From: Joerg Roedel <joro@8bytes.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Christoph Hellwig <hch@lst.de>,
ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com,
kevin.tian@intel.com, mika.westerberg@linux.intel.com,
Ingo Molnar <mingo@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
pengfei.xu@intel.com,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
Jonathan Corbet <corbet@lwn.net>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Alan Cox <alan@linux.intel.com>,
Mika Westerberg <mika.westerberg@intel.com>
Subject: Re: [PATCH v6 5/8] iommu: Add bounce page APIs
Date: Thu, 15 Aug 2019 17:48:45 +0200 [thread overview]
Message-ID: <20190815154845.GA18327@8bytes.org> (raw)
In-Reply-To: <445624e7-eb57-8089-8eb3-8687a65b1258@linux.intel.com>
On Thu, Aug 15, 2019 at 02:15:32PM +0800, Lu Baolu wrote:
> iommu_map/unmap() APIs haven't parameters for dma direction and
> attributions. These parameters are elementary for DMA APIs. Say,
> after map, if the dma direction is TO_DEVICE and a bounce buffer is
> used, we must sync the data from the original dma buffer to the bounce
> buffer; In the opposite direction, if dma is FROM_DEVICE, before unmap,
> we need to sync the data from the bounce buffer onto the original
> buffer.
The DMA direction from DMA-API maps to the protections in iommu_map():
DMA_FROM_DEVICE: IOMMU_WRITE
DMA_TO_DEVICE: IOMMU_READ
DMA_BIDIRECTIONAL IOMMU_READ | IOMMU_WRITE
And for the sync DMA-API also has separate functions for either
direction. So I don't see why these extra functions are needed in the
IOMMU-API.
Regards,
Joerg
next prev parent reply other threads:[~2019-08-15 15:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 4:52 [PATCH v6 0/8] iommu: Bounce page for untrusted devices Lu Baolu
2019-07-30 4:52 ` [PATCH v6 1/8] iommu/vt-d: Don't switch off swiotlb if use direct dma Lu Baolu
2019-07-30 4:52 ` [PATCH v6 2/8] PCI: Add dev_is_untrusted helper Lu Baolu
2019-07-30 4:52 ` [PATCH v6 3/8] swiotlb: Split size parameter to map/unmap APIs Lu Baolu
2019-07-30 4:52 ` [PATCH v6 4/8] swiotlb: Zero out bounce buffer for untrusted device Lu Baolu
2019-07-30 4:52 ` [PATCH v6 5/8] iommu: Add bounce page APIs Lu Baolu
2019-08-14 8:38 ` Joerg Roedel
2019-08-15 6:15 ` Lu Baolu
2019-08-15 15:48 ` Joerg Roedel [this message]
2019-08-16 2:45 ` Lu Baolu
2019-08-16 4:46 ` Christoph Hellwig
2019-08-18 3:07 ` Lu Baolu
2019-07-30 4:52 ` [PATCH v6 6/8] iommu/vt-d: Check whether device requires bounce buffer Lu Baolu
2019-07-30 4:52 ` [PATCH v6 7/8] iommu/vt-d: Add trace events for device dma map/unmap Lu Baolu
2019-07-30 4:52 ` [PATCH v6 8/8] iommu/vt-d: Use bounce buffer for untrusted devices Lu Baolu
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