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 5B350C4167B for ; Mon, 27 Nov 2023 11:47:33 +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 A6BE4EEA0F for ; Mon, 27 Nov 2023 11:47:32 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 7E43A9863B5 for ; Mon, 27 Nov 2023 11:47:32 +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 64CA698638E; Mon, 27 Nov 2023 11:47:32 +0000 (UTC) Mailing-List: contact virtio-comment-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 548D6986394 for ; Mon, 27 Nov 2023 11:47:32 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: AvUR_4AANwytX2PDceJqhA-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701085649; x=1701690449; h=in-reply-to: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=ihNdUI6nDeao0EfKyg8yfuSAn7XKctRQvxfbVUTHtjc=; b=dyC0GU2hp2ROcRrainFEYDKOAHM7XV0W+ZHFlM8GhTk2IVY0hEryuu89hBTb8t7GfC Trzpm845jCgPII7o0b3RgO9z2gZvSCwaEPvGQg91Xmat3fhDTCGiJ9On2xRT6Yg+iGMJ 0W2JZ3m6KPAPh7clN028ixxyo5h/o2HrCC28DQo7wEveTeVfU4YSrvQToz2Pa7eQ+CNH 3jf+6reHE3RhuVu8zPF182+T020A9MD9VFrVP2oIoWMgqXSWss9vKDQllTzN+MLv68v4 tXrrmHJW6jAbHrBzg912ESNqG/kOv06X1IXahHMVKNAPvXQkcLWqeJW31dM5itULXlrj eHBQ== X-Gm-Message-State: AOJu0YzWwZhGzzxFuNhE3cmSf2vZ9cUrT91SHnHq4VsNLJ8wK5jmwxnu /W0WapNylstV+lD0TnOshdPirXQAiToYl9gJ7E123ifGECxEOsve2Tr3uWn90eeL/364TjEr3Zx Yaf2Kmslm0hfWNH6vz3dSV7qIuivhDptgSg== X-Received: by 2002:a05:6402:1a4b:b0:548:5671:b819 with SMTP id bf11-20020a0564021a4b00b005485671b819mr8221407edb.30.1701085649072; Mon, 27 Nov 2023 03:47:29 -0800 (PST) X-Google-Smtp-Source: AGHT+IHUKDtv4FMaEhU+k/kgzfrrDRNXYB+DMzmDkuinqFaTN+61C5Mu4hXfKDf4zYaNxj9ob0n8lA== X-Received: by 2002:a05:6402:1a4b:b0:548:5671:b819 with SMTP id bf11-20020a0564021a4b00b005485671b819mr8221384edb.30.1701085648714; Mon, 27 Nov 2023 03:47:28 -0800 (PST) Date: Mon, 27 Nov 2023 06:47:23 -0500 From: "Michael S. Tsirkin" To: Parav Pandit Cc: Jason Wang , "virtio-comment@lists.oasis-open.org" , "cohuck@redhat.com" , "sburla@marvell.com" , Shahaf Shuler , "si-wei.liu@oracle.com" , "xuanzhuo@linux.alibaba.com" , Heng Qi Message-ID: <20231127064138-mutt-send-email-mst@kernel.org> References: <20231124002357-mutt-send-email-mst@kernel.org> <20231124011125-mutt-send-email-mst@kernel.org> <20231124062907-mutt-send-email-mst@kernel.org> <20231127062256-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: Re: [virtio-comment] Re: [PATCH v6 2/5] virtio-net: Add flow filter capabilities read commands On Mon, Nov 27, 2023 at 11:40:25AM +0000, Parav Pandit wrote: > > > From: Michael S. Tsirkin > > Sent: Monday, November 27, 2023 4:58 PM > > > > On Mon, Nov 27, 2023 at 10:19:49AM +0000, Parav Pandit wrote: > > > > > > > From: Michael S. Tsirkin > > > > Sent: Friday, November 24, 2023 5:04 PM > > > > > > > > On Fri, Nov 24, 2023 at 06:31:03AM +0000, Parav Pandit wrote: > > > > > > > > > > > From: Michael S. Tsirkin > > > > > > Sent: Friday, November 24, 2023 11:48 AM > > > > > > > > > > > > On Fri, Nov 24, 2023 at 05:40:26AM +0000, Parav Pandit wrote: > > > > > > > > we > > > > > > > > strongly suggest that *drivers* support both old and new > > > > > > > > mechanism, and then *devices* will only implement what's > > required. > > > > > > > There are other examples in the same document that makes > > > > > > > things worst > > > > > > with old and new. > > > > > > > > > > > > > > Also there is literally no way to enforce that driver supports > > > > > > > both and new. It is just sounds like an excuse to force > > > > > > > infinite config space. > > > > > > > > > > > > There is a very simple method though. We allow devices to > > > > > > expose a subset of features when DMA is not used. So drivers > > > > > > that want maximum features will always opt for DMA. We can also > > > > > > strongly recommend that all drivers support DMA if available. > > > > > Yeah, don't see how this is elegant at all with all mixed bits. > > > > > > > > It's elegant because simple low end devices can cheaply implement > > > > MMIO and not worry about DMA. > > > > > > > It is not of much help in this case because any low end cheap device which > > want to support flow filter commands need to have CVQ anyway. > > > And hence reusing the same CVQ is more elegant that already does the DMA. > > > > > > So CVQ is fulfilling all the below needs. > > > 1. Single interface for the get/set config flow filters 2. DMA the > > > data 3. Not have any partial issues > > > > I don't know what these are. > I mean partial writes for fields. We don't allow these and in any case, writeble fields are best avoided. > > > > > 4. provides consistent structures that provisioning side will be able > > > to use > > > > Problem for provisioning is extra definitions will be needed, in a device specific > > way. > In vdpa tool and other OS tools of iproute2 developed, setting and getting those device specific values are useful. > It is ok. It does not become ok just by saying so. You are taking a single RO value and instead of it having an address there are now 2 other ways to address it. And you fail to see the problem and the pain you are inflicting on software developers. Just stick with an address if you can. > > > > > > > Nor do I see any enforcement, single method via cvq still holds strong. > > > > > > > > You don't need to enforce things, if people want to put a lot of RAM > > > > on device and put it in a register let them. > > > > > > > Not enforced. It uses the CVQ for flow group and flow filter life cycles and for > > the sharing this config as well. > > > Also aligns with stats that rest also agreed on. > > > > I am talking about your attempt to generally say "no more config fields > > everything must be in CVQ". > Config fields for initialization time is fine as the spec allows it today. > Things which can differ, it is ok to use cvq interface. I don't know what does "Things that can differ" means. Generally device caps are perfect for config space. Accessed at init time only, RO. > > I think it's wrong definitiely for non network > > devices must sometimes for network too and generally we need a solution for > > config over DMA. This specific thing - whether it fits in CVQ is a separate > > discussion. > > > I explained it before, that 6 out of 19 devices has cvq which are complex enough doing things over cvq. > These are non-network devices already. > > If one of those remaining device becomes complex, it is likely it will need a cvq to suffice for the dma interface and it can just do with depth = 1. Using generic caps and not net specific ones is a good idea. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > The method proposed here is elegant and clearly promote one > > > > > > > way to do > > > > > > things for driver and device with predictability. > > > > > > > > > > > > > > > > > > > I don't see it as elegant at all. What is elegant is *a single > > > > > > tag* that describes each property of the device. And this single > > > > > > tag should be > > > > good for everything: > > > > > > driver, provisioning, migration. And config space offset serves as such. > > > > > The single tag is the set of structures. > > > > > > > > I have no idea how this will work. If migration format i started > > > > reviewing is anything to go by then there will be a huge elaborate > > > > structure nothing single or simple. By comparison there's already a > > > > proposal how provisioning can work by supplying config space. > > > > it is just a clean model to grasp. > > > > > > > The provisioning model is simple is to supply all the configuration. > > > To draw parallels to some sw side, > > > > > > There is per functionality socket option to set things, instead of one giant > > structure. > > > There is per functionality ethtool option/cmd instead of Set ALL/get ALL > > enforcement. > > > > I'm not sure how much of a parallel one can draw. > > Do not see a lot of similarity. > For lot of configuration they are similar that happens at slow pace. > > > Devices commonly use register map. Everyone understands this paradigm. > > > For initialization early device setup time, yes. > > > > > I am not altogether happy with the way you are making migration generate > > duplicate definitions for lots of things we already have definitions for. > > Having a 3rd one for provisioning? Gimme a break. > > For migration, we are not duplicating. Some structures are not well defined, it has some duplication. And fyi it's already making people unhappy. > But large part seems be able to utilized pre-defined structs. > And here for flow filter also same structs will be used. So if there's a 64 bit bitmap in config space, then provisioning command which already gets config space can just use its offset. Simpler, better. > > > > > > > > > Provisioning access them via owner device. > > > > > Member driver access them via CVQ or 1.2 legacy config space. > > > > This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. 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