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 smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 49AEDEB64DA for ; Thu, 20 Jul 2023 06:55:29 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id B813E4023F; Thu, 20 Jul 2023 06:55:28 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org B813E4023F Authentication-Results: smtp2.osuosl.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=sKkUTSTA X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EGL4YfyGoCI6; Thu, 20 Jul 2023 06:55:26 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp2.osuosl.org (Postfix) with ESMTPS id B454740198; Thu, 20 Jul 2023 06:55:25 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org B454740198 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 74576C0071; Thu, 20 Jul 2023 06:55:25 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id CBFC7C0032 for ; Thu, 20 Jul 2023 06:55:23 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 92CCD4023F for ; Thu, 20 Jul 2023 06:55:23 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 92CCD4023F X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cQ5d-ywt59Pl for ; Thu, 20 Jul 2023 06:55:19 +0000 (UTC) X-Greylist: delayed 1986 seconds by postgrey-1.37 at util1.osuosl.org; Thu, 20 Jul 2023 06:55:19 UTC DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 2989540198 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by smtp2.osuosl.org (Postfix) with ESMTPS id 2989540198 for ; Thu, 20 Jul 2023 06:55:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=kMyO5VD0QAGAGdxVmS5onT7pkpxirlZJoxTfWvPS+OI=; b=sKkUTSTAGrySRXrA7yJnSEeKU7 pwTIPGGAM1fhU3lfi24JND0R05d6AoG9FkgOvASImWO3PiCLUKCsYdeRst/q3uzkblGx7dfPvF8GG mxtrpUrzJ9Hqxvp2KVT38+vOXonST6DJ+/o58XnKEDq4UHwfGK9XsHL9GB3HryJdFzxtVwjzy9Q6W uh5Fyu96H8RIuNcwpRN1yWf6ywBSNpTC26cezL6zyHH2/G6Ok12ySrRbe2AaXFxgc88i+S3X8/yCx E8lq0exbezp9I8NCl4nGEOBWTMGOFqtBTKAjLJeYwbFCbBlHbD76rCXYZJt8GqDkGg/9Zr1Zy4Ovp TFH1a/Xg==; Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1qMN39-009vKi-0L; Thu, 20 Jul 2023 06:22:07 +0000 Date: Wed, 19 Jul 2023 23:22:07 -0700 From: Christoph Hellwig To: "Michael S. Tsirkin" Subject: Re: [PATCH vhost v11 03/10] virtio_ring: introduce virtqueue_set_premapped() Message-ID: References: <20230710034237.12391-1-xuanzhuo@linux.alibaba.com> <20230710034237.12391-4-xuanzhuo@linux.alibaba.com> <20230713104542-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230713104542-mutt-send-email-mst@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Cc: Xuan Zhuo , Jesper Dangaard Brouer , Daniel Borkmann , netdev@vger.kernel.org, John Fastabend , Alexei Starovoitov , virtualization@lists.linux-foundation.org, Christoph Hellwig , Eric Dumazet , Jakub Kicinski , bpf@vger.kernel.org, Paolo Abeni , "David S. Miller" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Thu, Jul 13, 2023 at 10:47:23AM -0400, Michael S. Tsirkin wrote: > There are a gazillion virtio drivers and most of them just use the > virtio API, without bothering with these micro-optimizations. virtio > already tracks addresses so mapping/unmapping them for DMA is easier > done in the core. It's only networking and only with XDP where the > difference becomes measureable. Yes, but now you two differing code paths (which then branch into another two with the fake DMA mappings). I'm really worried about the madness that follows like the USB dma mapping code that is a constant soure of trouble. _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization