Re: [RFC v2 26/32] x86/mm: Move force_dma_unencrypted() to common code

[Kuppuswamy, Sathyanarayanan]

On 5/17/21 11:16 AM, Sean Christopherson wrote:
> What generic code needs access to SEV vs. TDX?  force_dma_unencrypted() is called
> from generic code, but its implementation is x86 specific.

When the hardening the drivers for TDX usage, we will have requirement to check
for is_protected_guest() to add code specific to protected guests. Since this will
be outside arch/x86, we need common framework for it.

Few examples are,
 * ACPI sleep driver uses WBINVD (when doing cache flushes). We want to skip it for
  TDX.
 * Forcing virtio to use dma API when running with untrusted host.

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer