[PATCH] KVM: Add documentation for kvm->srcu lock

[PATCH] KVM: Add documentation for kvm->srcu lock

[Thomas Huth]

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: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
 Documentation/virtual/kvm/locking.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/virtual/kvm/locking.txt b/Documentation/virtual/kvm/locking.txt
index 41b7ac9..a9f366e 100644
--- a/Documentation/virtual/kvm/locking.txt
+++ b/Documentation/virtual/kvm/locking.txt
@@ -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.
-- 
1.8.1.4

Re: [PATCH] KVM: Add documentation for kvm->srcu lock

[Paolo Bonzini]

Il 09/09/2013 17:32, Thomas Huth ha scritto:
> 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: Thomas Huth <thuth@linux.vnet.ibm.com>
> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
> ---
>  Documentation/virtual/kvm/locking.txt | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/virtual/kvm/locking.txt b/Documentation/virtual/kvm/locking.txt
> index 41b7ac9..a9f366e 100644
> --- a/Documentation/virtual/kvm/locking.txt
> +++ b/Documentation/virtual/kvm/locking.txt
> @@ -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.
> 

Applied to kvm/queue for 3.12, thanks.