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 0F3FBC4167B for ; Wed, 8 Nov 2023 17:20:32 +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 BC0873E589 for ; Wed, 8 Nov 2023 17:20:31 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 504DC986D3B for ; Wed, 8 Nov 2023 17:20:31 +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 C5CEA986CAB; Wed, 8 Nov 2023 17:20:30 +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 1FFDC986CA9 for ; Wed, 8 Nov 2023 17:20:08 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: IIy9oJJeNSuH0x4oJX8txg-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699463999; x=1700068799; 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=7DcTrvg0WdG0Lgdtl++mXYpUSEnqDLZll3TWp5NJc2Q=; b=gvrceRySk+i5rhg3KSZuxPCanh3ZS+fGGy4/hcAAav8ufymH3PgE1gUtaUPei6RCCR BNcCD2aWDkfLjhRl9Bk4Oi2CcMZ4ZSy95ZNDd1bGoQwdYTK6ulD4l5lCOaNTW1gKuCX+ izPG+gTMK8Db/mdkcV0Pz/iWk7AOvQkFPz3G7TmzTzKBorG21nPJ1iU4nSZnHoM1f88s CK3OVozeGdgAKYRmTZyfeUOWNvRiAUDRH8wS6AGChhXCzjWoCoEXDPkCE9mvzjjWdxLd dHG0T1H0PvFACCL/ti1p8FdGNcWPDQ+P9Wdlou4JM6qkV4uTQ1HYZ+isdpGzYDdb2Ole S48w== X-Gm-Message-State: AOJu0YxpVBBbFOY69Vykt4ZQ3t/d/8RE/R+G7jzBHq2h0n3Gq3fcOoCw +EJKVVy8/qL8SEwpVf+lvma9XEL9JbD8SQt52E9ayVKUVczZJW38NzGRToLQUVJaASXVcEhBvAf YXkiwQYcVxldGv25izR7Q/V/Fakod3v1XfA== X-Received: by 2002:a05:6512:230c:b0:507:cb61:2054 with SMTP id o12-20020a056512230c00b00507cb612054mr2288532lfu.49.1699463999661; Wed, 08 Nov 2023 09:19:59 -0800 (PST) X-Google-Smtp-Source: AGHT+IE4uT5L02f1QQpOxtWJ4VXbUFvAqjriFWRK8tEtIQDsZriRZjMdJPWBb/+w/DTDLbJKHgnvWw== X-Received: by 2002:a05:6512:230c:b0:507:cb61:2054 with SMTP id o12-20020a056512230c00b00507cb612054mr2288515lfu.49.1699463999333; Wed, 08 Nov 2023 09:19:59 -0800 (PST) Date: Wed, 8 Nov 2023 12:19:55 -0500 From: "Michael S. Tsirkin" To: "Zhu, Lingshan" Cc: Parav Pandit , "jasowang@redhat.com" , "eperezma@redhat.com" , "cohuck@redhat.com" , "stefanha@redhat.com" , "virtio-comment@lists.oasis-open.org" Message-ID: <20231108121916-mutt-send-email-mst@kernel.org> References: <445ff573-72c3-4fe4-9e07-e7fdd2dc5750@intel.com> <2615baa2-9450-4504-aa8a-e46fdbb332b8@intel.com> <20231107063139-mutt-send-email-mst@kernel.org> <033cad04-6840-420e-a320-051894eb484c@intel.com> MIME-Version: 1.0 In-Reply-To: <033cad04-6840-420e-a320-051894eb484c@intel.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [virtio-comment] Re: [PATCH V2 6/6] virtio-pci: implement dirty page tracking On Wed, Nov 08, 2023 at 05:30:02PM +0800, Zhu, Lingshan wrote: > > > On 11/7/2023 7:33 PM, Michael S. Tsirkin wrote: > > On Tue, Nov 07, 2023 at 05:52:41PM +0800, Zhu, Lingshan wrote: > > > > > > > > 2. the PCI FLR is clearing all the registers you exposed here. > > > > > > > see above > > > > > > > > 3. Endless expansion of config registers of dirty tracking is not > > > > > > > > scalable, as they > > > > > > > are not init time registers not following the Appendix B guidelines. > > > > > > > endless expansion?? It is a complete set of dirty page tracking, right???? > > > > > > > have you see this cap only controls? The device DMA writes the > > > > > > > bitmap, not by registers. > > > > > > Device dirty page tracking is start/stop command to be done by the > > > > > hypervisor. > > > > > > So when guest is resetting the device, it stopped the DMA initiated by the > > > > > hypervisor. > > > > > > This fundamentally breaks things. > > > > > Why? When device resets, do you want to keep tracking dirty pages???? > > > > Yes, when the device resets, before that event occurred, all the pages which were dirtied, must be migrated. > > > > And after reset also new page tracking to continue. > > > That depends on whether there is an interrupt for the dirty pages. > > > If there is an interrupt, then the guest owns the pages > > Not in the virtio model, guest owns the memory once buffer has been used. > Yes and even better, interrupt happens after buffers marked as used. But guest owns memory earlier and you can not change it after this point. This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: virtio-comment-subscribe@lists.oasis-open.org Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org List help: virtio-comment-help@lists.oasis-open.org List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/