linux-kernel - Re: [RFC PATCH] iommu/dma: Allow drivers to reserve an iova range

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200217080138.GB10342@infradead.org>
Date:   Mon, 17 Feb 2020 00:01:38 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     "Isaac J. Manjarres" <isaacm@...eaurora.org>
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Liam Mark <lmark@...eaurora.org>, joro@...tes.org,
        pratikp@...eaurora.org, kernel-team@...roid.com
Subject: Re: [RFC PATCH] iommu/dma: Allow drivers to reserve an iova range

On Fri, Feb 14, 2020 at 02:58:16PM -0800, Isaac J. Manjarres wrote:
> From: Liam Mark <lmark@...eaurora.org>
> 
> Some devices have a memory map which contains gaps or holes.
> In order for the device to have as much IOVA space as possible,
> allow its driver to inform the DMA-IOMMU layer that it should
> not allocate addresses from these holes.

Layering violation.  dma-iommu is the translation layer between the
DMA API and the IOMMU API.  And calls into it from drivers performing
DMA mappings need to go through the DMA API (and be documented there).