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 Received: from ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5167FC77B75 for ; Tue, 16 May 2023 05:38:12 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 7455E23D67 for ; Tue, 16 May 2023 05:38:11 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 516BC9865B0 for ; Tue, 16 May 2023 05:38:11 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id 32FB3983E4A; Tue, 16 May 2023 05:38:11 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 1E01F986510 for ; Tue, 16 May 2023 05:38:11 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: KlBAAL1JMYy8lbY7nbcV0Q-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684215487; x=1686807487; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=J3L3sxiIv2iMIYjweg4bwNR0mcDkJJqub61egE6dp44=; b=dyisO+gaJMXxeiCqRkDFlNfnn+P1QCxeoSSecaNmWkdeLj7PEqXrHo49e0M+weUVQ+ 7sHFs5XFwxHFJVMM9mhBLrEBe7PRkyj68c2ENCdMowen/Gz+A+yRFVbkMAuHnPheLCnt KaiGwa/OI2CdhdehKypc/sQ/CaJ1j9DnEBJf93BgELdDUKYQubvrV4I7qQgQa5N/r7Qr yEx1QFDo7/4NVNUXmh58JoTmouu+UkuGSKBFBs3bQJz5zVOC4UbuTB84CdcnbgGzJVxW 2cjEjV9UnPJHn0TZltI8lcaN61I+Z0qW9Dw5jIV6LBetgzTI70wKqD8sphcA43P2c5m7 RQlA== X-Gm-Message-State: AC+VfDws5nOYxGb5SAnx9aV6NA6+GzIZYXuyoJlqFSgup/6HWX7Yi1Fk XjLEpqvJsZVQJjg/LgiyuMoDb5QW74Ofn9tu8UNlMAJ7nxE+ANvHmmkoKXJGaYYRDq2hBXN1CAF uvBojsH7w6O/+ZBzo9KXUDXGpYAk4 X-Received: by 2002:a1c:f402:0:b0:3f0:44d1:3ba5 with SMTP id z2-20020a1cf402000000b003f044d13ba5mr25235320wma.5.1684215487712; Mon, 15 May 2023 22:38:07 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6uZdsPQOyXLLWdjQ6em8yx4Rm7wrXu4OlLdsQ2E8l4QKJ+biJ8NVOH+t9gjcgn2z5wo8pHUA== X-Received: by 2002:a1c:f402:0:b0:3f0:44d1:3ba5 with SMTP id z2-20020a1cf402000000b003f044d13ba5mr25235308wma.5.1684215487423; Mon, 15 May 2023 22:38:07 -0700 (PDT) Date: Tue, 16 May 2023 01:38:03 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: Parav Pandit , "virtio-dev@lists.oasis-open.org" , "cohuck@redhat.com" , "david.edmondson@oracle.com" , "sburla@marvell.com" , Yishai Hadas , Maor Gottlieb , "virtio-comment@lists.oasis-open.org" , Shahaf Shuler Message-ID: <20230516013721-mutt-send-email-mst@kernel.org> References: <893b6ec0-a74f-69b7-95a3-988f0f9382a8@redhat.com> <20230515133719-mutt-send-email-mst@kernel.org> <20230515135513-mutt-send-email-mst@kernel.org> <20230515140052-mutt-send-email-mst@kernel.org> <78ade48a-6f5d-8a2d-1524-44340f0154ce@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Subject: [virtio-dev] Re: [PATCH v2 0/2] transport-pci: Introduce legacy registers access using AQ On Tue, May 16, 2023 at 11:43:09AM +0800, Jason Wang wrote: > On Tue, May 16, 2023 at 11:37 AM Jason Wang wrote: > > > > > > 在 2023/5/16 02:01, Michael S. Tsirkin 写道: > > > On Mon, May 15, 2023 at 06:00:02PM +0000, Parav Pandit wrote: > > >>> From: Michael S. Tsirkin > > >>> Sent: Monday, May 15, 2023 1:56 PM > > >>> > > >>> On Mon, May 15, 2023 at 05:51:05PM +0000, Parav Pandit wrote: > > >>>>> From: Michael S. Tsirkin > > >>>>> Sent: Monday, May 15, 2023 1:45 PM > > >>>>> > > >>>>> On Mon, May 15, 2023 at 03:49:44PM +0000, Parav Pandit wrote: > > >>>>>> All legacy interface via AQ. > > >>>>>> All modern interface access via PCI or its own transport between > > >>>>>> driver and > > >>>>> device. > > >>>>> > > >>>>> I am wondering however about the hypervisor notifications. > > >>>>> Generally these are the most problematic aspect here I feel. For > > >>>>> example, how does it interact with VIRTIO_F_NOTIF_CONFIG_DATA? And > > >>>>> generally, having both guest and host be allowed to access device's BAR > > >>> seems problematic. > > >>>>> Can we reserve a PF BAR region for these things or is that too expensive? > > >>>> VIRTIO_F_NOTIF_CONFIG_DATA is not present for the legacy. > > >>> it is not but it just might be required, or it won't be there. > > >>> > > >> How can it be required if it not part of it? > > >> I likely didn't follow your question/comment, can you please explain. > > > VIRTIO_F_NOTIF_CONFIG_DATA is there presumably for a reason. > > > > > >>>> For modern device, guest driver will access the device own BAR directly with > > >>> its own config_data anyway. > > >>>> Should we reserve a region in the PF BAR for SF/SIOV device?, should device > > >>> report which BAR/area to use for the given SF/SIOV device? > > >>>> May be yes, those are different discussions with tradeoff to consider during > > >>> SIOV discussions. It is not related to VFs. > > >>> > > >>> For SIOV it's a given. But we can do this for SRIOV: reserve a PF region per VF. > > >> Each VF has its own BAR area for driver notifications. > > > But it is passed through to guest presumably. > > > > > > Probably not in the case of VIRTIO_F_NOTIF_CONFIG_DATA. Did you see any > > problem if we do mediation here except for some performance penalty? > > Ok, rethink of this, when using legacy, VIRTIO_F_NOTIF_CONFIG_DATA > should be assumed to be not negotiated. So I think I agree with Parav, > it should not be a problem. > > Or do you mean for the devices that have some mandated features? > > Thanks Exactly. VIRTIO_F_NOTIF_CONFIG_DATA if there is likely to be required for device to work as opposed to being an optimization. > > > > Thanks > > > > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org