From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E4EEC4CECD for ; Mon, 27 Apr 2020 19:10:15 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5CA1D20B1F for ; Mon, 27 Apr 2020 19:10:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="c837OH1d" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5CA1D20B1F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59180 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jT98w-0001dD-A7 for qemu-devel@archiver.kernel.org; Mon, 27 Apr 2020 15:10:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41768) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jT97t-0000gI-31 for qemu-devel@nongnu.org; Mon, 27 Apr 2020 15:09:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jT97o-0007tU-Hs for qemu-devel@nongnu.org; Mon, 27 Apr 2020 15:09:08 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:39017 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jT97o-0007tA-2j for qemu-devel@nongnu.org; Mon, 27 Apr 2020 15:09:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588014542; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jHIIlBZoZ2t/HVqolnuRfa1DqTM/PJSHham9OOL3aUc=; b=c837OH1dTCQXO9JA95R1Xsab0j9ipj+W+UaOgpHV0rOdH+aprEiNtSK5qpwE74vvzyC7Gq GGxSY9ej4XaghdXTmRHR7CVD87I8M7HXtkqGUYUzVaRY9BZ3ypwNdqOyK8dSBGj/KDz2PN NcoYIpAqv4B/7Skxv07DNDHSbkc0h9Q= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-413-Esbbb5nmMdG31XmCn5YabA-1; Mon, 27 Apr 2020 15:09:00 -0400 X-MC-Unique: Esbbb5nmMdG31XmCn5YabA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4D102835B40; Mon, 27 Apr 2020 19:08:59 +0000 (UTC) Received: from work-vm (ovpn-112-96.ams2.redhat.com [10.36.112.96]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F328C50F53; Mon, 27 Apr 2020 19:08:57 +0000 (UTC) Date: Mon, 27 Apr 2020 20:08:55 +0100 From: "Dr. David Alan Gilbert" To: Adalbert =?utf-8?B?TGF6xINy?= Subject: Re: [RFC PATCH v1 20/26] kvm: vmi: intercept live migration Message-ID: <20200427190855.GN2923@work-vm> References: <20200415005938.23895-1-alazar@bitdefender.com> <20200415005938.23895-21-alazar@bitdefender.com> MIME-Version: 1.0 In-Reply-To: <20200415005938.23895-21-alazar@bitdefender.com> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/27 02:05:28 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marian Rotariu , qemu-devel@nongnu.org, Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Adalbert Laz=C4=83r (alazar@bitdefender.com) wrote: > From: Marian Rotariu >=20 > It is possible that the introspection tool has made some changes inside > the introspected VM which can make the guest crash if the introspection > connection is suddenly closed. >=20 > When the live migration starts, for now, the introspection tool is > signaled to remove its hooks from the introspected VM. >=20 > CC: Juan Quintela > CC: "Dr. David Alan Gilbert" > Signed-off-by: Marian Rotariu > Signed-off-by: Adalbert Laz=C4=83r OK, so this isn't too intrusive to the migration code; and other than renaming 'start_live_migration_thread' to 'start_outgoing_migration_thread' I think I'd be OK with this, but it might depend what your overall aim is. For example, you might be better intercepting each migration_state change in your notifier, that's much finer grain than just the start of migration. The other thing I worry about is that there doesn't seem to be much guard against odd orderings of things - for example, what happens if the introspection client was to issue the INTERCEPT_MIGRATE command twice while a migration was already running? Or before an actual incoming channel connetion had happened? Dave > --- > accel/kvm/vmi.c | 31 +++++++++++++++++++++++++++---- > include/sysemu/vmi-intercept.h | 1 + > migration/migration.c | 18 +++++++++++++++--- > migration/migration.h | 2 ++ > 4 files changed, 45 insertions(+), 7 deletions(-) >=20 > diff --git a/accel/kvm/vmi.c b/accel/kvm/vmi.c > index 90906478b4..ea7191e48d 100644 > --- a/accel/kvm/vmi.c > +++ b/accel/kvm/vmi.c > @@ -21,6 +21,8 @@ > #include "chardev/char.h" > #include "chardev/char-fe.h" > #include "migration/vmstate.h" > +#include "migration/migration.h" > +#include "migration/misc.h" > =20 > #include "sysemu/vmi-intercept.h" > #include "sysemu/vmi-handshake.h" > @@ -58,6 +60,7 @@ typedef struct VMIntrospection { > int64_t vm_start_time; > =20 > Notifier machine_ready; > + Notifier migration_state_change; > bool created_from_command_line; > =20 > bool kvmi_hooked; > @@ -74,9 +77,11 @@ static const char *action_string[] =3D { > "suspend", > "resume", > "force-reset", > + "migrate", > }; > =20 > static bool suspend_pending; > +static bool migrate_pending; > =20 > #define TYPE_VM_INTROSPECTION "introspection" > =20 > @@ -88,6 +93,15 @@ static bool suspend_pending; > static Error *vm_introspection_init(VMIntrospection *i); > static void vm_introspection_reset(void *opaque); > =20 > +static void migration_state_notifier(Notifier *notifier, void *data) > +{ > + MigrationState *s =3D data; > + > + if (migration_has_failed(s)) { > + migrate_pending =3D false; > + } > +} > + > static void machine_ready(Notifier *notifier, void *data) > { > VMIntrospection *i =3D container_of(notifier, VMIntrospection, machi= ne_ready); > @@ -144,6 +158,9 @@ static void complete(UserCreatable *uc, Error **errp) > =20 > ic->uniq =3D i; > =20 > + i->migration_state_change.notify =3D migration_state_notifier; > + add_migration_state_change_notifier(&i->migration_state_change); > + > qemu_register_reset(vm_introspection_reset, i); > } > =20 > @@ -478,6 +495,9 @@ static void continue_with_the_intercepted_action(VMIn= trospection *i) > case VMI_INTERCEPT_SUSPEND: > vm_stop(RUN_STATE_PAUSED); > break; > + case VMI_INTERCEPT_MIGRATE: > + start_live_migration_thread(migrate_get_current()); > + break; > default: > error_report("VMI: %s: unexpected action %d", > __func__, i->intercepted_action); > @@ -571,9 +591,9 @@ static void chr_event_open(VMIntrospection *i) > { > Error *local_err =3D NULL; > =20 > - if (suspend_pending) { > - info_report("VMI: %s: too soon (suspend=3D%d)", > - __func__, suspend_pending); > + if (suspend_pending || migrate_pending) { > + info_report("VMI: %s: too soon (suspend=3D%d, migrate=3D%d)", > + __func__, suspend_pending, migrate_pending); > maybe_disable_socket_reconnect(i); > qemu_chr_fe_disconnect(&i->sock); > return; > @@ -608,7 +628,7 @@ static void chr_event_close(VMIntrospection *i) > cancel_unhook_timer(i); > cancel_handshake_timer(i); > =20 > - if (suspend_pending) { > + if (suspend_pending || migrate_pending) { > maybe_disable_socket_reconnect(i); > =20 > if (i->intercepted_action !=3D VMI_INTERCEPT_NONE) { > @@ -680,6 +700,9 @@ static bool record_intercept_action(VMI_intercept_com= mand action) > break; > case VMI_INTERCEPT_FORCE_RESET: > break; > + case VMI_INTERCEPT_MIGRATE: > + migrate_pending =3D true; > + break; > default: > return false; > } > diff --git a/include/sysemu/vmi-intercept.h b/include/sysemu/vmi-intercep= t.h > index ef591b49e7..b4a9a3faa7 100644 > --- a/include/sysemu/vmi-intercept.h > +++ b/include/sysemu/vmi-intercept.h > @@ -15,6 +15,7 @@ typedef enum { > VMI_INTERCEPT_SUSPEND, > VMI_INTERCEPT_RESUME, > VMI_INTERCEPT_FORCE_RESET, > + VMI_INTERCEPT_MIGRATE, > } VMI_intercept_command; > =20 > bool vm_introspection_intercept(VMI_intercept_command ic, Error **errp); > diff --git a/migration/migration.c b/migration/migration.c > index 187ac0410c..222037d739 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -55,6 +55,8 @@ > #include "qemu/queue.h" > #include "multifd.h" > =20 > +#include "sysemu/vmi-intercept.h" > + > #define MAX_THROTTLE (32 << 20) /* Migration transfer speed thrott= ling */ > =20 > /* Amount of time to allocate to each "chunk" of bandwidth-throttled > @@ -3471,6 +3473,13 @@ static void *migration_thread(void *opaque) > return NULL; > } > =20 > +void start_live_migration_thread(MigrationState *s) > +{ > + qemu_thread_create(&s->thread, "live_migration", migration_thread, s= , > + QEMU_THREAD_JOINABLE); > + s->migration_thread_running =3D true; > +} > + > void migrate_fd_connect(MigrationState *s, Error *error_in) > { > Error *local_err =3D NULL; > @@ -3534,9 +3543,12 @@ void migrate_fd_connect(MigrationState *s, Error *= error_in) > migrate_fd_cleanup(s); > return; > } > - qemu_thread_create(&s->thread, "live_migration", migration_thread, s= , > - QEMU_THREAD_JOINABLE); > - s->migration_thread_running =3D true; > + > + if (vm_introspection_intercept(VMI_INTERCEPT_MIGRATE, &error_in)) { > + return; > + } > + > + start_live_migration_thread(s); > } > =20 > void migration_global_dump(Monitor *mon) > diff --git a/migration/migration.h b/migration/migration.h > index 507284e563..eb5668e1f2 100644 > --- a/migration/migration.h > +++ b/migration/migration.h > @@ -263,6 +263,8 @@ struct MigrationState > uint8_t clear_bitmap_shift; > }; > =20 > +void start_live_migration_thread(MigrationState *s); > + > void migrate_set_state(int *state, int old_state, int new_state); > =20 > void migration_fd_process_incoming(QEMUFile *f, Error **errp); >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK