Re: [Qemu-devel] About SIG_IPI handler

[Paolo Bonzini]

Il 19/04/2014 07:24, Shiru Ren ha scritto:
> Thanks for your answer. It really helped me a lot. However, it cloud be
> really helpful if you cloud explain how the SIG_IPI signal causes the
> CPU thread to exit the vcpu thread in KVM mode. Is it like an interrupt,
> causes a VM exit immediately? Or KVM just ignore it till a VM exit happens.

Yes, sending the signal causes the kernel to send an IPI to the 
processor running the VCPU thread (a hardware-level one, not the "soft" 
SIG_IPI concept).  The IPI causes a VM exit to happen immediately.

Paolo