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Commit 519192aa authored by Thomas Huth's avatar Thomas Huth Committed by Paolo Bonzini
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KVM: Add documentation for kvm->srcu lock 

This patch documents the kvm->srcu lock (using the information from
a mail which has been posted by Marcelo Tosatti to the kvm mailing
list some months ago, see the following URL for details:
http://www.mail-archive.com/kvm@vger.kernel.org/msg90040.html

 )

Signed-off-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 4a10c2ac

Documentation/virtual/kvm/locking.txt

+11 −0
Original line number Diff line number Diff line
@@ -151,3 +151,14 @@ Type: spinlock_t 
Arch:		any

Protects:	-shadow page/shadow tlb entry

Comment:	it is a spinlock since it is used in mmu notifier.



Name:		kvm->srcu

Type:		srcu lock

Arch:		any

Protects:	- kvm->memslots

		- kvm->buses

Comment:	The srcu read lock must be held while accessing memslots (e.g.

		when using gfn_to_* functions) and while accessing in-kernel

		MMIO/PIO address->device structure mapping (kvm->buses).

		The srcu index can be stored in kvm_vcpu->srcu_idx per vcpu

		if it is needed by multiple functions.