| 1234567891011121314151617181920212223242526272829303132 |
- 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.
|
