On 12/07/2011 06:03 PM, Marcelo Tosatti wrote:

On Wed, Dec 07, 2011 at 05:24:59PM +0530, Raghavendra K T wrote:

quoted

On 12/07/2011 04:18 PM, Marcelo Tosatti wrote:
Yes you are right. It was potentially racy and it was harmful too!.
I had observed that it was stalling the CPU before I introduced
kicked flag.

But now,

vcpu->kicked = 1  ==>  kvm_make_request(KVM_REQ_UNHALT, vcpu); ==>

Ok, please use a more descriptive name, such as "pvlock_kicked" or
something.

Yes, pvlock_kicked seems good. 'll use same unless something else
flashes.

quoted

__vcpu_run() ==>  kvm_check_request(KVM_REQ_UNHALT, vcpu) ==>

vcpuN->mp_state = KVM_MP_STATE_RUNNABLE; so eventually we will end up
in RUNNABLE.

Also Avi pointed that, logically kvm_arch_vcpu_ioctl_set_mpstate should
be called only in vcpu thread, so after further debugging, I noticed
that,  setting vcpuN->mp_state = KVM_MP_STATE_RUNNABLE; is not
necessary.
I 'll remove that in the next patch. Thanks for pointing.

In fact you don't need kvm_arch_vcpu_ioctl_set_mpstate either, only the
new "kicked" flag.

True indeed, I meant the same.