Date: Wed, 26 Jul 2017 18:03:04 +0200
From: Borislav Petkov <bp@suse.de>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-efi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        kvm@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>, Tony Luck <tony.luck@intel.com>,
        Piotr Luc <piotr.luc@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Fenghua Yu <fenghua.yu@intel.com>, Lu Baolu <baolu.lu@linux.intel.com>,
        Reza Arbab <arbab@linux.vnet.ibm.com>,
        David Howells <dhowells@redhat.com>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Laura Abbott <labbott@redhat.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Eric Biederman <ebiederm@xmission.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Jonathan Corbet <corbet@lwn.net>, Dave Airlie <airlied@redhat.com>,
        Kees Cook <keescook@chromium.org>, Paolo Bonzini <pbonzini@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
        Christoph Lameter <cl@linux.com>
Subject: Re: [RFC Part1 PATCH v3 05/17] x86, realmode: Don't decrypt
 trampoline area under SEV
Message-ID: <20170726160304.GE30471@nazgul.tnic>
References: <20170724190757.11278-1-brijesh.singh@amd.com>
 <20170724190757.11278-6-brijesh.singh@amd.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20170724190757.11278-6-brijesh.singh@amd.com>
User-Agent: Mutt/1.6.0 (2016-04-01)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1156
Lines: 36

 Subject: x86/realmode: ...

On Mon, Jul 24, 2017 at 02:07:45PM -0500, Brijesh Singh wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
> 
> When SEV is active the trampoline area will need to be in encrypted
> memory so only mark the area decrypted if SME is active.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  arch/x86/realmode/init.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
> index 1f71980..c7eeca7 100644
> --- a/arch/x86/realmode/init.c
> +++ b/arch/x86/realmode/init.c
> @@ -63,9 +63,11 @@ static void __init setup_real_mode(void)
>  	/*
>  	 * If SME is active, the trampoline area will need to be in
>  	 * decrypted memory in order to bring up other processors
> -	 * successfully.
> +	 * successfully. For SEV the trampoline area needs to be in
> +	 * encrypted memory, so only do this for SME.

Or simply say:

"It is not needed for SEV."

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--