Subject: Re: [RFC Part1 PATCH v3 05/17] x86, realmode: Don't decrypt
 trampoline area under SEV
To: Borislav Petkov <bp@suse.de>, 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>, 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>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
        Christoph Lameter <cl@linux.com>
References: <20170724190757.11278-1-brijesh.singh@amd.com>
 <20170724190757.11278-6-brijesh.singh@amd.com>
 <20170726160304.GE30471@nazgul.tnic>
From: Tom Lendacky <thomas.lendacky@amd.com>
Message-ID: <c7f50d1e-4410-8ea2-d4d0-06de24a4c2e9@amd.com>
Date: Thu, 10 Aug 2017 08:03:12 -0500
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On 7/26/2017 11:03 AM, Borislav Petkov wrote:
>   Subject: x86/realmode: ...

Done.

> 
> 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."

Will do.

Thanks,
Tom

>