xen: Add __GFP_DMA flag when xen_swiotlb_init gets free pages on ARM

Make sure that xen_swiotlb_init allocates buffers that are DMA capable
when at least one memblock is available below 4G. Otherwise we assume
that all devices on the SoC can cope with >4G addresses. We do this on
ARM and ARM64, where dom0 is mapped 1:1, so pfn == mfn in this case.

No functional changes on x86.

From: Chen Baozi <[email protected]>

Signed-off-by: Chen Baozi <[email protected]>
Signed-off-by: Stefano Stabellini <[email protected]>
Tested-by: Chen Baozi <[email protected]>
Acked-by: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: David Vrabel <[email protected]>
This commit is contained in:
Stefano Stabellini 2015-04-24 10:16:40 +01:00 • committed by David Vrabel
commit 8746515d7f
4 changed files with 22 additions and 1 deletions

View file

@ -235,7 +235,7 @@ retry:
#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order);
xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
if (xen_io_tlb_start)
break;
order--;