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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 626FAC433EF for ; Tue, 5 Jul 2022 16:03:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231463AbiGEQD3 (ORCPT ); Tue, 5 Jul 2022 12:03:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230032AbiGEQDX (ORCPT ); Tue, 5 Jul 2022 12:03:23 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4803F100A for ; Tue, 5 Jul 2022 09:03:22 -0700 (PDT) Received: from arch-x1c3 (cpc92308-cmbg19-2-0-cust99.5-4.cable.virginm.net [82.24.248.100]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: evelikov) by madras.collabora.co.uk (Postfix) with ESMTPSA id EDBAE6601638; Tue, 5 Jul 2022 17:03:19 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1657037000; bh=PuRJwgghVrWRSi/gz8l232C34f7rDIf/ZjkluxP+eIg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EEjgCRzIRvo/SASMqeO8WsKm+7F5oUsdSCkNRG4IVKyViQojd/IVCpa3j+mgQwjFy +nVxTkIJN0x5pF2HDziGELT5nZnQMTa0tn4Kw1tGzc3Q5RsdPO6W3Hdbuf6NmGM2Zs G4M8sky9c1kPnwfzELGHUss/BFz/cn4Jx99+y/SuK7z5m7a6SNAtK/o1t+n/7Z3+Ah 2Jt55TVfcCFZZ9Ixn9FkQ/9gco+pQl6g+oppgXtjsv9jcgX/cD4BhlsBxWwCeucd3u MJmGTWvrVXSKZTWfICAFNzNn0nd5TzSE2WAK6H9n7LGJdOtgDeI9IQTWl1BhBxtEmp H601x76Bo6RJQ== Date: Tue, 5 Jul 2022 17:03:16 +0100 From: Emil Velikov To: Gerd Hoffmann Cc: Dmitry Osipenko , kernel@collabora.com, David Airlie , Thomas =?iso-8859-1?Q?Hellstr=F6m?= , Emil Velikov , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Gurchetan Singh , Thomas Zimmermann , Dmitry Osipenko , virtualization@lists.linux-foundation.org, Robin Murphy Subject: Re: [PATCH v7 7/9] drm/virtio: Improve DMA API usage for shmem BOs Message-ID: References: <20220630200726.1884320-1-dmitry.osipenko@collabora.com> <20220630200726.1884320-8-dmitry.osipenko@collabora.com> <20220705135323.emr4gdbcxoisdcxe@sirius.home.kraxel.org> <20220705154507.67ovlun4m26xzppn@sirius.home.kraxel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220705154507.67ovlun4m26xzppn@sirius.home.kraxel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/07/05, Gerd Hoffmann wrote: > Hi, > > > > Also note that pci is not the only virtio transport we have. > > > > The VirtIO indeed has other transports, but only PCI is really supported > > in case of the VirtIO-GPU in kernel and in Qemu/crosvm, AFAICT. Hence > > only the PCI transport was tested. > > qemu -M microvm \ > -global virtio-mmio.force-legacy=false \ > -device virtio-gpu-device > > Gives you a functional virtio-gpu device on virtio-mmio. > > aarch64 virt machines support both pci and mmio too. > s390x has virtio-gpu-ccw ... > As the last person who was there - the problem is indeed when using virtio on top of mmio. If that's no longer supported by the kernel then the hacky code-path can be dropped. Even in that case, I would suggest keeping it a separate commit. HTH Emil