Re: [PATCH] iommu/dma: Handle MSI mappings separately
From: Christoph Hellwig <hch@infradead.org>
Date: 2019-07-30 06:28:46
Also in:
linux-iommu
On Mon, Jul 29, 2019 at 04:32:38PM +0100, Robin Murphy wrote:
MSI pages must always be mapped into a device's *current* domain, which
*might* be the default DMA domain, but might instead be a VFIO domain
with its own MSI cookie. This subtlety got accidentally lost in the
streamlining of __iommu_dma_map(), but rather than reintroduce more
complexity and/or special-casing, it turns out neater to just split this
path out entirely.
Since iommu_dma_get_msi_page() already duplicates much of what
__iommu_dma_map() does, it can easily just make the allocation and
mapping calls directly as well. That way we can further streamline the
helper back to exclusively operating on DMA domains.
Fixes: b61d271e59d7 ("iommu/dma: Move domain lookup into __iommu_dma_{map,unmap}")
Reported-by: Shameer Kolothum <redacted>
Reported-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>Hmm. I remember proposing this patch and you didn't like it because we could also have msis for a !IOMMU_DMA_IOVA_COOKIE cookie type. Or did we talk past each other? Note that if this change turns out to be valid we should also clean up the iommu_dma_free_iova() side. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel