On Sun, Mar 10, 2013 at 03:53:54PM +0100, Paolo Bonzini wrote: > Il 10/03/2013 12:46, Gleb Natapov ha scritto: > > On Sat, Mar 09, 2013 at 07:48:33AM +0100, Paolo Bonzini wrote: > >> After receiving an INIT signal (either via the local APIC, or through > >> KVM_SET_MP_STATE), the bootstrap processor should reset immediately > >> and start execution at 0xfffffff0. Also, SIPIs have no effect on the > >> bootstrap processor. However, KVM currently does not differentiate > >> between the BSP and APs. > >> > > Userspace is capable of resetting vcpu by itself, so adding code to > > handle KVM_SET_MP_STATE(INIT) looks unnecessary to me. I think the > > simple patch below (not tested) should handle INIT for in-kernel irq chip > > and userspace does not need special handling for cpu reset. It already > > knows how to reset cpu on system_reset, so reseting only cpus should not > > be different. > > At least you'll need the last two hunks, moving the check for > KVM_MP_STATE_SIPI_RECEIVED before kvm_vcpu_block, but yes---something > like this could work. > I do not see why. kvm_vcpu_block() exits if vpu is in KVM_MP_STATE_SIPI_RECEIVED state. > However, it would effectively redefine the meaning of > KVM_MP_STATE_INIT_RECEIVED and KVM_MP_STATE_SIPI_RECEIVED, respectively > to KVM_MP_STATE_WAIT_FOR_SIPI and KVM_MP_STATE_RESETTING. I wasn't sure > if this is considered an API change (personally, I would treat it as one). > If it is kernel module internal it definitely is not API change. INIT/SIPI handling is a bit ad-hoc right now anyway as Jan noticed. For instance INIT does not really resets VCPU. Only after SIPI it is really reset, so KVM_MP_STATE_SIPI_RECEIVED is really KVM_MP_STATE_RESET_ME_RIGHT_NOW state. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
