hw/cxl/component: Implement host bridge MMIO (8.2.5, table 142)

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.
Also hook up the device reset now that we have have the MMIO
space in which the results are visible.

Note that we duplicate the PCI express case for the aml_build but
the implementations will diverge when the CXL specific _OSC is
introduced.

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>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-24-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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"
@@ -1572,10 +1573,21 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
             }
 
             scope = aml_scope("\\_SB");
-            dev = aml_device("PC%.02X", bus_num);
+
+            if (pci_bus_is_cxl(bus)) {
+                dev = aml_device("CL%.02X", bus_num);
+            } else {
+                dev = aml_device("PC%.02X", bus_num);
+            }
             aml_append(dev, aml_name_decl("_UID", aml_int(bus_num)));
             aml_append(dev, aml_name_decl("_BBN", aml_int(bus_num)));
-            if (pci_bus_is_express(bus)) {
+            if (pci_bus_is_cxl(bus)) {
+                aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
+                aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
+
+                /* Expander bridges do not have ACPI PCI Hot-plug enabled */
+                aml_append(dev, build_q35_osc_method(true));
+            } else if (pci_bus_is_express(bus)) {
                 aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
                 aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
 
@@ -1595,6 +1607,15 @@ 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 (pci_bus_is_cxl(bus)) {
+                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);
+            }
         }
     }
 

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"
@@ -816,6 +817,7 @@ 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);
@@ -905,6 +907,26 @@ 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);
 
@@ -965,7 +987,10 @@ 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);

hw/pci-bridge/pci_expander_bridge.c

@@ -61,12 +61,6 @@ DECLARE_INSTANCE_CHECKER(PXBDev, PXB_PCIE_DEV,
 DECLARE_INSTANCE_CHECKER(PXBDev, PXB_CXL_DEV,
                          TYPE_PXB_CXL_DEVICE)
 
-typedef struct CXLHost {
-    PCIHostState parent_obj;
-
-    CXLComponentState cxl_cstate;
-} CXLHost;
-
 struct PXBDev {
     /*< private >*/
     PCIDevice parent_obj;
@@ -75,6 +69,9 @@ struct PXBDev {
     uint8_t bus_nr;
     uint16_t numa_node;
     bool bypass_iommu;
+    struct cxl_dev {
+        CXLHost *cxl_host_bridge;
+    } cxl;
 };
 
 static PXBDev *convert_to_pxb(PCIDevice *dev)
@@ -197,6 +194,52 @@ 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;
+
+    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.
  */
@@ -245,6 +288,13 @@ static int pxb_map_irq_fn(PCIDevice *pci_dev, int pin)
 
 static void pxb_dev_reset(DeviceState *dev)
 {
+    CXLHost *cxl = PXB_CXL_DEV(dev)->cxl.cxl_host_bridge;
+    CXLComponentState *cxl_cstate = &cxl->cxl_cstate;
+    uint32_t *reg_state = cxl_cstate->crb.cache_mem_registers;
+    uint32_t *write_msk = cxl_cstate->crb.cache_mem_regs_write_mask;
+
+    cxl_component_register_init_common(reg_state, write_msk, CXL2_ROOT_PORT);
+    ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, TARGET_COUNT, 8);
 }
 
 static gint pxb_compare(gconstpointer a, gconstpointer b)
@@ -281,12 +331,13 @@ 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) {
         bus = pci_root_bus_new(ds, dev_name, NULL, NULL, 0, TYPE_PXB_CXL_BUS);
         bus->flags |= PCI_BUS_CXL;
+        PXB_CXL_DEV(dev)->cxl.cxl_host_bridge = PXB_CXL_HOST(ds);
     } else {
         bus = pci_root_bus_new(ds, "pxb-internal", NULL, NULL, 0, TYPE_PXB_BUS);
         bds = qdev_new("pci-bridge");
@@ -475,6 +526,7 @@ 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);

include/hw/cxl/cxl.h

@@ -10,6 +10,7 @@
 #ifndef CXL_H
 #define CXL_H
 
+#include "hw/pci/pci_host.h"
 #include "cxl_pci.h"
 #include "cxl_component.h"
 #include "cxl_device.h"
@@ -17,8 +18,21 @@
 #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;
 
+struct CXLHost {
+    PCIHostState parent_obj;
+
+    CXLComponentState cxl_cstate;
+};
+
+#define TYPE_PXB_CXL_HOST "pxb-cxl-host"
+OBJECT_DECLARE_SIMPLE_TYPE(CXLHost, PXB_CXL_HOST)
+
 #endif