[PATCH v4 18/42] hw/cxl/component: Implement host bridge MMIO (8.2.5, table 142)

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

From: Ben Widawsky <ben.widawsky@intel.com>

CXL host bridges themselves may have MMIO. Since host bridges don't have
a BAR they are treated as special for MMIO.  This patch includes
i386/pc support.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 hw/i386/acpi-build.c                | 26 +++++++++++---
 hw/i386/pc.c                        | 27 ++++++++++++++-
 hw/pci-bridge/pci_expander_bridge.c | 53 ++++++++++++++++++++++++++++-
 include/hw/cxl/cxl.h                |  4 +++
 4 files changed, 104 insertions(+), 6 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 1d8ee988f2..ad4f8eb22a 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -28,6 +28,7 @@
 #include "qemu/bitmap.h"
 #include "qemu/error-report.h"
 #include "hw/pci/pci.h"
+#include "hw/cxl/cxl.h"
 #include "hw/core/cpu.h"
 #include "target/i386/cpu.h"
 #include "hw/misc/pvpanic.h"
@@ -1398,7 +1399,7 @@ static void build_smb0(Aml *table, I2CBus *smbus, int devnr, int func)
     aml_append(table, scope);
 }
 
-enum { PCI, PCIE };
+enum { PCI, PCIE, CXL };
 static void init_pci_acpi(Aml *dev, int uid, int type, bool native_pcie_hp)
 {
     if (type == PCI) {
@@ -1561,22 +1562,30 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         QLIST_FOREACH(bus, &bus->child, sibling) {
             uint8_t bus_num = pci_bus_num(bus);
             uint8_t numa_node = pci_bus_numa_node(bus);
+            int32_t uid = bus_num; /* TODO: Explicit uid */
+            int type;
 
             /* look only for expander root buses */
             if (!pci_bus_is_root(bus)) {
                 continue;
             }
 
+            type = pci_bus_is_cxl(bus) ? CXL :
+                                         pci_bus_is_express(bus) ? PCIE : PCI;
+
             if (bus_num < root_bus_limit) {
                 root_bus_limit = bus_num - 1;
             }
 
             scope = aml_scope("\\_SB");
-            dev = aml_device("PC%.02X", bus_num);
+            if (type == CXL) {
+                dev = aml_device("CL%.02X", uid);
+            } else {
+                dev = aml_device("PC%.02X", bus_num);
+            }
             aml_append(dev, aml_name_decl("_BBN", aml_int(bus_num)));
 
-            init_pci_acpi(dev, bus_num,
-                          pci_bus_is_express(bus) ? PCIE : PCI, true);
+            init_pci_acpi(dev, uid, type, true);
 
             if (numa_node != NUMA_NODE_UNASSIGNED) {
                 aml_append(dev, aml_name_decl("_PXM", aml_int(numa_node)));
@@ -1588,6 +1597,15 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
             aml_append(dev, aml_name_decl("_CRS", crs));
             aml_append(scope, dev);
             aml_append(dsdt, scope);
+
+            /* Handle the ranges for the PXB expanders */
+            if (type == CXL) {
+                MemoryRegion *mr = &machine->cxl_devices_state->host_mr;
+                uint64_t base = mr->addr;
+
+                crs_range_insert(crs_range_set.mem_ranges, base,
+                                 base + memory_region_size(mr) - 1);
+            }
         }
     }
 
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index b6800a511a..7a18dce529 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -75,6 +75,7 @@
 #include "acpi-build.h"
 #include "hw/mem/pc-dimm.h"
 #include "hw/mem/nvdimm.h"
+#include "hw/cxl/cxl.h"
 #include "qapi/error.h"
 #include "qapi/qapi-visit-common.h"
 #include "qapi/qapi-visit-machine.h"
@@ -815,6 +816,7 @@ void pc_memory_init(PCMachineState *pcms,
     MachineClass *mc = MACHINE_GET_CLASS(machine);
     PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
     X86MachineState *x86ms = X86_MACHINE(pcms);
+    hwaddr cxl_base;
 
     assert(machine->ram_size == x86ms->below_4g_mem_size +
                                 x86ms->above_4g_mem_size);
@@ -904,6 +906,26 @@ void pc_memory_init(PCMachineState *pcms,
                                     &machine->device_memory->mr);
     }
 
+    if (machine->cxl_devices_state->is_enabled) {
+        MemoryRegion *mr = &machine->cxl_devices_state->host_mr;
+        hwaddr cxl_size = MiB;
+
+        if (pcmc->has_reserved_memory && machine->device_memory->base) {
+            cxl_base = machine->device_memory->base;
+            if (!pcmc->broken_reserved_end) {
+                cxl_base += memory_region_size(&machine->device_memory->mr);
+            }
+        } else if (pcms->sgx_epc.size != 0) {
+            cxl_base = sgx_epc_above_4g_end(&pcms->sgx_epc);
+        } else {
+            cxl_base = 0x100000000ULL + x86ms->above_4g_mem_size;
+        }
+
+        e820_add_entry(cxl_base, cxl_size, E820_RESERVED);
+        memory_region_init(mr, OBJECT(machine), "cxl_host_reg", cxl_size);
+        memory_region_add_subregion(system_memory, cxl_base, mr);
+    }
+
     /* Initialize PC system firmware */
     pc_system_firmware_init(pcms, rom_memory);
 
@@ -964,7 +986,10 @@ uint64_t pc_pci_hole64_start(void)
     X86MachineState *x86ms = X86_MACHINE(pcms);
     uint64_t hole64_start = 0;
 
-    if (pcmc->has_reserved_memory && ms->device_memory->base) {
+    if (ms->cxl_devices_state->host_mr.addr) {
+        hole64_start = ms->cxl_devices_state->host_mr.addr +
+            memory_region_size(&ms->cxl_devices_state->host_mr);
+    } else if (pcmc->has_reserved_memory && ms->device_memory->base) {
         hole64_start = ms->device_memory->base;
         if (!pcmc->broken_reserved_end) {
             hole64_start += memory_region_size(&ms->device_memory->mr);
diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
index 7009b541de..e62d623551 100644
--- a/hw/pci-bridge/pci_expander_bridge.c
+++ b/hw/pci-bridge/pci_expander_bridge.c
@@ -200,6 +200,56 @@ static const TypeInfo pxb_host_info = {
     .class_init    = pxb_host_class_init,
 };
 
+static void pxb_cxl_realize(DeviceState *dev, Error **errp)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    CXLHost *cxl = PXB_CXL_HOST(dev);
+    CXLComponentState *cxl_cstate = &cxl->cxl_cstate;
+    struct MemoryRegion *mr = &cxl_cstate->crb.component_registers;
+    hwaddr offset;
+
+    if (!ms->cxl_devices_state->is_enabled) {
+        error_setg(errp, "Machine does not have cxl=on");
+        return;
+    }
+    cxl_component_register_block_init(OBJECT(dev), cxl_cstate,
+                                      TYPE_PXB_CXL_HOST);
+    sysbus_init_mmio(sbd, mr);
+
+    offset = memory_region_size(mr) * ms->cxl_devices_state->next_mr_idx;
+    if (offset > memory_region_size(&ms->cxl_devices_state->host_mr)) {
+        error_setg(errp, "Insufficient space for pxb cxl host register space");
+        return;
+    }
+
+    memory_region_add_subregion(&ms->cxl_devices_state->host_mr, offset, mr);
+    ms->cxl_devices_state->next_mr_idx++;
+}
+
+static void pxb_cxl_host_class_init(ObjectClass *class, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(class);
+    PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(class);
+
+    hc->root_bus_path = pxb_host_root_bus_path;
+    dc->fw_name = "cxl";
+    dc->realize = pxb_cxl_realize;
+    /* Reason: Internal part of the pxb/pxb-pcie device, not usable by itself */
+    dc->user_creatable = false;
+}
+
+/*
+ * This is a device to handle the MMIO for a CXL host bridge. It does nothing
+ * else.
+ */
+static const TypeInfo cxl_host_info = {
+    .name          = TYPE_PXB_CXL_HOST,
+    .parent        = TYPE_PCI_HOST_BRIDGE,
+    .instance_size = sizeof(CXLHost),
+    .class_init    = pxb_cxl_host_class_init,
+};
+
 /*
  * Registers the PXB bus as a child of pci host root bus.
  */
@@ -290,7 +340,7 @@ static void pxb_dev_realize_common(PCIDevice *dev, enum BusType type,
         dev_name = dev->qdev.id;
     }
 
-    ds = qdev_new(TYPE_PXB_HOST);
+    ds = qdev_new(type == CXL ? TYPE_PXB_CXL_HOST : TYPE_PXB_HOST);
     if (type == PCIE) {
         bus = pci_root_bus_new(ds, dev_name, NULL, NULL, 0, TYPE_PXB_PCIE_BUS);
     } else if (type == CXL) {
@@ -487,6 +537,7 @@ static void pxb_register_types(void)
     type_register_static(&pxb_pcie_bus_info);
     type_register_static(&pxb_cxl_bus_info);
     type_register_static(&pxb_host_info);
+    type_register_static(&cxl_host_info);
     type_register_static(&pxb_dev_info);
     type_register_static(&pxb_pcie_dev_info);
     type_register_static(&pxb_cxl_dev_info);
diff --git a/include/hw/cxl/cxl.h b/include/hw/cxl/cxl.h
index 31af92fd5e..75e5bf71e1 100644
--- a/include/hw/cxl/cxl.h
+++ b/include/hw/cxl/cxl.h
@@ -17,8 +17,12 @@
 #define CXL_COMPONENT_REG_BAR_IDX 0
 #define CXL_DEVICE_REG_BAR_IDX 2
 
+#define CXL_WINDOW_MAX 10
+
 typedef struct CXLState {
     bool is_enabled;
+    MemoryRegion host_mr;
+    unsigned int next_mr_idx;
 } CXLState;
 
 #endif
-- 
2.32.0