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Xen only supports a single type of PCI hostdev assignment, so it is superfluous to have <driver name='xen'/> peppered throughout the config. It *is* necessary to have the driver type explicitly set in the hostdev object before calling into the hypervisor-agnostic "hostdev manager" though (otherwise the hostdev manager doesn't know whether it should do Xen-specific setup, or VFIO-specific setup). Historically, the Xen driver has checked for "default" driver name (i.e. not set in the XML), and set it to "xen', during the XML postparse, thus guaranteeing that it will be set by the time the object is sent to the hostdev manager at runtime, but also setting it so early that a simple round-trip of parse-format results in the XML always containing an explicit <driver name='xen'/>, even if that wasn't specified in the original XML. The QEMU driver *doesn't* set driver.name during postparse though; instead, it waits until domain startup time (or device attach time for hotplug), and sets the driver.name then. The result is that a parse-format round trip of the XML in the QEMU driver *doesn't* add in the <driver name='vfio'/>. This patch modifies the Xen driver to behave similarly to the QEMU driver - the PostParse just checks for a driver.name that isn't supported by the Xen driver, and any explicit setting to "xen" is deferred until domain runtime rather than during the postparse, thus Xen domain XML also doesn't get extraneous <driver name='xen'/>. This delayed setting of driver.name of course results in slightly different xml2xml parse-format results, so the unit test data is modified accordingly. Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
libvirt library code README
===========================
The directory provides the bulk of the libvirt codebase. Everything
except for the libvirtd daemon and client tools. The build uses a
large number of libtool convenience libraries - one for each child
directory, and then links them together for the final libvirt.so,
although some bits get linked directly to libvirtd daemon instead.
The files directly in this directory are supporting the public API
entry points & data structures.
There are two core shared modules to be aware of:
* util/ - a collection of shared APIs that can be used by any
code. This directory is always in the include path
for all things built
* conf/ - APIs for parsing / manipulating all the official XML
files used by the public API. This directory is only
in the include path for driver implementation modules
* vmx/ - VMware VMX config handling (used by esx/ and vmware/)
Then there are the hypervisor implementations:
* bhyve - bhyve - The BSD Hypervisor
* esx/ - VMware ESX and GSX support using vSphere API over SOAP
* hyperv/ - Microsoft Hyper-V support using WinRM
* lxc/ - Linux Native Containers
* openvz/ - OpenVZ containers using cli tools
* qemu/ - QEMU / KVM using qemu CLI/monitor
* remote/ - Generic libvirt native RPC client
* test/ - A "mock" driver for testing
* vbox/ - Virtual Box using native API
* vmware/ - VMware Workstation and Player using the vmrun tool
* xen/ - Xen using hypercalls, XenD SEXPR & XenStore
Finally some secondary drivers that are shared for several HVs.
Currently these are used by LXC, OpenVZ, QEMU and Xen drivers.
The ESX, Hyper-V, Remote, Test & VirtualBox drivers all
implement the secondary drivers directly
* cpu/ - CPU feature management
* interface/ - Host network interface management
* network/ - Virtual NAT networking
* nwfilter/ - Network traffic filtering rules
* node_device/ - Host device enumeration
* secret/ - Secret management
* security/ - Mandatory access control drivers
* storage/ - Storage management drivers
Since both the hypervisor and secondary drivers can be built as
dlopen()able modules, it is *FORBIDDEN* to have build dependencies
between these directories. Drivers are only allowed to depend on
the public API, and the internal APIs in the util/ and conf/
directories