From abb3009baf90e5984ff1c230af0bc92a45e64864 Mon Sep 17 00:00:00 2001
From: Jonathan Cameron <jonathan.cameron@huawei.com>
Date: Fri, 29 Apr 2022 15:40:38 +0100
Subject: [PATCH] cxl: Machine level control on whether CXL support is enabled
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There are going to be some potential overheads to CXL enablement,
for example the host bridge region reserved in memory maps.
Add a machine level control so that CXL is disabled by default.
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-14-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/core/machine.c | 28 ++++++++++++++++++++++++++++
hw/i386/pc.c | 1 +
include/hw/boards.h | 2 ++
include/hw/cxl/cxl.h | 4 ++++
4 files changed, 35 insertions(+)
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 3264c1e11d..b03d9192ba 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -33,6 +33,7 @@
#include "sysemu/qtest.h"
#include "hw/pci/pci.h"
#include "hw/mem/nvdimm.h"
+#include "hw/cxl/cxl.h"
#include "migration/global_state.h"
#include "migration/vmstate.h"
#include "exec/confidential-guest-support.h"
@@ -625,6 +626,20 @@ static void machine_set_nvdimm_persistence(Object *obj, const char *value,
nvdimms_state->persistence_string = g_strdup(value);
}
+static bool machine_get_cxl(Object *obj, Error **errp)
+{
+ MachineState *ms = MACHINE(obj);
+
+ return ms->cxl_devices_state->is_enabled;
+}
+
+static void machine_set_cxl(Object *obj, bool value, Error **errp)
+{
+ MachineState *ms = MACHINE(obj);
+
+ ms->cxl_devices_state->is_enabled = value;
+}
+
void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const char *type)
{
QAPI_LIST_PREPEND(mc->allowed_dynamic_sysbus_devices, g_strdup(type));
@@ -911,6 +926,8 @@ static void machine_class_init(ObjectClass *oc, void *data)
mc->default_ram_size = 128 * MiB;
mc->rom_file_has_mr = true;
+ /* Few machines support CXL, so default to off */
+ mc->cxl_supported = false;
/* numa node memory size aligned on 8MB by default.
* On Linux, each node's border has to be 8MB aligned
*/
@@ -1071,6 +1088,16 @@ static void machine_initfn(Object *obj)
"Valid values are cpu, mem-ctrl");
}
+ if (mc->cxl_supported) {
+ Object *obj = OBJECT(ms);
+
+ ms->cxl_devices_state = g_new0(CXLState, 1);
+ object_property_add_bool(obj, "cxl", machine_get_cxl, machine_set_cxl);
+ object_property_set_description(obj, "cxl",
+ "Set on/off to enable/disable "
+ "CXL instantiation");
+ }
+
if (mc->cpu_index_to_instance_props && mc->get_default_cpu_node_id) {
ms->numa_state = g_new0(NumaState, 1);
object_property_add_bool(obj, "hmat",
@@ -1108,6 +1135,7 @@ static void machine_finalize(Object *obj)
g_free(ms->device_memory);
g_free(ms->nvdimms_state);
g_free(ms->numa_state);
+ g_free(ms->cxl_devices_state);
}
bool machine_usb(MachineState *machine)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 305d2c0820..45e2d6092f 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1761,6 +1761,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;
mc->nvdimm_supported = true;
mc->smp_props.dies_supported = true;
+ mc->cxl_supported = true;
mc->default_ram_id = "pc.ram";
object_class_property_add(oc, PC_MACHINE_MAX_RAM_BELOW_4G, "size",
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 7b416c9787..fa57bac4fb 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -269,6 +269,7 @@ struct MachineClass {
bool ignore_boot_device_suffixes;
bool smbus_no_migration_support;
bool nvdimm_supported;
+ bool cxl_supported;
bool numa_mem_supported;
bool auto_enable_numa;
SMPCompatProps smp_props;
@@ -359,6 +360,7 @@ struct MachineState {
CPUArchIdList *possible_cpus;
CpuTopology smp;
struct NVDIMMState *nvdimms_state;
+ struct CXLState *cxl_devices_state;
struct NumaState *numa_state;
};
diff --git a/include/hw/cxl/cxl.h b/include/hw/cxl/cxl.h
index 554ad93b6b..31af92fd5e 100644
--- a/include/hw/cxl/cxl.h
+++ b/include/hw/cxl/cxl.h
@@ -17,4 +17,8 @@
#define CXL_COMPONENT_REG_BAR_IDX 0
#define CXL_DEVICE_REG_BAR_IDX 2
+typedef struct CXLState {
+ bool is_enabled;
+} CXLState;
+
#endif
--
2.30.2