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Commit 38a778aa authored by Jan Kiszka's avatar Jan Kiszka Committed by Marcelo Tosatti
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KVM: Start lock documentation 



The goal of this document shall be
- overview of all locks used in KVM core
- provide details on the scope of each lock
- explain the lock type, specifically of a raw spin locks
- provide a lock ordering guide

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 1260edbe

Documentation/kvm/locking.txt

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KVM Lock Overview

=================



1. Acquisition Orders

---------------------



(to be written)



2. Reference

------------



Name:		kvm_lock

Type:		raw_spinlock

Arch:		any

Protects:	- vm_list

		- hardware virtualization enable/disable

Comment:	'raw' because hardware enabling/disabling must be atomic /wrt

		migration.



Name:		kvm_arch::tsc_write_lock

Type:		raw_spinlock

Arch:		x86

Protects:	- kvm_arch::{last_tsc_write,last_tsc_nsec,last_tsc_offset}

		- tsc offset in vmcb

Comment:	'raw' because updating the tsc offsets must not be preempted.