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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 22C6DC282CB for ; Tue, 5 Feb 2019 05:44:41 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 EBDA32081B for ; Tue, 5 Feb 2019 05:44:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="MysyApm/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBDA32081B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43ttnK5NZGzDqMH for ; Tue, 5 Feb 2019 16:44:37 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43ttfM3KnJzDqKZ for ; Tue, 5 Feb 2019 16:38:35 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="MysyApm/"; dkim-atps=neutral Received: by ozlabs.org (Postfix, from userid 1007) id 43ttfM1Kqsz9sMM; Tue, 5 Feb 2019 16:38:34 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1549345115; bh=tRJ4W+pocH8UYPA9FrXTgJwvR1lfbqse6K/bIprSmbY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MysyApm/yDPuP4msJsbA9ROpso6xTvEiakRFq2jHhBX46sNasR6pE+GsvqrGAh3vt oG8daEHXEZnDasTMV+Ixan/cF4wxNeQKeZkMYdYsrcOPddWp6fiF3yXCwEvyZhVv3D CXMGCRazD5q0bOdA8fGgwKRABabuFi3uR116WeqQ= Date: Tue, 5 Feb 2019 16:30:58 +1100 From: David Gibson To: =?iso-8859-1?Q?C=E9dric?= Le Goater Subject: Re: [PATCH 14/19] KVM: PPC: Book3S HV: add a control to make the XIVE EQ pages dirty Message-ID: <20190205053058.GF22661@umbus.fritz.box> References: <20190107184331.8429-1-clg@kaod.org> <20190107184331.8429-15-clg@kaod.org> <20190204051833.GG1927@umbus.fritz.box> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="+jhVVhN62yS6hEJ8" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, Paul Mackerras , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" --+jhVVhN62yS6hEJ8 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 04, 2019 at 04:46:00PM +0100, C=E9dric Le Goater wrote: > On 2/4/19 6:18 AM, David Gibson wrote: > > On Mon, Jan 07, 2019 at 07:43:26PM +0100, C=E9dric Le Goater wrote: > >> When the VM is stopped in a migration sequence, the sources are masked > >> and the XIVE IC is synced to stabilize the EQs. When done, the KVM > >> ioctl KVM_DEV_XIVE_SAVE_EQ_PAGES is called to mark dirty the EQ pages. > >> > >> The migration can then transfer the remaining dirty pages to the > >> destination and start collecting the state of the devices. > >=20 > > Is there a reason to make this a separate step from the SYNC > > operation? >=20 > Hmm, apart from letting QEMU orchestrate the migration step by step, no. >=20 > We could merge the SYNC and the SAVE_EQ_PAGES in a single KVM operation.= =20 > I think that should be fine. I think that makes sense. SYNC is supposed to complete delivery of any in-flight interrupts, and to me writing to the queue page and marking it dirty as a result is a logical part of that. > However, it does not make sense to call this operation without the VM=20 > being stopped. I wonder how this can checked from KVM. May be we > can't. I don't think it matters. qemu is allowed to shoot itself in the foot. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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