On Tue, Nov 13, 2018 at 1:40 PM Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > On Tue, Nov 13, 2018 at 01:13:31PM +0200, Yehezkel Bernat wrote: > > On Tue, Nov 13, 2018 at 12:56 PM Mika Westerberg > > <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > > > > > > Just one point: > > > > Have you considered the option to add this property per (TBT?) device? > > > > > > No. ;-) > > > > > > You mean that one device uses security levels and another IOMMU? I don't > > > think it is possible without having some sort of table in the IOMMU > > > driver telling which devices it needs identity map and which not. Also > > > not sure what would be the benefit? > > > > For performance, of course. If some devices are considered safe (maybe a list > > communicated by platform firmware), the kernel may decide to configure them to > > passthrough the IOMMU (I think I remember there is such an option, but maybe I'm > > wrong.) > > At least I'm not aware of such an option. Windows for example enables > IOMMU for everything and I think macOS does the same. In Linux (with > these patches) we put all internal devices already passthrough mode so > things like internal graphics should not be affected. eGPUs are > different thing, though. So your point here is "currently we do the IOMMU decisions system-wide; we can always add a per-device attribute if needed"? Fair enough. So for this patch, Reviewed-by: Yehezkel Bernat <YehezkelShB@xxxxxxxxx>
