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authorThomas Huth <thuth@linux.vnet.ibm.com>2013-09-09 17:32:56 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2013-09-24 19:12:12 +0200
commit519192aaae38e24d6b32d3d55d791fe294981185 (patch)
treed813696b9b6b1837b7396d399bd6283d3a1e7da7 /Documentation/virtual/kvm/locking.txt
parent4a10c2ac2f368583138b774ca41fac4207911983 (diff)
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: Thomas Huth <thuth@linux.vnet.ibm.com> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virtual/kvm/locking.txt')
-rw-r--r--Documentation/virtual/kvm/locking.txt11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/locking.txt b/Documentation/virtual/kvm/locking.txt
index 41b7ac9884b5..a9f366e73c8e 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.