Avi Kivity wrote: >> >> 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. >> > > A race indeed, good catch. > > I think the race is only on the per_cpu(current_vmcs) variable, no? > The actual vmcs ptr (as loaded by vmptrld) is handled by the processor.
btw, I think the race is benign. if __vcpu_clear() wins, vcpu_load() gets to set current_vmcs and all is well. If vcpu_load() wins, __vcpu_clear() stomps on current_vmcs, but the only effect of that the next time vcpu_load() is called, it issues an unnecessary vmptrld. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- 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
