From: Borislav Petkov <bp@alien8.de>
To: Tom Lendacky <thomas.lendacky@amd.com>
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 15/20] x86: Check for memory encryption on the APs
Date: Tue, 22 Nov 2016 20:25:26 +0100 [thread overview]
Message-ID: <20161122192526.vg63jjhwsbjwex7i@pd.tnic> (raw)
In-Reply-To: <20161110003740.3280.57300.stgit@tlendack-t1.amdoffice.net>
On Wed, Nov 09, 2016 at 06:37:40PM -0600, Tom Lendacky wrote:
> Add support to check if memory encryption is active in the kernel and that
> it has been enabled on the AP. If memory encryption is active in the kernel
> but has not been enabled on the AP then do not allow the AP to continue
> start up.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> arch/x86/include/asm/realmode.h | 12 ++++++++++++
> arch/x86/realmode/init.c | 4 ++++
> arch/x86/realmode/rm/trampoline_64.S | 19 +++++++++++++++++++
> 3 files changed, 35 insertions(+)
>
> diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
> index 230e190..850dbe0 100644
> --- a/arch/x86/include/asm/realmode.h
> +++ b/arch/x86/include/asm/realmode.h
> @@ -1,6 +1,15 @@
> #ifndef _ARCH_X86_REALMODE_H
> #define _ARCH_X86_REALMODE_H
>
> +/*
> + * Flag bit definitions for use with the flags field of the trampoline header
> + * when configured for X86_64
Let's use kernel nomenclature: "... of the trampoline header in the
CONFIG_X86_64 variant."
> + */
> +#define TH_FLAGS_SME_ENABLE_BIT 0
> +#define TH_FLAGS_SME_ENABLE BIT_ULL(TH_FLAGS_SME_ENABLE_BIT)
BIT() is the proper one for u32 flags variable.
> +
> +#ifndef __ASSEMBLY__
> +
> #include <linux/types.h>
> #include <asm/io.h>
>
> @@ -38,6 +47,7 @@ struct trampoline_header {
> u64 start;
> u64 efer;
> u32 cr4;
> + u32 flags;
> #endif
> };
>
> @@ -69,4 +79,6 @@ static inline size_t real_mode_size_needed(void)
> void set_real_mode_mem(phys_addr_t mem, size_t size);
> void reserve_real_mode(void);
>
> +#endif /* __ASSEMBLY__ */
> +
> #endif /* _ARCH_X86_REALMODE_H */
> diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
> index 44ed32a..a8e7ebe 100644
> --- a/arch/x86/realmode/init.c
> +++ b/arch/x86/realmode/init.c
> @@ -101,6 +101,10 @@ static void __init setup_real_mode(void)
> trampoline_cr4_features = &trampoline_header->cr4;
> *trampoline_cr4_features = mmu_cr4_features;
>
> + trampoline_header->flags = 0;
> + if (sme_me_mask)
> + trampoline_header->flags |= TH_FLAGS_SME_ENABLE;
> +
> trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
> trampoline_pgd[0] = trampoline_pgd_entry.pgd;
> trampoline_pgd[511] = init_level4_pgt[511].pgd;
> diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
> index dac7b20..94e29f4 100644
> --- a/arch/x86/realmode/rm/trampoline_64.S
> +++ b/arch/x86/realmode/rm/trampoline_64.S
> @@ -30,6 +30,7 @@
> #include <asm/msr.h>
> #include <asm/segment.h>
> #include <asm/processor-flags.h>
> +#include <asm/realmode.h>
> #include "realmode.h"
>
> .text
> @@ -92,6 +93,23 @@ ENTRY(startup_32)
> movl %edx, %fs
> movl %edx, %gs
>
> + /* Check for memory encryption support */
> + bt $TH_FLAGS_SME_ENABLE_BIT, pa_tr_flags
> + jnc .Ldone
> + movl $MSR_K8_SYSCFG, %ecx
> + rdmsr
> + bt $MSR_K8_SYSCFG_MEM_ENCRYPT_BIT, %eax
> + jc .Ldone
> +
> + /*
> + * Memory encryption is enabled but the MSR has not been set on this
> + * CPU so we can't continue
Can this ever happen?
I mean, we set TH_FLAGS_SME_ENABLE when sme_me_mask is set and this
would have happened only if the BSP has MSR_K8_SYSCFG[23] set.
How is it possible that that bit won't be set on some of the APs but set
on the BSP?
I'd assume the BIOS is doing a consistent setting everywhere...
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2016-11-22 19:25 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
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 [this message]
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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