Re: `AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y` causes AMDGPU to fail on Ryzen: amdgpu: SME is not compatible with RAVEN

[Paul Menzel]

Dear Tom,


Am 11.10.21 um 15:27 schrieb Tom Lendacky:
> On 10/11/21 8:11 AM, Borislav Petkov wrote:
> > On Mon, Oct 11, 2021 at 03:05:33PM +0200, Paul Menzel wrote:
> > > I think, the IOMMU is enabled on the MSI B350M MORTAR, but otherwise, 
> > > yes
> > > this looks fine. The help text could also be updated to mention problems
> > > with AMD Raven devices.
> >
> > This is not only about Raven GPUs but, as Alex explained, pretty much
> > about every device which doesn't support a 48 bit DMA mask. I'll expand
> > that aspect in the changelog.
>
> In general, non-GPU devices that don't support a 48-bit DMA mask work 
> fine (assuming they have set their DMA mask appropriately). It really 
> depends on whether SWIOTLB will be able to satisfy the memory 
> requirements of the driver when the IOMMU is not enabled or in 
> passthrough mode. Since GPU devices need/use a lot of memory, that 
> becomes a problem.

How can I check that?


Kind regards,

Paul