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Subject[PATCH V2 2/2] x86/hyperv: Make swiotlb bounce buffer allocation not just from low pages
Date
From: Tianyu Lan <Tianyu.Lan@microsoft.com>

In Hyper-V Isolation VM, swiotlb bnounce buffer size maybe 1G at most
and there maybe no enough memory from 0 to 4G according to memory layout.
Devices in Isolation VM can use memory above 4G as DMA memory and call
swiotlb_alloc_from_low_pages() to allocate swiotlb bounce buffer not
limit from 0 to 4G.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
arch/x86/kernel/cpu/mshyperv.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 5a99f993e639..50ba4622c650 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -343,6 +343,7 @@ static void __init ms_hyperv_init_platform(void)
* use swiotlb bounce buffer for dma transaction.
*/
swiotlb_force = SWIOTLB_FORCE;
+ swiotlb_set_alloc_from_low_pages(false);
#endif
}

--
2.25.1
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