Commit b5031ed1 authored by Committed by Konrad Rzeszutek Wilk
xen: Use correct masking in xen_swiotlb_alloc_coherent.
When running 32-bit pvops-dom0 and a driver tries to allocate a coherent DMA-memory the xen swiotlb-implementation returned memory beyond 4GB. The underlaying reason is that if the supplied driver passes in a DMA_BIT_MASK(64) ( hwdev->coherent_dma_mask is set to 0xffffffffffffffff) our dma_mask will be u64 set to 0xffffffffffffffff even if we set it to DMA_BIT_MASK(32) previously. Meaning we do not reset the upper bits. By using the dma_alloc_coherent_mask function - it does the proper casting and we get 0xfffffffff. This caused not working sound on a system with 4 GB and a 64-bit compatible sound-card with sets the DMA-mask to 64bit. On bare-metal and the forward-ported xen-dom0 patches from OpenSuse a coherent DMA-memory is always allocated inside the 32-bit address-range by calling dma_alloc_coherent_mask. This patch adds the same functionality to xen swiotlb and is a rebase of the original patch from Ronny Hegewald which never got upstream b/c the underlaying reason was not understood until now. The original email with the original patch is in: http://old-list-archives.xen.org/archives/html/xen-devel/2010-02/msg00038.html the original thread from where the discussion started is in: http://old-list-archives.xen.org/archives/html/xen-devel/2010-01/msg00928.htmlSigned-off-by: Ronny Hegewald <firstname.lastname@example.org> Signed-off-by: Stefano Panella <email@example.com> Acked-By: David Vrabel <firstname.lastname@example.org> Signed-off-by: Konrad Rzeszutek Wilk <email@example.com> CC: firstname.lastname@example.org
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