[RFC PATCH 24/25] WIP: i386/cxl: Initialize a host bridge

[Ben Widawsky]

This patch allows initializing the primary host bridge as a CXL capable
hostbridge.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>

--
This patch is WIP.
---
 hw/arm/virt.c        |  1 +
 hw/core/machine.c    | 26 ++++++++++++++++++++++++++
 hw/i386/acpi-build.c |  8 +++++++-
 hw/i386/microvm.c    |  1 +
 hw/i386/pc.c         |  1 +
 hw/ppc/spapr.c       |  2 ++
 include/hw/boards.h  |  2 ++
 include/hw/cxl/cxl.h |  4 ++++
 8 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 27dbeb549e..9d1dafea9f 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2475,6 +2475,7 @@ static void virt_machine_class_init(ObjectClass *oc, void 
*data)
     hc->unplug_request = virt_machine_device_unplug_request_cb;
     hc->unplug = virt_machine_device_unplug_cb;
     mc->nvdimm_supported = true;
+    mc->cxl_supported = false;
     mc->auto_enable_numa_with_memhp = true;
     mc->auto_enable_numa_with_memdev = true;
     mc->default_ram_id = "mach-virt.ram";
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 98b87f76cb..5f37d63da6 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -26,6 +26,7 @@
 #include "sysemu/qtest.h"
 #include "hw/pci/pci.h"
 #include "hw/mem/nvdimm.h"
+#include "hw/cxl/cxl.h"
 #include "migration/vmstate.h"
 
 GlobalProperty hw_compat_5_1[] = {
@@ -491,6 +492,20 @@ 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)
 {
     strList *item = g_new0(strList, 1);
@@ -895,6 +910,16 @@ 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",
@@ -931,6 +956,7 @@ 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/acpi-build.c b/hw/i386/acpi-build.c
index d080e24228..465bde0196 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -53,6 +53,7 @@
 #include "sysemu/numa.h"
 #include "sysemu/reset.h"
 #include "hw/hyperv/vmbus-bridge.h"
+#include "hw/cxl/cxl.h"
 
 /* Supported chipsets: */
 #include "hw/southbridge/piix.h"
@@ -1569,8 +1570,13 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         build_piix4_pci0_int(dsdt);
     } else {
         sb_scope = aml_scope("_SB");
+        /*
+         * XXX: CXL spec calls this "CXL0", but that would require lots of
+         * changes throughout and so even for CXL enabled, we call it "PCI0"
+         */
         dev = aml_device("PCI0");
-        init_pci_acpi(dev, 0, PCIE);
+        init_pci_acpi(dev, 0,
+                machine->cxl_devices_state->is_enabled ? CXL : PCIE);
         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
         aml_append(sb_scope, dev);
 
diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index 5428448b70..ed2f992b2a 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -656,6 +656,7 @@ static void microvm_class_init(ObjectClass *oc, void *data)
     mc->auto_enable_numa_with_memdev = false;
     mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;
     mc->nvdimm_supported = false;
+    mc->cxl_supported = false;
     mc->default_ram_id = "microvm.ram";
 
     /* Avoid relying too much on kernel components */
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index ecfc497f71..a962a77835 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1694,6 +1694,7 @@ static void pc_machine_class_init(ObjectClass *oc, void 
*data)
     hc->unplug = pc_machine_device_unplug_cb;
     mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;
     mc->nvdimm_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/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 227075103e..3d72bad5f2 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4422,6 +4422,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
void *data)
     mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power9_v2.0");
     mc->has_hotpluggable_cpus = true;
     mc->nvdimm_supported = true;
+    mc->cxl_supported = false;
     smc->resize_hpt_default = SPAPR_RESIZE_HPT_ENABLED;
     fwc->get_dev_path = spapr_get_fw_dev_path;
     nc->nmi_monitor_handler = spapr_nmi;
@@ -4571,6 +4572,7 @@ static void spapr_machine_4_2_class_options(MachineClass 
*mc)
     smc->default_caps.caps[SPAPR_CAP_FWNMI] = SPAPR_CAP_OFF;
     smc->rma_limit = 16 * GiB;
     mc->nvdimm_supported = false;
+    mc->cxl_supported = false;
 }
 
 DEFINE_SPAPR_MACHINE(4_2, "4.2", false);
diff --git a/include/hw/boards.h b/include/hw/boards.h
index a49e3a6b44..f20ccc15c6 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -205,6 +205,7 @@ 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;
     const char *default_ram_id;
@@ -290,6 +291,7 @@ 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 809ed7de60..6961e47076 100644
--- a/include/hw/cxl/cxl.h
+++ b/include/hw/cxl/cxl.h
@@ -22,5 +22,9 @@
 #define CXL_HOST_BASE 0xD0000000
 #define CXL_WINDOW_MAX 10
 
+typedef struct CXLState {
+    bool is_enabled;
+} CXLState;
+
 #endif
 
-- 
2.29.2