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 752E11A2541 for ; Thu, 17 Jul 2025 13:25:24 +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=1752758726; cv=none; b=o7fPugi/9gKUqg/c3uHWgbJx9gVdcdqta/UaoiPeeSVSxKNIZ2XRmX6C9cOm0P5CbuhUhZfHGeAe81GMmysXqO2Kh5Y9EsUikPhT/ypOku9kprpddKV8hIMqrqqN9gkeNt7Gxw5AIED9aqKU+4FE0kidL5sO6xo19UMRwEIkwLI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752758726; c=relaxed/simple; bh=z2z9OenFaQFo8Yw+Ya8ieWGGBBMxpYWICf7q48CcMh0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=t4jcR1TlShzNMa4flwtZ5D1zQi9HhsYDpvSq3X3RqKidsfOTTyD7vczLQTvzns2472Cow5D3Cfw2+XzSSIETODm26xmS82Zwo9a0BRjyt1t/G5M134XKPdMkJhF+B3W5Ges/Xy6XxZwP3O35qDup1HW6AvxLgrC+hM47vX0ZBmI= 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=dAkCEFW7; 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="dAkCEFW7" 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=R9eaq33RkhcFSbSUjoHcP2qsAeTezdphMnOwT07Jogs=; b=dAkCEFW7R9Nx+/WaIHraywab9Q AgWaJU7MNoGm7yepEf62oCavTkja01r1Lwye5NdPC13NC6DfejmMfsENaDDUkCjtQLJFjDLyfOVyK FXHosrN10mpBmHKutwFTfWenl4l6+OOVozs7wpU39uiX7UOQ6ujvAs2dkEzo3G/dd2LBLK8URp/7N lLQtT5s900dnX6lp+24pkrs10Yh1MOytQYD7HmYI+brjpJBf0LpFtW6rt3e1OhGaqRggSoPB/hpz/ 8ItqkV00yiE3gUrx0FH4FQJDCiPbK/AmvTKy9PxXQg6BP8pDYBaJbWe0zEtrVyI+jvJsDoVeJ6fXK oUi2aCgg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1ucObz-0000000AFdC-3BT9; Thu, 17 Jul 2025 13:25:23 +0000 Date: Thu, 17 Jul 2025 06:25:23 -0700 From: Christoph Hellwig To: Jason Wang Cc: mst@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, virtualization@lists.linux.dev, hch@infradead.org Subject: Re: [PATCH V2 9/9] vduse: switch to use virtio map API instead of DMA API Message-ID: References: <20250717080237.6518-1-jasowang@redhat.com> <20250717080237.6518-10-jasowang@redhat.com> 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: <20250717080237.6518-10-jasowang@redhat.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Jul 17, 2025 at 04:02:37PM +0800, Jason Wang wrote: > Lacking the support of device specific mapping supported in virtio, > VDUSE must trick the DMA API in order to make virtio-vdpa transport > work. This is done by advertising vDPA device as dma device with a > VDUSE specific dma_ops even if it doesn't do DMA at all. > > This will be fixed by this patch. Thanks to the new mapping operations > support by virtio and vDPA. VDUSE can simply switch to advertise its > specific mappings operations to virtio via virtio-vdpa then DMA API is > not needed for VDUSE any more. This can now drop the depends on HAS_DMA and ARCH_HAS_DMA_OPS for VDPA_USER.