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 81F3524167D; Thu, 3 Apr 2025 07:44:48 +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=1743666289; cv=none; b=tdEwqGAfeFirrcHA+VjeREqvX0HgAMJyEB3YmwAqE31bII62GlUm3DH9CJpP/okvXfeShdf4maIkmRPHcWstLiAAmCll2jvUH8SlDKTlF2Mg5oOXw7kSYreI1UR6FghYWr+lZcXbGKxbJ2XhaxdPl0s3JnJcprjkMalGwu2SeTQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743666289; c=relaxed/simple; bh=nBIcltQZNSJSeJcVlDAWs1DczIo6DIsS7I5l0/GkUm4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XtlLz7xQzP4BRYCPWi6mae7IaJzgDmUHKgMaIkSBng+z4+hG9IqnIfHq35hGtJuH8CDogSTNfMpcyEz33wOiasTPshg8B8NvthHSQZeO/K8bs7oQflyVbLVEow6lJTTYmuLX9QTlAQrIiwOzfEhsL0sJwmknpmclePZhrgQZ1ig= 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=Qv6zWAeU; 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="Qv6zWAeU" 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=nBIcltQZNSJSeJcVlDAWs1DczIo6DIsS7I5l0/GkUm4=; b=Qv6zWAeUIY0Vtbpp83QhnfISu2 4ghv4UddYKGczy7Mr1729cLMlaUhaTjDnb5EGcrNcEtimPBG3ICMZgZp2s1SScGtFQF005ye6eAxY RHCvn+NvVR9KopeGlBzqvSj6zRpXkU13LiKhIElH2Ii9+uayrnIp92TM8HuISssy8FX+oH8EWTD4g J7jEEo97VW4H3zG8IK0Iwh7/AKwl1ry/SgjmluKTT5DpBx3YJCv8gjweD/USYFIOKzRr56sMi2ZqH 3JfeSL+XvFCl2+09tw+5Fsolc/hShbI+p03BI5IntCqI1S2PPDoVyhN6v45fqYiV9uiRv9H88HovJ kxTPdpCQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.1 #2 (Red Hat Linux)) id 1u0FFn-00000008A0d-40Nf; Thu, 03 Apr 2025 07:44:47 +0000 Date: Thu, 3 Apr 2025 00:44:47 -0700 From: Christoph Hellwig To: "Michael S. Tsirkin" Cc: Christoph Hellwig , David Woodhouse , virtio-comment@lists.linux.dev, Claire Chang , linux-devicetree , Rob Herring , =?iso-8859-1?Q?J=F6rg?= Roedel , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, graf@amazon.de Subject: Re: [RFC PATCH 1/3] content: Add VIRTIO_F_SWIOTLB to negotiate use of SWIOTLB bounce buffers Message-ID: References: <20250402111901-mutt-send-email-mst@kernel.org> <6b3b047f1650d91abe5e523dd7f862c6f7ee6611.camel@infradead.org> <20250402114757-mutt-send-email-mst@kernel.org> <965ccf2f972c5d5f1f4edacb227f03171f20e887.camel@infradead.org> <20250402124131-mutt-send-email-mst@kernel.org> <06465bcf4422d088df2a0ce9cdb09767dac83118.camel@infradead.org> <20250403034143-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250403034143-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 On Thu, Apr 03, 2025 at 03:43:31AM -0400, Michael S. Tsirkin wrote: > Hm. This is what this proposal does, indeed. Can be changed though - > since all accesses are now within the SWIOTLB, they can be treated > as offsets instead. Yes, marking them as offsets into the BAR (including potentially picking a specific BAR or region if there is more than one) is the right interface and implemented by various hardware that way.