From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 2/4] KVM: Rework VCPU state writeback API Date: Tue, 02 Mar 2010 09:00:04 +0100 Message-ID: <4B8CC584.1060106@web.de> References: <2257cac7474705fc35d74fcdff0566fb7dc0770e.1267467030.git.jan.kiszka@siemens.com> <20100302001415.GA22627@amt.cnet> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigD10705819BBE04E84D1F4026" Cc: Avi Kivity , kvm@vger.kernel.org, qemu-devel@nongnu.org To: Marcelo Tosatti Return-path: Received: from fmmailgate02.web.de ([217.72.192.227]:32965 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753579Ab0CBIAP (ORCPT ); Tue, 2 Mar 2010 03:00:15 -0500 In-Reply-To: <20100302001415.GA22627@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigD10705819BBE04E84D1F4026 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Marcelo Tosatti wrote: > On Mon, Mar 01, 2010 at 07:10:30PM +0100, Jan Kiszka wrote: >> This grand cleanup drops all reset and vmsave/load related >> synchronization points in favor of four(!) generic hooks: >> >> - cpu_synchronize_all_states in qemu_savevm_state_complete >> (initial sync from kernel before vmsave) >> - cpu_synchronize_all_post_init in qemu_loadvm_state >> (writeback after vmload) >> - cpu_synchronize_all_post_init in main after machine init >> - cpu_synchronize_all_post_reset in qemu_system_reset >> (writeback after system reset) >> >> These writeback points + the existing one of VCPU exec after >> cpu_synchronize_state map on three levels of writeback: >> >> - KVM_PUT_RUNTIME_STATE (during runtime, other VCPUs continue to run) >> - KVM_PUT_RESET_STATE (on synchronous system reset, all VCPUs stoppe= d) >> - KVM_PUT_FULL_STATE (on init or vmload, all VCPUs stopped as well)= >> >> This level is passed to the arch-specific VCPU state writing function >> that will decide which concrete substates need to be written. That way= , >> no writer of load, save or reset functions that interact with in-kerne= l >> KVM states will ever have to worry about synchronization again. That >> also means that a lot of reasons for races, segfaults and deadlocks ar= e >> eliminated. >> >> cpu_synchronize_state remains untouched, just as Anthony suggested. We= >> continue to need it before reading or writing of VCPU states that are >> also tracked by in-kernel KVM subsystems. >> >> Consequently, this patch removes many cpu_synchronize_state calls that= >> are now redundant, just like remaining explicit register syncs. >> >> Signed-off-by: Jan Kiszka >=20 > Jan, >=20 > This patch breaks system reset of WinXP.32 install (more easily > reproducible without iothread enabled). >=20 > Screenshot attached. >=20 Strange - no issues with qemu-kvm? Any special command line switch? /me goes scrounging for some installation XP32 CD in the meantime... Jan --------------enigD10705819BBE04E84D1F4026 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iEYEARECAAYFAkuMxYsACgkQitSsb3rl5xT/4wCfSt8eZEyP+lJqC1213XO2dUeQ aIkAoK7xUt/+/J+uTkdM6t+yAdJdqTU8 =xKgn -----END PGP SIGNATURE----- --------------enigD10705819BBE04E84D1F4026--