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 DACF2C77B75 for ; Mon, 15 May 2023 07:31:00 +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 0D64411B692 for ; Mon, 15 May 2023 07:31:00 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 02904986514 for ; Mon, 15 May 2023 07:31:00 +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 E92A398636A; Mon, 15 May 2023 07:30:59 +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 D4D47986430 for ; Mon, 15 May 2023 07:30:59 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: 4cw-6P2ZMv6kXBRMRptsgA-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684135855; x=1686727855; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=74J+9nUvx7fAMDOYx+zxq20d3gkbLbZP3fe6J2gYXkU=; b=M2ArLPAkODAiw5E7eF57OorVQpUrETNpAux9xaIcNQlP38Aztqsx4QU9YKnejrePUe jDJRDcgTsMOHiWGKCh4ohftuWh4/ipz/jeGBFtlZGVeOkHXi2GHsoBOVowKFP1/xRqA4 Pbpem0wPMtZKBcDTzKDkAl4g22buQovy7pTJiyR0TvpI8GsHIWDYxX3sRV3DS+ux1Gum Mns24G9pAnWH1xO3c9A/gT5Qp8mkOWdCEaV29SacvB6vLEXoX+y1rj9fFG7kdE2UN7iy sDcNh7z+RVcLETkxW5Es6BL+SFJeRdA0OF6EWLXLSugzRGTKvScX1h0l08GXe06R1NG7 /zcQ== X-Gm-Message-State: AC+VfDwGFpv2DDBHIDc6/Nt8lAu8ErTDGRiKqDipCTG3d+7QzKwiUs1l f+n0LUBf3EvL2izTZXPt45PoPJui4SjBEhOCuDJn9nPzc1ik2mEQAGz7kK+5eQNlEXVx8HAWv4O 3mbdMMrE6X6Hh9JEO5TrUBuFSQ01P X-Received: by 2002:a05:6a21:32a8:b0:100:60f3:2975 with SMTP id yt40-20020a056a2132a800b0010060f32975mr33469234pzb.4.1684135855183; Mon, 15 May 2023 00:30:55 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4oDfoeyk25oQkcCj5/EJEDiLL6CU4x25zeQtEPMdwv6b7fwqmpwbu4D2FMLlhbpUYT0B1RAg== X-Received: by 2002:a05:6a21:32a8:b0:100:60f3:2975 with SMTP id yt40-20020a056a2132a800b0010060f32975mr33469213pzb.4.1684135854895; Mon, 15 May 2023 00:30:54 -0700 (PDT) Message-ID: <0f75a142-71e9-676a-11ae-a54e6dbb472d@redhat.com> Date: Mon, 15 May 2023 15:30:47 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 To: Parav Pandit , "Michael S. Tsirkin" Cc: "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 References: <20230506000135.628899-1-parav@nvidia.com> <20230507093959-mutt-send-email-mst@kernel.org> <20230510014534-mutt-send-email-mst@kernel.org> <20230510033812-mutt-send-email-mst@kernel.org> <20230511085205-mutt-send-email-mst@kernel.org> From: Jason Wang In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: [virtio-dev] Re: [PATCH v2 0/2] transport-pci: Introduce legacy registers access using AQ 在 2023/5/11 21:02, Parav Pandit 写道: > >> From: Michael S. Tsirkin >> Sent: Thursday, May 11, 2023 8:55 AM >>> 1) device features >>> 2) driver features >>> 3) queue address >>> 4) queue size >>> 5) queue select >>> 6) queue notify >>> 7) device status >>> 8) ISR status >>> 9) config msix >>> 10) queue msix >>> 11) device configuration space >>> > #9 may not even go to the group owner device. It the config_msix_vector register so I don't understand why it can't work but can work with your proposal. > What do we gain from bisecting it? 1) No need to deal with the offset in the hardware 2) transport independent 3) avoid duplication with the (legacy support of) transport virtqueue > Every new additional needs involvement of the hypervisor as Michael noted below on "effort" point. I'm not sure I get your point. If additional effort is not wanted, we need a full PCI over adminq, that's what I suggested, then we don't need any extension for any new features probably. If we choose to invent dedicated adminq commands: For legacy, we don't need any new additional effort since the above 11 maps to the legacy virtio-pci facilities. For modern, if the feature is something related to the transport, we need new transport interface for sure. > > The register offset and read/write is far simpler interface for hypervisor. If this is true, why not go full PCI over adminq? Hypervisor in this case even don't need to deal with config space. > > Not to do cross register access is what we need to define in the spec for 1.x or future things. You can't assume the hypervisor behaviors, so the device or at least the spec should be ready for that. Thanks > >>> It focuses on the facilities instead of transport specific details >>> like registers (we don't even need legacy registers in this case), I >>> gives more deterministic behavior so we don't need to care about the >>> cross registers read/write. >> This needs thought, it is definitely more work. Effort that could be maybe spent >> on new features. What is the motivation here? supporting legacy mmio guests? --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org