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Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 10 Nov 2020 21:47:10 -0800 Ben Widawsky wrote: > 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. > > Upcoming patches will allow creating multiple host bridges. > > Signed-off-by: Ben Widawsky Hi Ben, Few minor things inline. Jonathan > --- > hw/pci-bridge/pci_expander_bridge.c | 67 ++++++++++++++++++++++++++++- > hw/pci/pci.c | 7 +++ > include/hw/pci/pci.h | 6 +++ > 3 files changed, 78 insertions(+), 2 deletions(-) > > diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c > index 88c45dc3b5..3a8d815231 100644 > --- a/hw/pci-bridge/pci_expander_bridge.c > +++ b/hw/pci-bridge/pci_expander_bridge.c > @@ -56,6 +56,10 @@ 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) > + > struct PXBDev { > /*< private >*/ > PCIDevice parent_obj; > @@ -67,6 +71,11 @@ 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); > } > @@ -111,11 +120,20 @@ 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); There comes a point where if / else is much more readable. > > snprintf(bus->bus_path, 8, "0000:%02x", pxb_bus_num(rootbus)); > return bus->bus_path; > @@ -380,13 +398,58 @@ static const TypeInfo pxb_pcie_dev_info = { > }, > }; > > +static void pxb_cxl_dev_realize(PCIDevice *dev, Error **errp) > +{ > + /* 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; > + } > + > + pxb_dev_realize_common(dev, CXL, errp); > +} > + > +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; > + k->vendor_id = PCI_VENDOR_ID_INTEL; > + k->device_id = 0xabcd; Just to check, is that an officially assigned device_id that we will never have a clash with? Nice ID to get if it is :) > + k->class_id = PCI_CLASS_BRIDGE_HOST; > + k->subsystem_vendor_id = PCI_VENDOR_ID_INTEL; > + > + 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; > +} > + > +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 db88788c4b..67eed889a4 100644 > --- a/hw/pci/pci.c > +++ b/hw/pci/pci.c > @@ -220,6 +220,12 @@ 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); > @@ -2847,6 +2853,7 @@ 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 4e6fd59fdd..52267ff69e 100644 > --- a/include/hw/pci/pci.h > +++ b/include/hw/pci/pci.h > @@ -405,6 +405,7 @@ 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" > > bool pci_bus_is_express(PCIBus *bus); > > @@ -753,6 +754,11 @@ 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;