Re: [PATCH kernel 4/9] dma/swiotlb: Stop forcing SWIOTLB for TDISP devices

[Jason Gunthorpe]

On Wed, Apr 15, 2026 at 04:32:14PM +1000, Alexey Kardashevskiy wrote:
> > > So the DMA API should see the DMA_ATTR_CC_DECRYPTED and setup the
> > > correct dma_dddr_t either by choosing the shared alias for the TDISP
> > > device's vTOM, or setting the C bit in a vIOMMU S1.
> > 
> > Something like that?
> > 
> > https://github.com/AMDESE/linux-kvm/commit/266a41a1ea746557eb63debce886ce2c98820667
> > 
> > With some little hacks I can make this tree do TDISP DMA to private or shared (swiotlb) memory by steering via this vTOM thing. Thanks,
> 
> Ping? Thanks,

That seems approx right, it is broadl similar to what ARM is
doing.. But the address map changes when switching to T=1 for AMD?

Jason