pci/pci_expander_bridge: For CXL HB delay the HB register memory region setup.

As the CXLState will no long be accessible via MachineState
at time of PXB_CXL realization, come back later from the machine specific
code to fill in the missing memory region setup. Only at this stage
is it possible to check if cxl=on, so that check is moved to this
later point.

Note that for multiple host bridges, the allocation order of the
register spaces is changed. This will be reflected in ACPI CEDT.

Stubs are added to handle case of CONFIG_PXB=n for machines that
call these functions.

The bus walking logic is common to all machines so add a utility
function + stub to cxl-host*.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Message-Id: <20220608145440.26106-6-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/cxl/cxl-host-stubs.c b/hw/cxl/cxl-host-stubs.c
index e0d5ec8ad5bc724a05078e3872b9a61668a2698e..cae4afcdde261fb970d212a8f74d2a64ecef8592 100644 (file)
--- a/hw/cxl/cxl-host-stubs.c
+++ b/hw/cxl/cxl-host-stubs.c
@@ -10,5 +10,6 @@
 
 void cxl_fmws_link_targets(CXLState *stat, Error **errp) {};
 void cxl_machine_init(Object *obj, CXLState *state) {};
+void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp) {};
 
 const MemoryRegionOps cfmws_ops;

diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
index 8e7738a65b8280fe6e4650e19418b32fd51efef1..efa14908d8cefc0d4af0b1f01adb0931cf009169 100644 (file)
--- a/hw/cxl/cxl-host.c
+++ b/hw/cxl/cxl-host.c
@@ -20,6 +20,7 @@
 #include "hw/pci/pci_bridge.h"
 #include "hw/pci/pci_host.h"
 #include "hw/pci/pcie_port.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 
 static void cxl_fixed_memory_window_config(CXLState *cxl_state,
                                            CXLFixedMemoryWindowOptions *object,
@@ -280,3 +281,22 @@ void cxl_machine_init(Object *obj, CXLState *state)
     object_property_set_description(obj, "cxl-fmw",
                                     "CXL Fixed Memory Windows (array)");
 }
+
+void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp)
+{
+    /* Walk the pci busses looking for pxb busses to hook up */
+    if (bus) {
+        QLIST_FOREACH(bus, &bus->child, sibling) {
+            if (!pci_bus_is_root(bus)) {
+                continue;
+            }
+            if (pci_bus_is_cxl(bus)) {
+                if (!state->is_enabled) {
+                    error_setg(errp, "CXL host bridges present, but cxl=off");
+                    return;
+                }
+                pxb_cxl_hook_up_registers(state, bus, errp);
+            }
+        }
+    }
+}

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 6cecd74d580de6039c64086ae6c3231c6037c9b0..9f48d02739a3595f5c1bd09a4e99b57ed06f8562 100644 (file)
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -37,6 +37,7 @@
 #include "hw/ide.h"
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_bus.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 #include "hw/nvram/fw_cfg.h"
 #include "hw/timer/hpet.h"
 #include "hw/firmware/smbios.h"
@@ -735,6 +736,8 @@ void pc_machine_done(Notifier *notifier, void *data)
     MachineState *ms = MACHINE(pcms);
 
     if (ms->cxl_devices_state) {
+        cxl_hook_up_pxb_registers(pcms->bus, ms->cxl_devices_state,
+                                  &error_fatal);
         cxl_fmws_link_targets(ms->cxl_devices_state, &error_fatal);
     }
 

diff --git a/hw/pci-bridge/meson.build b/hw/pci-bridge/meson.build
index b6d26a03d551541e1bdac78c0b396370dce036ab..fdbe2e07c508cb38a6822cda66139e2a4f120813 100644 (file)
--- a/hw/pci-bridge/meson.build
+++ b/hw/pci-bridge/meson.build
@@ -3,7 +3,8 @@ pci_ss.add(files('pci_bridge_dev.c'))
 pci_ss.add(when: 'CONFIG_I82801B11', if_true: files('i82801b11.c'))
 pci_ss.add(when: 'CONFIG_IOH3420', if_true: files('ioh3420.c'))
 pci_ss.add(when: 'CONFIG_PCIE_PORT', if_true: files('pcie_root_port.c', 'gen_pcie_root_port.c', 'pcie_pci_bridge.c'))
-pci_ss.add(when: 'CONFIG_PXB', if_true: files('pci_expander_bridge.c'))
+pci_ss.add(when: 'CONFIG_PXB', if_true: files('pci_expander_bridge.c'),
+                               if_false: files('pci_expander_bridge_stubs.c'))
 pci_ss.add(when: 'CONFIG_XIO3130', if_true: files('xio3130_upstream.c', 'xio3130_downstream.c'))
 pci_ss.add(when: 'CONFIG_CXL', if_true: files('cxl_root_port.c'))
 
@@ -13,3 +14,5 @@ pci_ss.add(when: 'CONFIG_DEC_PCI', if_true: files('dec.c'))
 pci_ss.add(when: 'CONFIG_SIMBA', if_true: files('simba.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_PCI', if_true: pci_ss)
+
+softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('pci_expander_bridge_stubs.c'))

diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
index 02032360f59cbfc239c92f3e0657f6a7a712031b..c9e817aa58662bad2db54b2bb60462fc90a5ddba 100644 (file)
--- a/hw/pci-bridge/pci_expander_bridge.c
+++ b/hw/pci-bridge/pci_expander_bridge.c
@@ -17,6 +17,7 @@
 #include "hw/pci/pci_host.h"
 #include "hw/qdev-properties.h"
 #include "hw/pci/pci_bridge.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 #include "hw/cxl/cxl.h"
 #include "qemu/range.h"
 #include "qemu/error-report.h"
@@ -186,25 +187,38 @@ static const TypeInfo pxb_host_info = {
 
 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);
+}
+
+/*
+ * Host bridge realization has no means of knowning state associated
+ * with a particular machine. As such, it is nececssary to delay
+ * final setup of the host bridge register space until later in the
+ * machine bring up.
+ */
+void pxb_cxl_hook_up_registers(CXLState *cxl_state, PCIBus *bus, Error **errp)
+{
+    PXBDev *pxb =  PXB_CXL_DEV(pci_bridge_get_device(bus));
+    CXLHost *cxl = pxb->cxl.cxl_host_bridge;
+    CXLComponentState *cxl_cstate = &cxl->cxl_cstate;
+    struct MemoryRegion *mr = &cxl_cstate->crb.component_registers;
+    hwaddr offset;
 
-    offset = memory_region_size(mr) * ms->cxl_devices_state->next_mr_idx;
-    if (offset > memory_region_size(&ms->cxl_devices_state->host_mr)) {
+    offset = memory_region_size(mr) * cxl_state->next_mr_idx;
+    if (offset > memory_region_size(&cxl_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++;
+    memory_region_add_subregion(&cxl_state->host_mr, offset, mr);
+    cxl_state->next_mr_idx++;
 }
 
 static void pxb_cxl_host_class_init(ObjectClass *class, void *data)
@@ -461,17 +475,11 @@ static const TypeInfo pxb_pcie_dev_info = {
 
 static void pxb_cxl_dev_realize(PCIDevice *dev, Error **errp)
 {
-    MachineState *ms = MACHINE(qdev_get_machine());
-
     /* A CXL PXB's parent bus is still PCIe */
     if (!pci_bus_is_express(pci_get_bus(dev))) {
         error_setg(errp, "pxb-cxl devices cannot reside on a PCI bus");
         return;
     }
-    if (!ms->cxl_devices_state || !ms->cxl_devices_state->is_enabled) {
-        error_setg(errp, "Machine does not have cxl=on");
-        return;
-    }
 
     pxb_dev_realize_common(dev, CXL, errp);
     pxb_dev_reset(DEVICE(dev));

diff --git a/hw/pci-bridge/pci_expander_bridge_stubs.c b/hw/pci-bridge/pci_expander_bridge_stubs.c
new file mode 100644 (file)
index 0000000..b351803
--- /dev/null
+++ b/hw/pci-bridge/pci_expander_bridge_stubs.c
@@ -0,0 +1,14 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Stubs for calls made from machines to handle the case where CONFIG_PXB
+ * is not enabled.
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
+#include "hw/cxl/cxl.h"
+
+void pxb_cxl_hook_up_registers(CXLState *state, PCIBus *bus, Error **errp) {};

diff --git a/include/hw/cxl/cxl_host.h b/include/hw/cxl/cxl_host.h
index 4d642a81fa54f876c57260f88bd1731ebfd3016f..a1b662ce4063060eea3e2a4a345f2a65db72e66b 100644 (file)
--- a/include/hw/cxl/cxl_host.h
+++ b/include/hw/cxl/cxl_host.h
@@ -16,6 +16,7 @@
 
 void cxl_machine_init(Object *obj, CXLState *state);
 void cxl_fmws_link_targets(CXLState *stat, Error **errp);
+void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp);
 
 extern const MemoryRegionOps cfmws_ops;
 

diff --git a/include/hw/pci-bridge/pci_expander_bridge.h b/include/hw/pci-bridge/pci_expander_bridge.h
new file mode 100644 (file)
index 0000000..0b3856d
--- /dev/null
+++ b/include/hw/pci-bridge/pci_expander_bridge.h
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef PCI_EXPANDER_BRIDGE_H
+#define PCI_EXPANDER_BRIDGE_H
+
+#include "hw/cxl/cxl.h"
+
+void pxb_cxl_hook_up_registers(CXLState *state, PCIBus *bus, Error **errp);
+
+#endif /* PCI_EXPANDER_BRIDGE_H */