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Date: Fri, 9 Sep 2016 19:34:42 +0200
From: Borislav Petkov <bp@...en8.de>
To: Tom Lendacky <thomas.lendacky@....com>
Cc: linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
kvm@...r.kernel.org, linux-doc@...r.kernel.org, x86@...nel.org,
linux-kernel@...r.kernel.org, kasan-dev@...glegroups.com,
linux-mm@...ck.org, iommu@...ts.linux-foundation.org,
Radim Krčmář <rkrcmar@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
Jonathan Corbet <corbet@....net>,
Matt Fleming <matt@...eblueprint.co.uk>,
Joerg Roedel <joro@...tes.org>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Ingo Molnar <mingo@...hat.com>,
Andy Lutomirski <luto@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Alexander Potapenko <glider@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [RFC PATCH v2 13/20] x86: Decrypt trampoline area if memory
encryption is active
On Mon, Aug 22, 2016 at 05:37:57PM -0500, Tom Lendacky wrote:
> When Secure Memory Encryption is enabled, the trampoline area must not
> be encrypted. A cpu running in real mode will not be able to decrypt
s/cpu/CPU/... always :-)
> memory that has been encrypted because it will not be able to use addresses
> with the memory encryption mask.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
> ---
> arch/x86/realmode/init.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
> index 5db706f1..f74925f 100644
> --- a/arch/x86/realmode/init.c
> +++ b/arch/x86/realmode/init.c
> @@ -6,6 +6,7 @@
> #include <asm/pgtable.h>
> #include <asm/realmode.h>
> #include <asm/tlbflush.h>
> +#include <asm/mem_encrypt.h>
>
> struct real_mode_header *real_mode_header;
> u32 *trampoline_cr4_features;
> @@ -130,6 +131,14 @@ static void __init set_real_mode_permissions(void)
> unsigned long text_start =
> (unsigned long) __va(real_mode_header->text_start);
>
> + /*
> + * If memory encryption is active, the trampoline area will need to
> + * be in non-encrypted memory in order to bring up other processors
Let's stick with either "unencrypted" - I'd prefer that one - or
"non-encrypted" nomenclature so that there's no distraction. I see both
versions in the patchset.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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