From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> --- 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
