From 4f8db8711cbd27c9acf17e685987e9e74815e087 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Fri, 29 Apr 2022 15:40:39 +0100 Subject: [PATCH] hw/pxb: Allow creation of a CXL PXB (host bridge) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This works like adding a typical pxb device, except the name is 'pxb-cxl' instead of 'pxb-pcie'. An example command line would be as follows: -device pxb-cxl,id=cxl.0,bus="pcie.0",bus_nr=1 A CXL PXB is backward compatible with PCIe. What this means in practice is that an operating system that is unaware of CXL should still be able to enumerate this topology as if it were PCIe. One can create multiple CXL PXB host bridges, but a host bridge can only be connected to the main root bus. Host bridges cannot appear elsewhere in the topology. Note that as of this patch, the ACPI tables needed for the host bridge (specifically, an ACPI object in _SB named ACPI0016 and the CEDT) aren't created. So while this patch internally creates it, it cannot be properly used by an operating system or other system software. Also necessary is to add an exception to scripts/device-crash-test similar to that for exiting pxb as both must created on a PCIexpress host bus. Signed-off-by: Ben Widawsky Signed-off-by: Jonathan.Cameron Reviewed-by: Alex Bennée Message-Id: <20220429144110.25167-15-Jonathan.Cameron@huawei.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/pci-bridge/pci_expander_bridge.c | 86 ++++++++++++++++++++++++++++- hw/pci/pci.c | 7 +++ include/hw/pci/pci.h | 6 ++ scripts/device-crash-test | 1 + 4 files changed, 98 insertions(+), 2 deletions(-) diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c index a6caa1e7b5..f762eb4a6e 100644 --- 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/cxl/cxl.h" #include "qemu/range.h" #include "qemu/error-report.h" #include "qemu/module.h" @@ -56,6 +57,16 @@ DECLARE_INSTANCE_CHECKER(PXBDev, PXB_DEV, DECLARE_INSTANCE_CHECKER(PXBDev, PXB_PCIE_DEV, TYPE_PXB_PCIE_DEVICE) +#define TYPE_PXB_CXL_DEVICE "pxb-cxl" +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; @@ -68,6 +79,11 @@ struct PXBDev { static PXBDev *convert_to_pxb(PCIDevice *dev) { + /* A CXL PXB's parent bus is PCIe, so the normal check won't work */ + if (object_dynamic_cast(OBJECT(dev), TYPE_PXB_CXL_DEVICE)) { + return PXB_CXL_DEV(dev); + } + return pci_bus_is_express(pci_get_bus(dev)) ? PXB_PCIE_DEV(dev) : PXB_DEV(dev); } @@ -112,11 +128,20 @@ static const TypeInfo pxb_pcie_bus_info = { .class_init = pxb_bus_class_init, }; +static const TypeInfo pxb_cxl_bus_info = { + .name = TYPE_PXB_CXL_BUS, + .parent = TYPE_CXL_BUS, + .instance_size = sizeof(PXBBus), + .class_init = pxb_bus_class_init, +}; + static const char *pxb_host_root_bus_path(PCIHostState *host_bridge, PCIBus *rootbus) { - PXBBus *bus = pci_bus_is_express(rootbus) ? - PXB_PCIE_BUS(rootbus) : PXB_BUS(rootbus); + PXBBus *bus = pci_bus_is_cxl(rootbus) ? + PXB_CXL_BUS(rootbus) : + pci_bus_is_express(rootbus) ? PXB_PCIE_BUS(rootbus) : + PXB_BUS(rootbus); snprintf(bus->bus_path, 8, "0000:%02x", pxb_bus_num(rootbus)); return bus->bus_path; @@ -218,6 +243,10 @@ static int pxb_map_irq_fn(PCIDevice *pci_dev, int pin) return pin - PCI_SLOT(pxb->devfn); } +static void pxb_dev_reset(DeviceState *dev) +{ +} + static gint pxb_compare(gconstpointer a, gconstpointer b) { const PXBDev *pxb_a = a, *pxb_b = b; @@ -389,13 +418,66 @@ 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->is_enabled) { + error_setg(errp, "Machine does not have cxl=on"); + return; + } + + pxb_dev_realize_common(dev, CXL, errp); + pxb_dev_reset(DEVICE(dev)); +} + +static void pxb_cxl_dev_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + PCIDeviceClass *k = PCI_DEVICE_CLASS(klass); + + k->realize = pxb_cxl_dev_realize; + k->exit = pxb_dev_exitfn; + /* + * XXX: These types of bridges don't actually show up in the hierarchy so + * vendor, device, class, etc. ids are intentionally left out. + */ + + dc->desc = "CXL Host Bridge"; + device_class_set_props(dc, pxb_dev_properties); + set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories); + + /* Host bridges aren't hotpluggable. FIXME: spec reference */ + dc->hotpluggable = false; + dc->reset = pxb_dev_reset; +} + +static const TypeInfo pxb_cxl_dev_info = { + .name = TYPE_PXB_CXL_DEVICE, + .parent = TYPE_PCI_DEVICE, + .instance_size = sizeof(PXBDev), + .class_init = pxb_cxl_dev_class_init, + .interfaces = + (InterfaceInfo[]){ + { INTERFACE_CONVENTIONAL_PCI_DEVICE }, + {}, + }, +}; + static void pxb_register_types(void) { type_register_static(&pxb_bus_info); type_register_static(&pxb_pcie_bus_info); + type_register_static(&pxb_cxl_bus_info); type_register_static(&pxb_host_info); type_register_static(&pxb_dev_info); type_register_static(&pxb_pcie_dev_info); + type_register_static(&pxb_cxl_dev_info); } type_init(pxb_register_types) diff --git a/hw/pci/pci.c b/hw/pci/pci.c index eb884adef9..6c0656f604 100644 --- a/hw/pci/pci.c +++ b/hw/pci/pci.c @@ -228,6 +228,12 @@ static const TypeInfo pcie_bus_info = { .class_init = pcie_bus_class_init, }; +static const TypeInfo cxl_bus_info = { + .name = TYPE_CXL_BUS, + .parent = TYPE_PCIE_BUS, + .class_init = pcie_bus_class_init, +}; + static PCIBus *pci_find_bus_nr(PCIBus *bus, int bus_num); static void pci_update_mappings(PCIDevice *d); static void pci_irq_handler(void *opaque, int irq_num, int level); @@ -2946,6 +2952,7 @@ static void pci_register_types(void) { type_register_static(&pci_bus_info); type_register_static(&pcie_bus_info); + type_register_static(&cxl_bus_info); type_register_static(&conventional_pci_interface_info); type_register_static(&cxl_interface_info); type_register_static(&pcie_interface_info); diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h index 98f0d1b844..44dacfa224 100644 --- a/include/hw/pci/pci.h +++ b/include/hw/pci/pci.h @@ -408,6 +408,7 @@ typedef PCIINTxRoute (*pci_route_irq_fn)(void *opaque, int pin); #define TYPE_PCI_BUS "PCI" OBJECT_DECLARE_TYPE(PCIBus, PCIBusClass, PCI_BUS) #define TYPE_PCIE_BUS "PCIE" +#define TYPE_CXL_BUS "CXL" typedef void (*pci_bus_dev_fn)(PCIBus *b, PCIDevice *d, void *opaque); typedef void (*pci_bus_fn)(PCIBus *b, void *opaque); @@ -770,6 +771,11 @@ static inline void pci_irq_pulse(PCIDevice *pci_dev) pci_irq_deassert(pci_dev); } +static inline int pci_is_cxl(const PCIDevice *d) +{ + return d->cap_present & QEMU_PCIE_CAP_CXL; +} + static inline int pci_is_express(const PCIDevice *d) { return d->cap_present & QEMU_PCI_CAP_EXPRESS; diff --git a/scripts/device-crash-test b/scripts/device-crash-test index 4bfc68c008..a203b3fdea 100755 --- a/scripts/device-crash-test +++ b/scripts/device-crash-test @@ -93,6 +93,7 @@ ERROR_RULE_LIST = [ {'device':'pci-bridge', 'expected':True}, # Bridge chassis not specified. Each bridge is required to be assigned a unique chassis id > 0. {'device':'pci-bridge-seat', 'expected':True}, # Bridge chassis not specified. Each bridge is required to be assigned a unique chassis id > 0. {'device':'pxb', 'expected':True}, # Bridge chassis not specified. Each bridge is required to be assigned a unique chassis id > 0. + {'device':'pxb-cxl', 'expected':True}, # pxb-cxl devices cannot reside on a PCI bus. {'device':'scsi-block', 'expected':True}, # drive property not set {'device':'scsi-generic', 'expected':True}, # drive property not set {'device':'scsi-hd', 'expected':True}, # drive property not set