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Date: Tue, 7 Mar 2017 12:09:25 +0100
From: Borislav Petkov <bp@suse.de>
Subject: Re: [RFC PATCH v2 05/32] x86: Use encrypted access of BOOT related
 data with SEV
Message-ID: <20170307110925.zmo7gsflxhui4k7e@pd.tnic>
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To: Brijesh Singh <brijesh.singh@amd.com>
Cc: simon.guinot@sequanux.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, rkrcmar@redhat.com, matt@codeblueprint.co.uk, linux-pci@vger.kernel.org, linus.walleij@linaro.org, gary.hook@amd.com, linux-mm@kvack.org, paul.gortmaker@windriver.com, hpa@zytor.com, cl@linux.com, dan.j.williams@intel.com, aarcange@redhat.com, sfr@canb.auug.org.au, andriy.shevchenko@linux.intel.com, herbert@gondor.apana.org.au, bhe@redhat.com, xemul@parallels.com, joro@8bytes.org, x86@kernel.org, peterz@infradead.org, piotr.luc@intel.com, mingo@redhat.com, msalter@redhat.com, ross.zwisler@linux.intel.com, dyoung@redhat.com, thomas.lendacky@amd.com, jroedel@suse.de, keescook@chromium.org, arnd@arndb.de, toshi.kani@hpe.com, mathieu.desnoyers@efficios.com, luto@kernel.org, devel@linuxdriverproject.org, bhelgaas@google.com, tglx@linutronix.de, mchehab@kernel.org, iamjoonsoo.kim@lge.com, labbott@fedoraproject.org, tony.luck@intel.com, alexandre.bounine@idt.com, kuleshovmail@gmail.com, linux-kernel@vger.kernel.org, mcgrof@kernel.org, mst@redhat.com, linux-crypto@vger.kernel.org, tj@kernel.org, pbonzini@redhat.com, akpm@linux-foundation.org, davem@davemloft.net

On Thu, Mar 02, 2017 at 10:12:59AM -0500, Brijesh Singh wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
> 
> When Secure Encrypted Virtualization (SEV) is active, BOOT data (such as
> EFI related data, setup data) is encrypted and needs to be accessed as
> such when mapped. Update the architecture override in early_memremap to
> keep the encryption attribute when mapping this data.

This could also explain why persistent memory needs to be accessed
decrypted with SEV.

In general, what the difference in that aspect is in respect to SME. And
I'd write that in the comment over the function. And not say "E820 areas
are checked in making this determination." because that is visible but
say *why* we need to check those ranges and determine access depending
on their type.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix ImendA?rffer, Jane Smithard, Graham Norton, HRB 21284 (AG NA 1/4 rnberg)
-- 

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