| From | Greg Kroah-Hartman <> | Subject | [ 102/108] xen: Use correct masking in xen_swiotlb_alloc_coherent. | Date | Wed, 12 Sep 2012 16:29:40 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.5-stable review patch. If anyone has any objections, please let me know.
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From: Ronny Hegewald <ronny.hegewald@online.de>
commit b5031ed1be0aa419250557123633453753181643 upstream.
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.html
Signed-off-by: Ronny Hegewald <ronny.hegewald@online.de> Signed-off-by: Stefano Panella <stefano.panella@citrix.com> Acked-By: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/xen/swiotlb-xen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -232,7 +232,7 @@ xen_swiotlb_alloc_coherent(struct device return ret; if (hwdev && hwdev->coherent_dma_mask) - dma_mask = hwdev->coherent_dma_mask; + dma_mask = dma_alloc_coherent_mask(hwdev, flags); phys = virt_to_phys(ret); dev_addr = xen_phys_to_bus(phys);
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