Re: [PATCH 3/4] iommu/vt-d: Do not enable ATS for external devices

2018-11-12 Thread Raj, Ashok
On Mon, Nov 12, 2018 at 07:06:27PM +0300, Mika Westerberg wrote: > Currently Linux automatically enables ATS (Address Translation Service) > for any device that supports it (and IOMMU is turned on). ATS is used to > accelerate DMA access as the device can cache translations locally so > there is

[PATCH 3/4] iommu/vt-d: Do not enable ATS for external devices

2018-11-12 Thread Mika Westerberg
Currently Linux automatically enables ATS (Address Translation Service) for any device that supports it (and IOMMU is turned on). ATS is used to accelerate DMA access as the device can cache translations locally so there is no need to do full translation on IOMMU side. However, as pointed out in