From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Wednesday, January 26, 2022 8:11 AM > > 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. Set swiotlb_ > alloc_from_low_pages to false in Isolation VM. > > 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..80a0423ac75d 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_alloc_from_low_pages = false; > #endif > } > > -- > 2.25.1 Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
