From: Tom Lendacky <thomas.lendacky@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org,
kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, iommu@lists.linux-foundation.org,
"Rik van Riel" <riel@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Jonathan Corbet" <corbet@lwn.net>,
"Matt Fleming" <matt@codeblueprint.co.uk>,
"Joerg Roedel" <joro@8bytes.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Larry Woodman" <lwoodman@redhat.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Alexander Potapenko" <glider@google.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Dmitry Vyukov" <dvyukov@google.com>
Subject: Re: [RFC PATCH v3 06/20] x86: Add support to enable SME during early boot processing
Date: Mon, 14 Nov 2016 12:18:44 -0600 [thread overview]
Message-ID: <178d7d21-ffbd-1083-9c64-f05378147e27@amd.com> (raw)
In-Reply-To: <20161114172930.27z7p2kytmhtcbsb@pd.tnic>
On 11/14/2016 11:29 AM, Borislav Petkov wrote:
> On Wed, Nov 09, 2016 at 06:35:43PM -0600, Tom Lendacky wrote:
>> This patch adds support to the early boot code to use Secure Memory
>> Encryption (SME). Support is added to update the early pagetables with
>> the memory encryption mask and to encrypt the kernel in place.
>>
>> The routines to set the encryption mask and perform the encryption are
>> stub routines for now with full function to be added in a later patch.
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>> arch/x86/kernel/Makefile | 2 ++
>> arch/x86/kernel/head_64.S | 35 ++++++++++++++++++++++++++++++++++-
>> arch/x86/kernel/mem_encrypt_init.c | 29 +++++++++++++++++++++++++++++
>> 3 files changed, 65 insertions(+), 1 deletion(-)
>> create mode 100644 arch/x86/kernel/mem_encrypt_init.c
>>
>> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
>> index 45257cf..27e22f4 100644
>> --- a/arch/x86/kernel/Makefile
>> +++ b/arch/x86/kernel/Makefile
>> @@ -141,4 +141,6 @@ ifeq ($(CONFIG_X86_64),y)
>>
>> obj-$(CONFIG_PCI_MMCONFIG) += mmconf-fam10h_64.o
>> obj-y += vsmp_64.o
>> +
>> + obj-y += mem_encrypt_init.o
>> endif
>> diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
>> index c98a559..9a28aad 100644
>> --- a/arch/x86/kernel/head_64.S
>> +++ b/arch/x86/kernel/head_64.S
>> @@ -95,6 +95,17 @@ startup_64:
>> jnz bad_address
>>
>> /*
>> + * Enable Secure Memory Encryption (if available). Save the mask
>> + * in %r12 for later use and add the memory encryption mask to %rbp
>> + * to include it in the page table fixups.
>> + */
>> + push %rsi
>> + call sme_enable
>> + pop %rsi
>
> Why %rsi?
>
> sme_enable() is void so no args in registers and returns in %rax.
>
> /me is confused.
The %rsi register can be clobbered by the called function so I'm saving
it since it points to the real mode data. I might be able to look into
saving it earlier and restoring it before needed, but I though this
might be clearer.
>
>> + movq %rax, %r12
>> + addq %r12, %rbp
>> +
>> + /*
>> * Fixup the physical addresses in the page table
>> */
>> addq %rbp, early_level4_pgt + (L4_START_KERNEL*8)(%rip)
>> @@ -117,6 +128,7 @@ startup_64:
>> shrq $PGDIR_SHIFT, %rax
>>
>> leaq (4096 + _KERNPG_TABLE)(%rbx), %rdx
>> + addq %r12, %rdx
>> movq %rdx, 0(%rbx,%rax,8)
>> movq %rdx, 8(%rbx,%rax,8)
>>
>> @@ -133,6 +145,7 @@ startup_64:
>> movq %rdi, %rax
>> shrq $PMD_SHIFT, %rdi
>> addq $(__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL), %rax
>> + addq %r12, %rax
>> leaq (_end - 1)(%rip), %rcx
>> shrq $PMD_SHIFT, %rcx
>> subq %rdi, %rcx
>> @@ -163,9 +176,21 @@ startup_64:
>> cmp %r8, %rdi
>> jne 1b
>>
>> - /* Fixup phys_base */
>> + /*
>> + * Fixup phys_base, remove the memory encryption mask from %rbp
>> + * to obtain the true physical address.
>> + */
>> + subq %r12, %rbp
>> addq %rbp, phys_base(%rip)
>>
>> + /*
>> + * The page tables have been updated with the memory encryption mask,
>> + * so encrypt the kernel if memory encryption is active
>> + */
>> + push %rsi
>> + call sme_encrypt_kernel
>> + pop %rsi
>
> Ditto.
>
>> +
>> movq $(early_level4_pgt - __START_KERNEL_map), %rax
>> jmp 1f
>> ENTRY(secondary_startup_64)
>> @@ -186,9 +211,17 @@ ENTRY(secondary_startup_64)
>> /* Sanitize CPU configuration */
>> call verify_cpu
>>
>> + push %rsi
>> + call sme_get_me_mask
>> + pop %rsi
>
> Ditto.
>
>> + movq %rax, %r12
>> +
>> movq $(init_level4_pgt - __START_KERNEL_map), %rax
>> 1:
>>
>> + /* Add the memory encryption mask to RAX */
>
> I think that should say something like:
>
> /*
> * Add the memory encryption mask to init_level4_pgt's physical address
> */
>
> or so...
Yup, I'll expand on the comment for this.
>
>> + addq %r12, %rax
>> +
>> /* Enable PAE mode and PGE */
>> movl $(X86_CR4_PAE | X86_CR4_PGE), %ecx
>> movq %rcx, %cr4
>> diff --git a/arch/x86/kernel/mem_encrypt_init.c b/arch/x86/kernel/mem_encrypt_init.c
>> new file mode 100644
>> index 0000000..388d6fb
>> --- /dev/null
>> +++ b/arch/x86/kernel/mem_encrypt_init.c
>
> So nothing in the commit message explains why we need a separate
> mem_encrypt_init.c file when we already have arch/x86/mm/mem_encrypt.c
> for all memory encryption code...
I can expand on the commit message about that. I was trying to keep the
early boot-related code separate from the main code in arch/x86/mm dir.
Thanks,
Tom
>
>> @@ -0,0 +1,29 @@
>> +/*
>> + * AMD Memory Encryption Support
>> + *
>> + * Copyright (C) 2016 Advanced Micro Devices, Inc.
>> + *
>> + * Author: Tom Lendacky <thomas.lendacky@amd.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/linkage.h>
>> +#include <linux/init.h>
>> +#include <linux/mem_encrypt.h>
>> +
>> +void __init sme_encrypt_kernel(void)
>> +{
>> +}
>> +
>> +unsigned long __init sme_get_me_mask(void)
>> +{
>> + return sme_me_mask;
>> +}
>> +
>> +unsigned long __init sme_enable(void)
>> +{
>> + return sme_me_mask;
>> +}
>
next prev parent reply other threads:[~2016-11-14 18:19 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-10 0:34 [RFC PATCH v3 00/20] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-11-10 0:34 ` [RFC PATCH v3 01/20] x86: Documentation for AMD Secure Memory Encryption (SME) Tom Lendacky
2016-11-10 10:51 ` Borislav Petkov
2016-11-14 17:15 ` Tom Lendacky
2016-11-10 0:34 ` [RFC PATCH v3 02/20] x86: Set the write-protect cache mode for full PAT support Tom Lendacky
2016-11-10 13:14 ` Borislav Petkov
2016-11-11 1:26 ` Kani, Toshimitsu
2016-11-14 16:51 ` Tom Lendacky
2016-11-10 0:34 ` [RFC PATCH v3 03/20] x86: Add the Secure Memory Encryption cpu feature Tom Lendacky
2016-11-11 11:53 ` Borislav Petkov
2016-11-10 0:35 ` [RFC PATCH v3 04/20] x86: Handle reduction in physical address size with SME Tom Lendacky
2016-11-15 12:10 ` Joerg Roedel
2016-11-15 12:14 ` Borislav Petkov
2016-11-15 14:40 ` Tom Lendacky
2016-11-15 15:33 ` Borislav Petkov
2016-11-15 16:06 ` Tom Lendacky
2016-11-15 16:33 ` Borislav Petkov
2016-11-15 17:08 ` Tom Lendacky
2016-11-15 21:22 ` Tom Lendacky
2016-11-15 21:33 ` Borislav Petkov
2016-11-15 22:01 ` Tom Lendacky
2016-11-15 14:32 ` Tom Lendacky
2016-11-10 0:35 ` [RFC PATCH v3 05/20] x86: Add Secure Memory Encryption (SME) support Tom Lendacky
2016-11-10 0:35 ` [RFC PATCH v3 06/20] x86: Add support to enable SME during early boot processing Tom Lendacky
2016-11-14 17:29 ` Borislav Petkov
2016-11-14 18:18 ` Tom Lendacky [this message]
2016-11-14 20:01 ` Borislav Petkov
2016-11-10 0:35 ` [RFC PATCH v3 07/20] x86: Provide general kernel support for memory encryption Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 08/20] x86: Add support for early encryption/decryption of memory Tom Lendacky
2016-11-16 10:46 ` Borislav Petkov
2016-11-16 19:22 ` Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 09/20] x86: Insure that boot memory areas are mapped properly Tom Lendacky
2016-11-17 12:20 ` Borislav Petkov
2016-11-19 18:12 ` Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 10/20] Add support to access boot related data in the clear Tom Lendacky
2016-11-11 16:17 ` Kani, Toshimitsu
2016-11-14 16:24 ` Tom Lendacky
2016-11-17 15:55 ` Borislav Petkov
2016-11-19 18:33 ` Tom Lendacky
2016-11-20 23:04 ` Borislav Petkov
2016-12-07 13:19 ` Matt Fleming
2016-12-09 14:26 ` Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 11/20] x86: Add support for changing memory encryption attribute Tom Lendacky
2016-11-17 17:39 ` Borislav Petkov
2016-11-19 18:48 ` Tom Lendacky
2016-11-21 8:27 ` Borislav Petkov
2016-11-10 0:37 ` [RFC PATCH v3 12/20] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2016-11-17 18:09 ` Borislav Petkov
2016-11-19 18:50 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 13/20] x86: DMA support for memory encryption Tom Lendacky
2016-11-15 14:39 ` Radim Krčmář
2016-11-15 17:02 ` Tom Lendacky
2016-11-15 18:17 ` Radim Krčmář
2016-11-15 20:33 ` Tom Lendacky
2016-11-15 15:16 ` Michael S. Tsirkin
2016-11-15 18:29 ` Tom Lendacky
2016-11-15 19:16 ` Michael S. Tsirkin
2016-11-22 11:38 ` Borislav Petkov
2016-11-22 15:22 ` Michael S. Tsirkin
2016-11-22 15:41 ` Borislav Petkov
2016-11-22 20:41 ` Michael S. Tsirkin
2016-11-10 0:37 ` [RFC PATCH v3 14/20] iommu/amd: Disable AMD IOMMU if memory encryption is active Tom Lendacky
2016-11-14 16:32 ` Joerg Roedel
2016-11-14 16:48 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 15/20] x86: Check for memory encryption on the APs Tom Lendacky
2016-11-22 19:25 ` Borislav Petkov
2016-11-29 18:00 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 16/20] x86: Do not specify encrypted memory for video mappings Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 17/20] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 18/20] x86: Access the setup data through debugfs un-encrypted Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 19/20] x86: Add support to make use of Secure Memory Encryption Tom Lendacky
2016-11-24 12:50 ` Borislav Petkov
2016-11-29 18:40 ` Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 20/20] " Tom Lendacky
2016-11-22 18:58 ` Borislav Petkov
2016-11-26 20:47 ` Borislav Petkov
2016-11-29 18:48 ` Tom Lendacky
2016-11-29 19:56 ` Borislav Petkov
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