[EMAIL PROTECTED] wrote: > On Thu, 2007-07-26 at 18:03 +0300, Avi Kivity wrote: >> Gregory Haskins wrote: >>> We need to provide locking around the current_vmcs/VMCS >>> interactions to protect against race conditions. >>> >>> >> >> Can you explain the race? > > Sure. It can happen with two VMs are running simultaneously. > Lets call > them VM-a and VM-b. Assume the scenario: VM-a is on CPU-x, gets > migrated to CPU-y, and VM-b gets scheduled in on CPU-x. There > is a race > on CPU-x with the VMCS handling logic between the VM-b process > context, and the IPI to execute the __vcpu_clear for VM-a.
I may miss something, why does that matter? __vcpu_clear will eventually get executed though it is a little bit delayed. vmclear will eventually dump internal state of VM-a VMCS to memory and VM-b get its own VMCS loaded. Here the point is vmclear has a parameter to identify which VM's VMCS to dump, not only a memory address. Jun, please correct me if I am wrong. > > Disabling interrupts was chosen as the sync-primitive, because the > code will always be on the CPU in question. > thx, eddie ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
