Hi, Following my previous post about implementing PCI Passthrough on CloudStack (KVM), I have taken Edison Su’s and others’ comments into account and came up with an improved design.
Because the devices available at each agent may be different, the available devices for passthrough are now configured at the agent configuration file (/etc/cloudstack/agent/agent.properties). Configuration is a comma separated list of available PCI devices and its given name. pci.devices=28:00.1|10GE,28:00.2|10GE,28:00.3|10GE,28:00.4|10GE,28:00.5|10GE,28:00.6|10GE,28:00.7|10GE,28:01.0|10GE At agent startup, the list of PCI devices is parsed and sent together with StartupRoutingCommand (in a new field, not in details). The management server then stores it in a new table “op_host_pci_devices”. If a device is added, removed, or renamed, the table is updated accordingly. The current schema has the following fields id (auto-increment) host_id (host that this device belongs to) name (given name of the PCI device) domain (PCI ID - domain) bus (PCI ID - bus) slot (PCI ID - slot) function (PCI ID - function) instance_id (ID of the VM using the PCI device, NULL if not in use) The “name” of the PCI device is what is used to assign a device. In a compute offering, the user can specify the name of one or more PCI devices (as a comma-separated list) and CloudStack will find a host with the PCI device of the specified name available and assign it. A new manager, PciDeviceManager, is then created to handle the allocation of PCI device. The manager implements StateListener and assigns PCI devices on state change to “starting” and also release the devices VM stop. First fit allocator and first fit planner are also modified to check for PCI device availability accordingly. For migration, there are 2 approaches. The first approach is to forbid migration and is straightforward. The second approach is to PCI Hotplug to detach the device, migrate and attach it again at the other end. This will interrupt whatever is using the device on the VM. However, it may be desirable for networking devices where the VM can use a bonding device to channel network traffic through a standard virtualized network device while the PCI Passthrough device is down. The design mentioned here (including detach-attach migration) has been implemented in code and is working. Again, comments and suggestions are welcomed. Best Regards, Pawit
