Re: [Qemu-devel] [PATCH v1 0/3] intel_iommu: support scalable mode

[Peter Xu]

On Tue, Mar 05, 2019 at 01:15:53PM +0800, Yi Sun wrote:

[...]

> > > w/o passthr
> > >     -device intel-iommu \
> > >     -netdev tap,id=net1,vhost=off|on \
> > >     -device virtio-net-pci,netdev=net1 \
> > 
> > Virtio devices require explicit enabling of DMAR:
> > 
> > https://wiki.qemu.org/Features/VT-d#With_Virtio_Devices
> > 
> > Otherwise it could probably still be bypassing the translation unit.
> > 
> > If you retest any, please feel free to skip some of the tests like
> > kernel build.  Quick netperf should work, which can save you time.
> > 
> Thanks! Just made a quick test. It works well. Please check below
> command.
> 
>     -device intel-iommu,intremap=on,device-iotlb=on \
>     -netdev tap,id=net1,vhost=off \
>     -device ioh3420,id=pcie.1,chassis=1 \
>     -device
> virtio-net-pci,bus=pcie.1,netdev=net1,disable-legacy=on,disable-modern=off,iommu_platform=on,ats=on
> \

Please also consider to try vhost=on with/without iommu=pt.

Regards,

-- 
Peter Xu