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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 056BAC8300A for ; Thu, 30 Apr 2020 10:08:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D50BD2186A for ; Thu, 30 Apr 2020 10:08:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588241309; bh=xa6SpmSmz9EAdtVLWr+Oo3a8W/zi6Yh4mLHT8M/Bb5g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=N/7v5q8PkfGwmEg2lZLM0jdSrNUmM3bdzVvhyk8hSxMwoJ27gJ/dRAvHf7vIFjPoz jVVhR35up/4XQg34LheRMwH4+C1OpzUQTzsLF1Vi9le6jkGzIQF7bZLvc/5rcg+Nhw ZChcZ3pm5iIHIyse31STMChlaBXR/Tm2wUmr3png= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726817AbgD3KI2 (ORCPT ); Thu, 30 Apr 2020 06:08:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:44272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbgD3KI2 (ORCPT ); Thu, 30 Apr 2020 06:08:28 -0400 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98A012173E; Thu, 30 Apr 2020 10:08:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588241308; bh=xa6SpmSmz9EAdtVLWr+Oo3a8W/zi6Yh4mLHT8M/Bb5g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GCUHU4XQOC1NYyjmFXVXCCbulAEM7AZSTxyQ7+5I2SwHz/G+uEMnzpoE4im98LLc8 wgr0/Gjnbc+UtBMh7+Fs0Cnj/od/q3LJ/UT4MmYDHK3a5/o+rhH2n1z5vbDrO/Is7j sIS1+lyZbST/U8limbFBI5yeJZYFzMq+yVAkgwWM= Date: Thu, 30 Apr 2020 11:08:22 +0100 From: Will Deacon To: Srivatsa Vaddagiri Cc: konrad.wilk@oracle.com, mst@redhat.com, jasowang@redhat.com, jan.kiszka@siemens.com, stefano.stabellini@xilinx.com, iommu@lists.linux-foundation.org, virtualization@lists.linux-foundation.org, virtio-dev@lists.oasis-open.org, tsoni@codeaurora.org, pratikp@codeaurora.org, christoffer.dall@arm.com, alex.bennee@linaro.org, linux-kernel@vger.kernel.org Subject: Re: [RFC/PATCH 0/1] virtio_mmio: hypervisor specific interfaces for MMIO Message-ID: <20200430100821.GC19932@willie-the-truck> References: <1588240976-10213-1-git-send-email-vatsa@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1588240976-10213-1-git-send-email-vatsa@codeaurora.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 30, 2020 at 03:32:55PM +0530, Srivatsa Vaddagiri wrote: > The Type-1 hypervisor we are dealing with does not allow for MMIO transport. > [1] summarizes some of the problems we have in making virtio work on such > hypervisors. This patch proposes a solution for transport problem viz how we can > do config space IO on such a hypervisor. Hypervisor specific methods > introduced allows for seamless IO of config space. Seamless huh? You'd hope that might obviate the need for extra patches... > This patch is meant to seek comments. If its considered to be in right > direction, will work on making it more complete and send the next version! What's stopping you from implementing the trapping support in the hypervisor? Unlike the other patches you sent out, where the guest memory is not accessible to the host, there doesn't seem to be any advantage to not having trapping support, or am I missing something here? Will