-7.2,compact-highmem={on, off} \
-m 4G,maxmem=511G -monitor stdio
Region compact-highmem=off compact-highmem=on
----------------------------------------------------------------
RAM [1GB 512GB] [1GB 512GB]
HIGH_GIC_REDISTS [512GB 512GB+64MB] [disabled]
HIGH_PCIE_ECAM [512GB+256MB 512GB+512MB] [disabled]
HIGH_PCIE_MMIO [disabled] [512GB 1TB]
In order to keep backwords compatibility, we need to disable the
optimization on machines, which is virt-7.1 or ealier than it. It
means the optimization is enabled by default from virt-7.2. Besides,
'compact-highmem' property is added so that the optimization can be
explicitly enabled or disabled on all machine types by users.
Signed-off-by: Gavin Shan <gs...@redhat.com>
---
docs/system/arm/virt.rst | 4 ++++
hw/arm/virt.c | 47 ++++++++++++++++++++++++++++++++++++++++
include/hw/arm/virt.h | 1 +
3 files changed, 52 insertions(+)
diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
index 20442ea2c1..75bf5a4994 100644
--- a/docs/system/arm/virt.rst
+++ b/docs/system/arm/virt.rst
@@ -94,6 +94,10 @@ highmem
address space above 32 bits. The default is ``on`` for machine types
later than ``virt-2.12``.
+compact-highmem
+ Set ``on``/``off`` to enable/disable compact space for high memory regions.
+ The default is ``on`` for machine types later than ``virt-7.2``
+
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 4164da49e9..9fe65a2ae1 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -174,6 +174,27 @@ static const MemMapEntry base_memmap[] = {
* Note the extended_memmap is sized so that it eventually also includes the
* base_memmap entries (VIRT_HIGH_GIC_REDIST2 index is greater than the last
* index of base_memmap).
+ *
+ * The addresses assigned to these regions are affected by 'compact-highmem'
+ * property, which is to enable or disable the compact space in the Highmem
+ * IO regions. For example, VIRT_HIGH_PCIE_MMIO can be disabled or enabled
+ * depending on the property in the following scenario.
+ *
+ * pa_bits = 40;
+ * vms->highmem_redists = false;
+ * vms->highmem_ecam = false;
+ * vms->highmem_mmio = true;
+ *
+ * # qemu-system-aarch64 -accel kvm -cpu host \
+ * -machine virt-7.2,compact-highmem={on, off} \
+ * -m 4G,maxmem=511G -monitor stdio
+ *
+ * Region compact-highmem=off compact-highmem=on
+ * ----------------------------------------------------------------
+ * RAM [1GB 512GB] [1GB 512GB]
+ * HIGH_GIC_REDISTS [512GB 512GB+64MB] [disabled]
+ * HIGH_PCIE_ECAM [512GB+256GB 512GB+512MB] [disabled]
+ * HIGH_PCIE_MMIO [disabled] [512GB 1TB]
*/
static MemMapEntry extended_memmap[] = {
/* Additional 64 MB redist region (can contain up to 512 redistributors) */
@@ -2349,6 +2370,20 @@ static void virt_set_highmem(Object *obj, bool value,
Error **errp)
vms->highmem = value;
}
+static bool virt_get_compact_highmem(Object *obj, Error **errp)
+{
+ VirtMachineState *vms = VIRT_MACHINE(obj);
+
+ return vms->highmem_compact;
+}
+
+static void virt_set_compact_highmem(Object *obj, bool value, Error **errp)
+{
+ VirtMachineState *vms = VIRT_MACHINE(obj);
+
+ vms->highmem_compact = value;
+}
+
static bool virt_get_its(Object *obj, Error **errp)
{
VirtMachineState *vms = VIRT_MACHINE(obj);
@@ -2967,6 +3002,13 @@ static void virt_machine_class_init(ObjectClass *oc,
void *data)
"Set on/off to enable/disable using "
"physical address space above 32
bits");
+ object_class_property_add_bool(oc, "compact-highmem",
+ virt_get_compact_highmem,
+ virt_set_compact_highmem);
+ object_class_property_set_description(oc, "compact-highmem",
+ "Set on/off to enable/disable
compact "
+ "space for high memory regions");
+
object_class_property_add_str(oc, "gic-version", virt_get_gic_version,
virt_set_gic_version);
object_class_property_set_description(oc, "gic-version",
@@ -3051,6 +3093,7 @@ static void virt_instance_init(Object *obj)
/* High memory is enabled by default */
vms->highmem = true;
+ vms->highmem_compact = !vmc->no_highmem_compact;
vms->gic_version = VIRT_GIC_VERSION_NOSEL;
vms->highmem_ecam = !vmc->no_highmem_ecam;
@@ -3120,8 +3163,12 @@ DEFINE_VIRT_MACHINE_AS_LATEST(7, 2)
static void virt_machine_7_1_options(MachineClass *mc)
{
+ VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
+
virt_machine_7_2_options(mc);
compat_props_add(mc->compat_props, hw_compat_7_1, hw_compat_7_1_len);
+ /* Compact space for high memory regions was introduced with 7.2 */
+ vmc->no_highmem_compact = true;
}
DEFINE_VIRT_MACHINE(7, 1)
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index 709f623741..c7dd59d7f1 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -125,6 +125,7 @@ struct VirtMachineClass {
bool no_pmu;
bool claim_edge_triggered_timers;
bool smbios_old_sys_ver;
+ bool no_highmem_compact;
bool no_highmem_ecam;
bool no_ged; /* Machines < 4.2 have no support for ACPI GED device */
bool kvm_no_adjvtime;
--
2.23.0
