On 11/05/2018 15:25, Andre Przywara wrote: > - I couldn't find any protection for the usage in > arch/powerpc/kvm/powerpc.c, but the call chain is quite convoluted > there, so I might have missed something. It would be good if someone > more familiar with this code would take a look. I also didn't find anything, I got up to kvmppc_handle_exit_pr in book3s_pr.c and kvmppc_handle_exit in booke.c, then the callers are assembly and I decided it's buggy. :) >> Adding the srcu_read_lock/unlock directly in kvm_arch_vcpu_ioctl_run and >> any other ioctls that need it is best, but in any case adding more pairs >> is safe because they can be nested. > > So I added a small wrapper around kvm_read_guest(), which takes and > drops the lock. Will send out the patch shortly. If powerpc needs it, I > am happy to provide this wrapper in kvm_main.c instead of some arm > header file instead. I think that risks having some performance impact, though perhaps mitigated by ARM having many virtual devices in the core. Moving it above would be better, to the equivalent of POWER's kvmppc_handle_exit* functions. Paolo
