Re: [PATCH v2 0/4] Have TTM support SEV encryption with coherent memory

On Tue, Sep 03, 2019 at 03:15:00PM +0200, Thomas Hellström (VMware) wrote:

With SEV memory encryption and in some cases also with SME memory encryption, coherent memory is unencrypted. In those cases, TTM doesn't set up the correct page protection. Fix this by having the TTM coherent page allocator call into the platform code to determine whether coherent memory is encrypted or not, and modify the page protection if it is not.

v2:

• Use force_dma_unencrypted() rather than sev_active() to catch also the special SME encryption cases.

We should probably cc Christoph Hellwig on this ... better to hear his screams before merging than afterwards. As much as I don't support screaming maintainers, that seems the least bad option here. -Daniel