From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Webb Subject: Re: qemu-kvm guest which won't 'cont' (emulation failure?) Date: Mon, 24 Oct 2011 11:58:27 +0100 Message-ID: <20111024105826.GT9917@arachsys.com> References: <20111024100037.GS9917@arachsys.com> <4EA54104.7000001@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org To: Kevin Wolf Return-path: Content-Disposition: inline In-Reply-To: <4EA54104.7000001@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org Kevin Wolf writes: > Am 24.10.2011 12:00, schrieb Chris Webb: > > I have qemu monitor access and can even strace the relevant qemu process if > > necessary: is it possible to use this to diagnose what's caused this guest > > to stop, e.g. the unsupported instruction if it's an emulation failure? > > Another common cause for stopped VMs are I/O errors, for example writes > to a sparse image when the disk is full. This guest are backed by LVM LVs so I don't think they can return EFULL, but I could imagine read errors, so I've just done a trivial test to make sure I can read them end-to-end: 0015# dd if=/dev/mapper/guest\:e549f8e1-4c0e-4dea-826a-e4b877282c07\:ide\:0\:0 of=/dev/null bs=1M 3136+0 records in 3136+0 records out 3288334336 bytes (3.3 GB) copied, 20.898 s, 157 MB/s 0015# dd if=/dev/mapper/guest\:e549f8e1-4c0e-4dea-826a-e4b877282c07\:ide\:0\:1 of=/dev/null bs=1M 276+0 records in 276+0 records out 289406976 bytes (289 MB) copied, 1.85218 s, 156 MB/s Is there any way to ask qemu why a guest has stopped, so I can distinguish IO problems from emulation problems from anything else? Cheers, Chris.