Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 10 Mar 2020 19:47:41 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     David Rientjes <rientjes@google.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "Singh, Brijesh" <brijesh.singh@amd.com>,
        "Grimm, Jon" <jon.grimm@amd.com>, Joerg Roedel <joro@8bytes.org>,
        baekhw@google.com,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>
Subject: Re: [rfc 5/6] dma-direct: atomic allocations must come from
 unencrypted pools
Message-ID: <20200310184740.GA9745@lst.de>
References: <alpine.DEB.2.21.1912311738130.68206@chino.kir.corp.google.com> <b22416ec-cc28-3fd2-3a10-89840be173fa@amd.com> <alpine.DEB.2.21.2002280118461.165532@chino.kir.corp.google.com> <alpine.DEB.2.21.2003011535510.213582@chino.kir.corp.google.com> <alpine.DEB.2.21.2003011538040.213582@chino.kir.corp.google.com> <20200305154456.GC5332@lst.de> <alpine.DEB.2.21.2003061623060.27928@chino.kir.corp.google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.21.2003061623060.27928@chino.kir.corp.google.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Mar 06, 2020 at 04:36:07PM -0800, David Rientjes wrote:
> As a preliminary change to this series, I could move the atomic pools and 
> coherent_pool command line to a new kernel/dma/atomic_pools.c file with a 
> new CONFIG_DMA_ATOMIC_POOLS that would get "select"ed by CONFIG_DMA_REMAP 
> and CONFIG_AMD_MEM_ENCRYPT and call into dma_common_contiguous_remap() if 
> we have CONFIG_DMA_DIRECT_REMAP when adding pages to the pool.

Yes.  Although I'd just name it kernel/dma/pool.c and
CONFIG_DMA_COHERENT_POOL or so, as I plan to reuse the code for
architectures that just preallocate all coherent memory at boot time
as well.

> I think that's what you mean by splitting the pool from remapping, 
> otherwise we still have a full CONFIG_DMA_REMAP dependency here.  If you 
> had something else in mind, please let me know.  Thanks!

Yes, that is exactly what I meant.