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,
"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>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Alexander Potapenko" <glider@google.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Dmitry Vyukov" <dvyukov@google.com>
Subject: Re: [RFC PATCH v2 15/20] iommu/amd: AMD IOMMU support for memory encryption
Date: Wed, 14 Sep 2016 08:45:44 -0500 [thread overview]
Message-ID: <27bc5c87-3a74-a1ee-55b1-7f19ec9cd6cc@amd.com> (raw)
In-Reply-To: <20160912114550.nwhtpmncwp22l7vy@pd.tnic>
On 09/12/2016 06:45 AM, Borislav Petkov wrote:
> On Mon, Aug 22, 2016 at 05:38:20PM -0500, Tom Lendacky wrote:
>> Add support to the AMD IOMMU driver to set the memory encryption mask if
>> memory encryption is enabled.
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>> arch/x86/include/asm/mem_encrypt.h | 2 ++
>> arch/x86/mm/mem_encrypt.c | 5 +++++
>> drivers/iommu/amd_iommu.c | 10 ++++++++++
>> 3 files changed, 17 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
>> index 384fdfb..e395729 100644
>> --- a/arch/x86/include/asm/mem_encrypt.h
>> +++ b/arch/x86/include/asm/mem_encrypt.h
>> @@ -36,6 +36,8 @@ void __init sme_early_init(void);
>> /* Architecture __weak replacement functions */
>> void __init mem_encrypt_init(void);
>>
>> +unsigned long amd_iommu_get_me_mask(void);
>> +
>> unsigned long swiotlb_get_me_mask(void);
>> void swiotlb_set_mem_dec(void *vaddr, unsigned long size);
>>
>> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
>> index 6b2e8bf..2f28d87 100644
>> --- a/arch/x86/mm/mem_encrypt.c
>> +++ b/arch/x86/mm/mem_encrypt.c
>> @@ -185,6 +185,11 @@ void __init mem_encrypt_init(void)
>> swiotlb_clear_encryption();
>> }
>>
>> +unsigned long amd_iommu_get_me_mask(void)
>> +{
>> + return sme_me_mask;
>> +}
>> +
>> unsigned long swiotlb_get_me_mask(void)
>> {
>> return sme_me_mask;
>> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>> index 96de97a..63995e3 100644
>> --- a/drivers/iommu/amd_iommu.c
>> +++ b/drivers/iommu/amd_iommu.c
>> @@ -166,6 +166,15 @@ struct dma_ops_domain {
>> static struct iova_domain reserved_iova_ranges;
>> static struct lock_class_key reserved_rbtree_key;
>>
>> +/*
>> + * Support for memory encryption. If memory encryption is supported, then an
>> + * override to this function will be provided.
>> + */
>> +unsigned long __weak amd_iommu_get_me_mask(void)
>> +{
>> + return 0;
>> +}
>
> So instead of adding a function each time which returns sme_me_mask
> for each user it has, why don't you add a single function which
> returns sme_me_mask in mem_encrypt.c and add an inline in the header
> mem_encrypt.h which returns 0 for the !CONFIG_AMD_MEM_ENCRYPT case.
Currently, mem_encrypt.h only lives in the arch/x86 directory so it
wouldn't be able to be included here without breaking other archs.
>
> This all is still funny because we access sme_me_mask directly for the
> different KERNEL_* masks but then you're adding an accessor function.
Because this lives outside of the arch/x86 I need to use the weak
function.
>
> So what you should do instead, IMHO, is either hide sme_me_mask
> altogether and use the accessor functions only (not sure if that would
> work in all cases) or expose sme_me_mask unconditionally and have it be
> 0 if CONFIG_AMD_MEM_ENCRYPT is not enabled so that it just works.
>
> Or is there a third, more graceful variant?
Is there a better way to do this given the support is only in x86?
Thanks,
Tom
>
next prev parent reply other threads:[~2016-09-14 13:46 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-22 22:35 [RFC PATCH v2 00/20] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-08-22 22:35 ` [RFC PATCH v2 01/20] x86: Documentation for AMD Secure Memory Encryption (SME) Tom Lendacky
2016-09-02 8:50 ` Borislav Petkov
2016-09-07 14:02 ` Tom Lendacky
2016-09-07 15:23 ` Borislav Petkov
2016-08-22 22:35 ` [RFC PATCH v2 02/20] x86: Set the write-protect cache mode for full PAT support Tom Lendacky
2016-08-25 3:58 ` Borislav Petkov
2016-08-22 22:35 ` [RFC PATCH v2 03/20] x86: Secure Memory Encryption (SME) build enablement Tom Lendacky
2016-09-02 11:03 ` Borislav Petkov
2016-09-07 14:03 ` Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 04/20] x86: Secure Memory Encryption (SME) support Tom Lendacky
2016-08-25 13:04 ` Thomas Gleixner
2016-08-30 13:19 ` Tom Lendacky
2016-08-30 14:57 ` Andy Lutomirski
2016-08-31 13:26 ` Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 05/20] x86: Add the Secure Memory Encryption cpu feature Tom Lendacky
2016-09-02 14:09 ` Borislav Petkov
2016-09-07 14:07 ` Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 06/20] x86: Handle reduction in physical address size with SME Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 07/20] x86: Provide general kernel support for memory encryption Tom Lendacky
2016-09-02 18:14 ` Borislav Petkov
2016-09-07 14:11 ` Tom Lendacky
2016-09-05 8:48 ` Borislav Petkov
2016-09-07 14:16 ` Tom Lendacky
2016-09-05 15:22 ` Borislav Petkov
2016-09-07 14:19 ` Tom Lendacky
2016-09-06 9:31 ` Borislav Petkov
2016-09-07 14:30 ` Tom Lendacky
2016-09-07 15:55 ` Borislav Petkov
2016-09-08 13:26 ` Tom Lendacky
2016-09-08 13:55 ` Borislav Petkov
2016-09-12 13:43 ` Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 08/20] x86: Extend the early_memmap support with additional attrs Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 09/20] x86: Add support for early encryption/decryption of memory Tom Lendacky
2016-09-06 16:12 ` Borislav Petkov
2016-08-22 22:37 ` [RFC PATCH v2 10/20] x86: Insure that memory areas are encrypted when possible Tom Lendacky
2016-09-09 15:53 ` Borislav Petkov
2016-09-12 15:05 ` Tom Lendacky
2016-09-12 16:33 ` Borislav Petkov
2016-09-14 14:11 ` Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 11/20] mm: Access BOOT related data in the clear Tom Lendacky
2016-09-09 16:38 ` Borislav Petkov
2016-09-12 15:14 ` Tom Lendacky
2016-09-12 16:35 ` Borislav Petkov
2016-09-12 16:55 ` Andy Lutomirski
2016-09-14 14:20 ` Tom Lendacky
2016-09-15 9:57 ` Matt Fleming
2016-09-15 16:52 ` Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 12/20] x86: Add support for changing memory encryption attribute Tom Lendacky
2016-09-09 17:23 ` Borislav Petkov
2016-09-12 15:41 ` Tom Lendacky
2016-09-12 16:41 ` Borislav Petkov
2016-08-22 22:37 ` [RFC PATCH v2 13/20] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2016-09-09 17:34 ` Borislav Petkov
2016-09-12 15:43 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 14/20] x86: DMA support for memory encryption Tom Lendacky
2016-09-12 10:58 ` Borislav Petkov
2016-09-14 13:36 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 15/20] iommu/amd: AMD IOMMU " Tom Lendacky
2016-09-12 11:45 ` Borislav Petkov
2016-09-14 13:45 ` Tom Lendacky [this message]
2016-09-14 14:41 ` Borislav Petkov
2016-09-15 16:57 ` Tom Lendacky
2016-09-16 7:08 ` Borislav Petkov
2016-08-22 22:38 ` [RFC PATCH v2 16/20] x86: Check for memory encryption on the APs Tom Lendacky
2016-09-12 12:17 ` Borislav Petkov
2016-09-14 13:50 ` Tom Lendacky
2016-09-12 16:43 ` Borislav Petkov
2016-09-14 14:12 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 17/20] x86: Do not specify encrypted memory for VGA mapping Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 18/20] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2016-09-12 14:35 ` Borislav Petkov
2016-09-14 14:02 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 19/20] x86: Access the setup data through debugfs un-encrypted Tom Lendacky
2016-09-12 16:59 ` Borislav Petkov
2016-09-14 14:29 ` Tom Lendacky
2016-09-14 14:51 ` Borislav Petkov
2016-09-15 17:08 ` Tom Lendacky
2016-09-16 7:11 ` Borislav Petkov
2016-08-22 22:39 ` [RFC PATCH v2 20/20] x86: Add support to make use of Secure Memory Encryption Tom Lendacky
2016-09-12 17:08 ` Borislav Petkov
2016-09-14 14:31 ` Tom Lendacky
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