Re: [PATCH Part2 RFC v4 04/40] x86/sev: Add the host SEV-SNP initialization support

[Dr. David Alan Gilbert]

* Jarkko Sakkinen (jarkko.sakkinen@xxxxxx) wrote:
> On Wed, Jul 07, 2021 at 01:35:40PM -0500, Brijesh Singh wrote:
> > The memory integrity guarantees of SEV-SNP are enforced through a new
> > structure called the Reverse Map Table (RMP). The RMP is a single data
> > structure shared across the system that contains one entry for every 4K
> > page of DRAM that may be used by SEV-SNP VMs. The goal of RMP is to
> > track the owner of each page of memory. Pages of memory can be owned by
> > the hypervisor, owned by a specific VM or owned by the AMD-SP. See APM2
> > section 15.36.3 for more detail on RMP.
> > 
> > The RMP table is used to enforce access control to memory. The table itself
> > is not directly writable by the software. New CPU instructions (RMPUPDATE,
> > PVALIDATE, RMPADJUST) are used to manipulate the RMP entries.
> 
> What's the point of throwing out a set of opcodes, if there's
> no explanation what they do?

TBF They are described in the public document section linked in the previous
paragraph.

Dave
> BR, Jarkko
> 
-- 
Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK