From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 62C402D29C8; Thu, 3 Jul 2025 08:57:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751533030; cv=none; b=l53SyF1ULEbyaLOF0qEm3ODNaL3dNT7ZAtGoapiWPWn7EkXxMFPOILidAkASf7fOTonlqaGF4tEnQDA1WznIF0ODFvgvs4ViJ60rbXNqX1Yr4FdCkiLjy/24xmh5nMkUu4HaM+GeWaBnXg/V+irCC6wUFtyQniBDgsNH9hyR11c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751533030; c=relaxed/simple; bh=NFW2YyTqEtJaZEFW122fYjnxT1eH+RBQ4tejPPFMRCo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=R2QhSo/hhX/2msagvFZaCeM7FHWqznVef/worDkW+TjFoB4jf/sp5iAccsbzxyGLCA//JHgTPEkb+surAuZl+c6MuVnZpV1GtHhebmTn+TSJi2pjMdRlIl9aQB9WIQNTVWzmZdmeMVhc33Ex7cts56LLOZ/FQ5hoW9livwTV6pg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=mBrdP+dT; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mBrdP+dT" 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=7v+FVph2p3AjKUXXMP962eD76NtSca8p122IP5PfJck=; b=mBrdP+dTWCx2IeD12Mcjc459U7 StfEKWNoxulXdMYk5WiKT5+w1eKkPakUmCOz6ef/r/TTPSPeCbaan+lpZv6L8rD4y5Esz+1LdDfhC ocgQo/0dF+d7PCZC+PbbGiuiCOB9hmOz90fnW6eZUr6Fwnf+Uw0yrXPt3hGq6AsDyN9NOjMlNAVOk gAs/NiZ7QrQfDCKl2/3oDSRFW4zxx7Q+o+zLTAcGbrSxcIMfinYM6wFn3wCioRIQzc7GqPmbxycdM D5dq/e/VaLMiYUa6RUr9veQIwIeQXu8vQymBGLzH6YSB8lbG29oV6WxPvRxt5QdrDn7Ir7i9ikRXZ Kxz5ROqw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uXFkh-0000000AkgY-3XwQ; Thu, 03 Jul 2025 08:57:07 +0000 Date: Thu, 3 Jul 2025 01:57:07 -0700 From: Christoph Hellwig To: Jason Wang Cc: "Michael S. Tsirkin" , xuanzhuo@linux.alibaba.com, eperezma@redhat.com, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, hch@infradead.org, xieyongji@bytedance.com Subject: Re: [PATCH 0/9] Refine virtio mapping API Message-ID: References: <20250701011401.74851-1-jasowang@redhat.com> <20250701030150-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Jul 01, 2025 at 04:00:31PM +0800, Jason Wang wrote: > Actually not, it doesn't change how things work for the device that > does DMA already like: > > If device has its specific mapping ops > go for device specific mapping ops > else > go for DMA API > > VDUSE is the only user now, and extra indirection has been used for > VDUSE even without this series (via abusing DMA API). This series > switch from: > > virtio core -> DMA API -> VDUSE DMA API -> iova domain ops > > to > > virtio core -> virtio map ops -> VDUSE map ops -> iova domain ops And that's exaxctly how it should be done. Thanks for doing the work! I'll go through if I find some nitpicks, but the concept is the only right one here.