Re: [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support

[Dave Hansen]

On 2/20/23 10:37, Michael Roth wrote:
> The RMP check is enforced as soon as SEV-SNP is enabled. Not every memory
> access requires an RMP check. In particular, the read accesses from the
> hypervisor do not require RMP checks because the data confidentiality is
> already protected via memory encryption. When hardware encounters an RMP
> checks failure, it raises a page-fault exception. If RMP check failure
> is due to the page-size mismatch, then split the large page to resolve
> the fault.

What does this all _mean_?

When does the kernel need to care about a "page-size mismatch"?