This is a note to let you know that I've just added the patch titled
xen: Use correct masking in xen_swiotlb_alloc_coherent.
to the 3.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-use-correct-masking-in-xen_swiotlb_alloc_coherent.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b5031ed1be0aa419250557123633453753181643 Mon Sep 17 00:00:00 2001
From: Ronny Hegewald <[email protected]>
Date: Fri, 31 Aug 2012 09:57:52 +0000
Subject: xen: Use correct masking in xen_swiotlb_alloc_coherent.
From: Ronny Hegewald <[email protected]>
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 <[email protected]>
Signed-off-by: Stefano Panella <[email protected]>
Acked-By: David Vrabel <[email protected]>
Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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);
Patches currently in stable-queue which might be from [email protected]
are
queue-3.5/xen-use-correct-masking-in-xen_swiotlb_alloc_coherent.patch
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