From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59337) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VbtYo-0001Xi-1E for qemu-devel@nongnu.org; Thu, 31 Oct 2013 10:49:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VbtYg-0002Nt-NC for qemu-devel@nongnu.org; Thu, 31 Oct 2013 10:49:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27763) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VbtYg-0002Nk-EZ for qemu-devel@nongnu.org; Thu, 31 Oct 2013 10:49:14 -0400 Message-ID: <52726DE4.3090807@redhat.com> Date: Thu, 31 Oct 2013 08:49:08 -0600 From: Eric Blake MIME-Version: 1.0 References: <1377187852-11192-1-git-send-email-pbonzini@redhat.com> <20131024023903.GD16757@G08FNSTD100614.fnst.cn.fujitsu.com> <20131031143004.GA9948@redhat.com> <52726A0B.4080805@redhat.com> <20131031144729.GB9948@redhat.com> In-Reply-To: <20131031144729.GB9948@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="08ShfvVhSIfMPQaH9Wp5G9PLxfKL4s4sd" Subject: Re: [Qemu-devel] pvpanic plans? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: pkrempa@redhat.com, marcel.a@redhat.com, libvir-list@redhat.com, Hu Tao , qemu-devel@nongnu.org, armbru@redhat.com, rhod@redhat.com, kraxel@redhat.com, anthony@codemonkey.ws, Paolo Bonzini , lcapitulino@redhat.com, lersek@redhat.com, afaerber@suse.de This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --08ShfvVhSIfMPQaH9Wp5G9PLxfKL4s4sd Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 10/31/2013 08:47 AM, Michael S. Tsirkin wrote: >>> if (event & PVPANIC_PANICKED) { >>> panicked_mon_event("pause"); >>> - vm_stop(RUN_STATE_GUEST_PANICKED); >> >> Don't you still need to halt the guest on a panic event, for managemen= t >> to have a chance to choose what to do about the panic? >=20 > Guest can just call hlt to do this. Most guests do this on a panic > already. On the one hand, the fact that the guest already has to inform the host means we are already trusting the guest behavior on a panic. On the other hand, assuming that the guest will ALWAYS halt after triggering a panic is putting a lot more trust in the guest, compared to qemu explicitly halting the guest so that management has a chance to choose to dump the guest's state at the moment the panic was flagged. The biggest argument for either removing all auto-pvpanic, or reverting pvpanic altogether, is that no one seems to be actively using pvpanic in the field yet. I wish we could get more feedback from Fujitsu as the original patch authors on what they are looking for in a working solution, rather than repeatedly second-guessing everything downstream and delaying the eradication of the buggy behavior even longer. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --08ShfvVhSIfMPQaH9Wp5G9PLxfKL4s4sd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJScm3kAAoJEKeha0olJ0NqfX0H/0uIIs/BPS+nkLdUOVKc57qg zaee7l04+zO9+oryteUEF+EPFfmxkjoAbRuXJHCnfexf/G+qwzwOOmb6ql1CSAWv 7Faed59MNfztzbwO5F9KN1WX34xIVdz9PMmPR/q4vOCoUD2dqNgf3X8t63N/5hup b4qNpjo/Jtq650E6kEkhwuN04Ca20s7PBIqyPdcZQjnEz97j0H8otoQmsczXXBlz Pgkhg0mXIplzxscONtSVJW08FHyuxeHW59GSrAiY2AFy6w/pMG+qxCo6+SdXnF/E LfazrAJip/Fr5WHWdVr5BW2pO5kYKEtUvDvYaagsuQ/L5/To20sT/bMsZ49TfJM= =hWcy -----END PGP SIGNATURE----- --08ShfvVhSIfMPQaH9Wp5G9PLxfKL4s4sd--