mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 00:48:50 +00:00
2f5947dfca
Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories. We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory. Fix up the documentation
to match that.
Fixes: ed16648eb5 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
35 lines
1.5 KiB
ReStructuredText
35 lines
1.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
|
|
============
|
|
Paravirt_ops
|
|
============
|
|
|
|
Linux provides support for different hypervisor virtualization technologies.
|
|
Historically different binary kernels would be required in order to support
|
|
different hypervisors, this restriction was removed with pv_ops.
|
|
Linux pv_ops is a virtualization API which enables support for different
|
|
hypervisors. It allows each hypervisor to override critical operations and
|
|
allows a single kernel binary to run on all supported execution environments
|
|
including native machine -- without any hypervisors.
|
|
|
|
pv_ops provides a set of function pointers which represent operations
|
|
corresponding to low level critical instructions and high level
|
|
functionalities in various areas. pv-ops allows for optimizations at run
|
|
time by enabling binary patching of the low-ops critical operations
|
|
at boot time.
|
|
|
|
pv_ops operations are classified into three categories:
|
|
|
|
- simple indirect call
|
|
These operations correspond to high level functionality where it is
|
|
known that the overhead of indirect call isn't very important.
|
|
|
|
- indirect call which allows optimization with binary patch
|
|
Usually these operations correspond to low level critical instructions. They
|
|
are called frequently and are performance critical. The overhead is
|
|
very important.
|
|
|
|
- a set of macros for hand written assembly code
|
|
Hand written assembly codes (.S files) also need paravirtualization
|
|
because they include sensitive instructions or some of code paths in
|
|
them are very performance critical.
|