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Date:   Thu, 2 Jun 2022 14:47:02 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@iki.fi>
To:     Brijesh Singh <brijesh.singh@amd.com>
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Subject: Re: [PATCH Part2 RFC v4 04/40] x86/sev: Add the host SEV-SNP
 initialization support
Message-ID: <YpijNgA9ZJFOwF8k@kernel.org>
References: <20210707183616.5620-1-brijesh.singh@amd.com>
 <20210707183616.5620-5-brijesh.singh@amd.com>
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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?

BR, Jarkko