From 38a778aa1899b9c6cf3e300a02782c9b78c547ab Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Wed, 9 Feb 2011 15:11:28 +0100 Subject: [PATCH] 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: Jan Kiszka Signed-off-by: Avi Kivity --- Documentation/kvm/locking.txt | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/kvm/locking.txt diff --git a/Documentation/kvm/locking.txt b/Documentation/kvm/locking.txt new file mode 100644 index 000000000000..3b4cd3bf5631 --- /dev/null +++ b/Documentation/kvm/locking.txt @@ -0,0 +1,25 @@ +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. -- 2.20.1