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With QEMU older than 2.9.0 libvirt uses CPUID instruction to determine what CPU features are supported on the host. This was later used when checking compatibility of guest CPUs. Since QEMU 2.9.0 we ask QEMU for the host CPU data. But the two methods we use usually provide disjoint sets of CPU features because QEMU/KVM does not support all features provided by the host CPU and on the other hand it can enable some feature even if the host CPU does not support them. So if there is a domain which requires a CPU features disabled by QEMU/KVM, libvirt will refuse to start it with QEMU > 2.9.0 as its guest CPU is incompatible with the host CPU data we got from QEMU. But such domain would happily start on older QEMU (of course, the features would be missing the guest CPU). To fix this regression, we need to combine both CPU feature sets when checking guest CPU compatibility. https://bugzilla.redhat.com/show_bug.cgi?id=1439933 Signed-off-by: Jiri Denemark <jdenemar@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
* phyp/ - IBM Power Hypervisor using CLI tools over SSH
* qemu/ - QEMU / KVM using qemu CLI/monitor
* remote/ - Generic libvirt native RPC client
* test/ - A "mock" driver for testing
* uml/ - User Mode Linux
* vbox/ - Virtual Box using native API
* vmware/ - VMware Workstation and Player using the vmrun tool
* xen/ - Xen using hypercalls, XenD SEXPR & XenStore
* xenapi/ - Xen using libxenserver
Finally some secondary drivers that are shared for several HVs.
Currently these are used by LXC, OpenVZ, QEMU, UML and Xen drivers.
The ESX, Hyper-V, Power Hypervisor, 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