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authorPeter Maydell <peter.maydell@linaro.org>2015-06-04 18:32:44 +0100
committerPeter Maydell <peter.maydell@linaro.org>2015-06-04 18:33:24 +0100
commitd6688ba17b934f20f5e8953dbaafc9408d8799c5 (patch)
tree88f5ea991ec6a037e578ef43fe2c40e0509f39f6 /docs
parent3b730f570c5872ceea2137848f1d4554d4847441 (diff)
parent309750fad51f17d1ec6195c5d8ad7d741596ddb6 (diff)
Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
pc, acpi, virtio, tpm This includes pxb support by Marcel, as well as multiple enhancements all over the place. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # gpg: Signature made Thu Jun 4 11:51:02 2015 BST using RSA key ID D28D5469 # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" * remotes/mst/tags/for_upstream: (28 commits) vhost: logs sharing hw/acpi: piix4_pm_init(): take fw_cfg object no more hw/acpi: move "etc/system-states" fw_cfg file from PIIX4 to core hw/acpi: acpi_pm1_cnt_init(): take "disable_s3" and "disable_s4" pc-dimm: don't assert if pc-dimm alignment != hotpluggable mem range size docs: Add PXB documentation apci: fix PXB behaviour if used with unsupported BIOS hw/pxb: add numa_node parameter hw/pci: add support for NUMA nodes hw/pxb: add map_irq func hw/pci: inform bios if the system has extra pci root buses hw/pci: introduce PCI Expander Bridge (PXB) hw/pci: removed 'rootbus nr is 0' assumption from qmp_pci_query hw/acpi: remove from root bus 0 the crs resources used by other buses. hw/acpi: add _CRS method for extra root busses hw/apci: add _PRT method for extra PCI root busses hw/acpi: add support for i440fx 'snooping' root busses hw/pci: extend PCI config access to support devices behind PXB hw/i386: query only for q35/pc when looking for pci host bridge hw/pci: made pci_bus_num a PCIBusClass method ... Conflicts: hw/i386/pc_piix.c Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
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+PCI EXPANDER BRIDGE (PXB)
+=========================
+
+Description
+===========
+PXB is a "light-weight" host bridge in the same PCI domain
+as the main host bridge whose purpose is to enable
+the main host bridge to support multiple PCI root buses.
+It is implemented only for i440fx and can be placed only
+on bus 0 (pci.0).
+
+As opposed to PCI-2-PCI bridge's secondary bus, PXB's bus
+is a primary bus and can be associated with a NUMA node
+(different from the main host bridge) allowing the guest OS
+to recognize the proximity of a pass-through device to
+other resources as RAM and CPUs.
+
+Usage
+=====
+A detailed command line would be:
+
+[qemu-bin + storage options]
+-m 2G
+-object memory-backend-ram,size=1024M,policy=bind,host-nodes=0,id=ram-node0 -numa node,nodeid=0,cpus=0,memdev=ram-node0
+-object memory-backend-ram,size=1024M,policy=bind,host-nodes=1,id=ram-node1 -numa node,nodeid=1,cpus=1,memdev=ram-node1
+-device pxb,id=bridge1,bus=pci.0,numa_node=1,bus_nr=4 -netdev user,id=nd-device e1000,bus=bridge1,addr=0x4,netdev=nd
+-device pxb,id=bridge2,bus=pci.0,numa_node=0,bus_nr=8,bus=pci.0 -device e1000,bus=bridge2,addr=0x3
+-device pxb,id=bridge3,bus=pci.0,bus_nr=40,bus=pci.0 -drive if=none,id=drive0,file=[img] -device virtio-blk-pci,drive=drive0,scsi=off,bus=bridge3,addr=1
+
+Here you have:
+ - 2 NUMA nodes for the guest, 0 and 1. (both mapped to the same NUMA node in host, but you can and should put it in different host NUMA nodes)
+ - a pxb host bridge attached to NUMA 1 with an e1000 behind it
+ - a pxb host bridge attached to NUMA 0 with an e1000 behind it
+ - a pxb host bridge not attached to any NUMA with a hard drive behind it.
+
+Limitations
+===========
+Please observe that we specified the bus "pci.0" for the second and third pxb.
+This is because when no bus is given, another pxb can be selected by QEMU as default bus,
+however, PXBs can be placed only under the root bus.
+
+Implementation
+==============
+The PXB is composed by:
+- HostBridge (TYPE_PXB_HOST)
+ The host bridge allows to register and query the PXB's rPCI root bus in QEMU.
+- PXBDev(TYPE_PXB_DEVICE)
+ It is a regular PCI Device that resides on the piix host-bridge bus and its bus uses the same PCI domain.
+ However, the bus behind is exposed through ACPI as a primary PCI bus and starts a new PCI hierarchy.
+ The interrupts from devices behind the PXB are routed through this device the same as if it were a
+ PCI-2-PCI bridge. The _PRT follows the i440fx model.
+- PCIBridgeDev(TYPE_PCI_BRIDGE_DEV)
+ Created automatically as part of init sequence.
+ When adding a device to PXB it is attached to the bridge for two reasons:
+ - Using the bridge will enable hotplug support
+ - All the devices behind the bridge will use bridge's IO/MEM windows compacting
+ the PCI address space.
+