From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: Using signals to communicate two Qemu processes Date: Sun, 14 Dec 2008 00:21:27 +0200 Message-ID: <49443567.40609@redhat.com> References: <18C018878FB0244EB71B7FE328978A320F9FDA4C@rrsmsx503.amr.corp.intel.com> Reply-To: dlaor@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "kvm@vger.kernel.org" To: "Passera, Pablo R" Return-path: Received: from mx2.redhat.com ([66.187.237.31]:33583 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbYLMWVO (ORCPT ); Sat, 13 Dec 2008 17:21:14 -0500 In-Reply-To: <18C018878FB0244EB71B7FE328978A320F9FDA4C@rrsmsx503.amr.corp.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: Passera, Pablo R wrote: > Hi all, > I am trying to communicate two VMs using a virtio driver. Onc= e a data is moved to the driver I want to notify the other Qemu process= that there is new data available in the buffer. I was thinking about u= sing linux signals to synchronize both processes but when I register my= SIGUSR1 handler in Qemu I am seeing an strange behavior. After startin= g the VM and Linux gets loaded, Qemu is receiving SIGUSR2 at a regular = time period. Looking a little bit at the code I realize that signals ar= e being used for other purposes in Qemu, however, SIGUSR1 is not used. = Is it possible to use signals to synchronize these processes or should = I think about using a different mechanism? > > =20 SIGUSR2 is used as aio completion signal. You can use SIGUSR1 but you=20 need to know what you're doing (some threads block signals). Better fit would be a pipe. The vcpu > Thanks, > > Pablo P=E1ssera > Intel - Software Innovation Pathfinding Group > Cordoba - Argentina > Phone: +54 351 526 5611 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > =20