From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:38228) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T10dE-0000eu-Ph for qemu-devel@nongnu.org; Mon, 13 Aug 2012 15:48:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T10dC-0003my-34 for qemu-devel@nongnu.org; Mon, 13 Aug 2012 15:48:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8420) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T10dB-0003me-RG for qemu-devel@nongnu.org; Mon, 13 Aug 2012 15:48:54 -0400 Message-ID: <50295A17.8010404@redhat.com> Date: Mon, 13 Aug 2012 13:48:39 -0600 From: Eric Blake MIME-Version: 1.0 References: <5021D235.4050800@cn.fujitsu.com> <20120813182132.GB25268@amt.cnet> In-Reply-To: <20120813182132.GB25268@amt.cnet> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enigF2EF96AD58E57E8BEB7FB44F" Subject: Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcelo Tosatti Cc: Gleb Natapov , Jan Kiszka , qemu-devel , "linux-kernel@vger.kernel.org" , Avi Kivity , kvm list , KAMEZAWA Hiroyuki This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigF2EF96AD58E57E8BEB7FB44F Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 08/13/2012 12:21 PM, Marcelo Tosatti wrote: > On Wed, Aug 08, 2012 at 10:43:01AM +0800, Wen Congyang wrote: >> We can know the guest is panicked when the guest runs on xen. >> But we do not have such feature on kvm. >> >> Another purpose of this feature is: management app(for example: >> libvirt) can do auto dump when the guest is panicked. If management >> app does not do auto dump, the guest's user can do dump by hand if >> he sees the guest is panicked. >> >> We have three solutions to implement this feature: >> 1. use vmcall >> 2. use I/O port >> 3. use virtio-serial. >> >> We have decided to avoid touching hypervisor. The reason why I choose >> choose the I/O port is: >> 1. it is easier to implememt >> 2. it does not depend any virtual device >> 3. it can work when starting the kernel >=20 > How about searching for the "Kernel panic - not syncing" string=20 > in the guests serial output? Say libvirtd could take an action upon > that? >=20 > Advantages: > - It works for all architectures. > - It does not depend on any virtual device. But it _does_ depend on a serial console, and furthermore requires libvirt to tee the serial console (right now, libvirt can treat the console as an opaque pass-through to the end user, but if you expect libvirt to parse the serial console for a particular string, you've lost some efficiency). > - It works as early as serial console output does (panics before > that should be rare). > - It allows you to see why the guest panicked. I think your arguments for a serial console have already been made and refuted in earlier versions of this patch series, which is WHY this series is still applicable. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enigF2EF96AD58E57E8BEB7FB44F Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJQKVoYAAoJEKeha0olJ0NqosQH+gKrPqkuriJCiuuY5XQe1DMo Bv+nUptgx3sW8WoXt8HGvA+wmfpFZPtGYlxMB1axapIAeYaw27u6YzQnVJGxliZH hRhAEexKlfFKadeM4r5A8cb7b1mbs5EnWfklN5UoxNhSDgYclb6b0nJZmgFUVRYi vmmc86JN0mSl1O8fNB1gxYx0jCKNvcOsZe+1jbADuGcSBWuAIicyzpAnr7lWWeoc 9GU1H2FfM7kJfO5LXPtz3mG5OIGvITBixkUFFnB/i4mU+jy5OVFpQQ50x3ZD+OUt RMlBWlW4k8w/QkaaixysD1Xg84OroOCmsiiRpUmUUdKD3E9n57wo6cK4JRzI5Ck= =OVM5 -----END PGP SIGNATURE----- --------------enigF2EF96AD58E57E8BEB7FB44F--