mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2025-02-05 11:19:29 +00:00
48341b025a
For finding the best matching CPU model for a given set of features while we don't know the CPU signature (i.e., when computing a baseline CPU model) we've been using a "shortest list of features" heuristics. This works well if new CPU models are supersets of older models, but that's not always the case. As a result it may actually select a new CPU model as a baseline while removing some features from it to make it compatible with older models. This is in general worse than using an old CPU model with a bunch of added features as a guest OS or apps may crash when using features that were disabled. On the other hand we don't want to end up with a very old model which would guarantee no disabled features as it could stop a guest OS or apps from using some features provided by the CPU because they would not expect them on such an old CPU. This patch changes the heuristics to something in between. Enabled and disabled features are counted separately so that a CPU model requiring some features to be disabled looks worse than a model with fewer disabled features even if its complete list of features is longer. The penalty given for each additional disabled feature gets bigger to make longer list of disabled features look even worse. https://bugzilla.redhat.com/show_bug.cgi?id=1851227 Signed-off-by: Jiri Denemark <jdenemar@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@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