From mboxrd@z Thu Jan 1 00:00:00 1970 From: Razvan Cojocaru Subject: Re: Hypervisor to dom0 communication Date: Tue, 13 Nov 2012 12:49:46 +0200 Message-ID: <50A225CA.2080705@gmail.com> References: <50A16639.2090209@gmail.com> <1352800791.7491.21.camel@zakaz.uk.xensource.com> <50A22044.6060608@gmail.com> <1352802973.7491.40.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1352802973.7491.40.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org >> OK, my immediate end-goal is real-time logging of hypervisor events via >> a dom0 userspace application. These events are always about a currently >> running virtual machine, and said virtual machine is paused at the time. >> The userspace tool should be immediately notified, so no polling. > > This is very like the ioreq model, where the domain (or maybe just the > vcpu, I'm not sure) is paused while qemu does its thing. > > What sort of events are we talking about here? A list of interesting registers that changed, that a page fault occured, things like that, occasionally containing some small string messages with extra information. Should be around 64 bytes or so. > The right thing to do here is for the userspace tool to communicate with > the toolstack (by whatever means) rather the hypervisor in order to > control the domains. That's what I was thinking too. > You might also find some inspiration for this sort of model in the > xenpaging and memshare code. Will look those things up, I appreciate the replies. Thanks, Razvan