Re: [PATCH v4 06/17] PCI: add SIOV and IMS capability detection

[Jason Gunthorpe]

On Mon, Nov 16, 2020 at 07:31:49AM +0000, Tian, Kevin wrote:

> > The subdevices require PASID & IOMMU in native, but inside the guest there
> > is no
> > need for IOMMU unless you want to build SVM on top. subdevices work
> > without
> > any vIOMMU or hypercall in the guest. Only because they look like normal
> > PCI devices we could map interrupts to legacy MSIx.
> 
> Guest managed subdevices on PF/VF requires vIOMMU. 

Why? I've never heard we need vIOMMU for our existing SRIOV flows in
VMs??

Jason