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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 6D23AC432C3 for ; Sat, 23 Nov 2019 16:50:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4560E2070E for ; Sat, 23 Nov 2019 16:50:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RaK7RGaL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726961AbfKWQuW (ORCPT ); Sat, 23 Nov 2019 11:50:22 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:26249 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726836AbfKWQuW (ORCPT ); Sat, 23 Nov 2019 11:50:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574527820; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iQ1nYZicRuCsr2N4GxCFhhF1w/8zoaTyzM1kGYuOUrs=; b=RaK7RGaLv6d1oAkRsguEZ9uMYYkncoFGq88NFmY0+crPFFgCjAbJUNtjNczMg+Kz30rbRq mm0w1p2icQPH3Gz9stCC1YEptxOFGT1yIsP2n4srk2DzjPXcdwYOB1TO0pWezqWV18LyCW +bgKhnojPPT4MrP6knu2hMW4cByOw4A= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-321-yAB2hYbLN525BlRsfqfSPg-1; Sat, 23 Nov 2019 11:50:19 -0500 Received: by mail-qk1-f198.google.com with SMTP id o11so6580245qkk.7 for ; Sat, 23 Nov 2019 08:50:19 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=sHQia/lsWr35bKNwE4bTfDIwWlqfBFukr8BZYG19Bvg=; b=MehHzX+TV0Gni1NCJFe88V1I5hZHmf/v77FR6PShgbdFHAU4dViM4OkReJo0jYs5Nw pKlxYy/oIwM+dqHl5YVaMtwVMf5vFcQV+Zq+cwznxCkr87/Nj8RjTOrxJbImB3byCihX K1mcAlT0Ku67AJz6TInEnP7tRg54Qa6RrqWlsQ7Memd69giOThiCy4gGnXv5jDrZeq9C kX+zZJo/Et7yl5KparNS92zv/j6ogzpVMYtPOeps6x4r7niFlIXFduF3okkrYD4G91Gm OdvuUaRLCvewN+JeqvqKip2Fkdwnm8zKMQa14RCUgh88Dr6Fd80+xIlBimtGUQJT6Rhp 0CSw== X-Gm-Message-State: APjAAAXH5X8rC1EKQ9cwbNkA0QkXF8Szb23pAPSOz6GSmcMKE002JFhH Fa07rvq+GB/dh+4nGbafznRplyCef5IKAMEfor3yf5wOw0IPg1KUsHqNvdZYhduqyry9v/+HPcm MwRnvsQK5FyKrCCHA X-Received: by 2002:a05:6214:714:: with SMTP id b20mr19350112qvz.39.1574527818914; Sat, 23 Nov 2019 08:50:18 -0800 (PST) X-Google-Smtp-Source: APXvYqwQkY9bRii1J8sOZZLrXlXUoek5EdKj2DISUCJ7pbGOCucB5U5NnqaFttqpKqneVM87FnK6NQ== X-Received: by 2002:a05:6214:714:: with SMTP id b20mr19350084qvz.39.1574527818689; Sat, 23 Nov 2019 08:50:18 -0800 (PST) Received: from redhat.com (bzq-79-176-6-42.red.bezeqint.net. [79.176.6.42]) by smtp.gmail.com with ESMTPSA id j2sm609954qka.88.2019.11.23.08.50.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 23 Nov 2019 08:50:17 -0800 (PST) Date: Sat, 23 Nov 2019 11:50:11 -0500 From: "Michael S. Tsirkin" To: Jason Gunthorpe Cc: Alex Williamson , Jason Wang , Parav Pandit , Jeff Kirsher , davem@davemloft.net, gregkh@linuxfoundation.org, Dave Ertman , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, Kiran Patil , Tiwei Bie Subject: Re: [net-next v2 1/1] virtual-bus: Implementation of Virtual Bus Message-ID: <20191123114911-mutt-send-email-mst@kernel.org> References: <20191119191053-mutt-send-email-mst@kernel.org> <20191120014653.GR4991@ziepe.ca> <134058913.35624136.1574222360435.JavaMail.zimbra@redhat.com> <20191120133835.GC22515@ziepe.ca> <20191120102856.7e01e2e2@x1.home> <20191120181108.GJ22515@ziepe.ca> <20191120150732.2fffa141@x1.home> <20191121030357.GB16914@ziepe.ca> <20191120232320-mutt-send-email-mst@kernel.org> <20191121134438.GA7448@ziepe.ca> MIME-Version: 1.0 In-Reply-To: <20191121134438.GA7448@ziepe.ca> X-MC-Unique: yAB2hYbLN525BlRsfqfSPg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Nov 21, 2019 at 09:44:38AM -0400, Jason Gunthorpe wrote: > On Wed, Nov 20, 2019 at 11:24:03PM -0500, Michael S. Tsirkin wrote: > > On Wed, Nov 20, 2019 at 11:03:57PM -0400, Jason Gunthorpe wrote: > > > Frankly, when I look at what this virtio stuff is doing I see RDMA: > > > - Both have a secure BAR pages for mmaping to userspace (or VM) > > > - Both are prevented from interacting with the device at a register > > > level and must call to the kernel - ie creating resources is a > > > kernel call - for security. > > > - Both create command request/response rings in userspace controlled > > > memory and have HW DMA to read requests and DMA to generate respon= ses > > > - Both allow the work on the rings to DMA outside the ring to > > > addresses controlled by userspace. > > > - Both have to support a mixture of HW that uses on-device security > > > or IOMMU based security. > >=20 > > The main difference is userspace/drivers need to be portable with > > virtio. >=20 > rdma also has a stable/portable user space library API that is > portable to multiple operating systems. >=20 > What you don't like is that RDMA userspace has driver-specific > code. Ie the kernel interface is not fully hardware independent. >=20 > Jason Right. Not that I don't like it, it has some advantages too. But it's addressing a different need which a vendor specific userspace driver doesn't address. --=20 MST