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>,
"Toshimitsu Kani" <toshi.kani@hpe.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Jonathan Corbet" <corbet@lwn.net>,
"Matt Fleming" <matt@codeblueprint.co.uk>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Brijesh Singh" <brijesh.singh@amd.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Alexander Potapenko" <glider@google.com>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Larry Woodman" <lwoodman@redhat.com>,
"Dmitry Vyukov" <dvyukov@google.com>
Subject: Re: [RFC PATCH v4 19/28] swiotlb: Add warnings for use of bounce buffers with SME
Date: Tue, 28 Feb 2017 17:19:51 -0600 [thread overview]
Message-ID: <9b5af67b-0969-5402-cc01-3ea98f41b748@amd.com> (raw)
In-Reply-To: <20170227175259.whl75utazbzxp7jo@pd.tnic>
On 2/27/2017 11:52 AM, Borislav Petkov wrote:
> On Thu, Feb 16, 2017 at 09:46:19AM -0600, Tom Lendacky wrote:
>> Add warnings to let the user know when bounce buffers are being used for
>> DMA when SME is active. Since the bounce buffers are not in encrypted
>> memory, these notifications are to allow the user to determine some
>> appropriate action - if necessary.
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>> arch/x86/include/asm/mem_encrypt.h | 11 +++++++++++
>> include/linux/dma-mapping.h | 11 +++++++++++
>> include/linux/mem_encrypt.h | 6 ++++++
>> lib/swiotlb.c | 3 +++
>> 4 files changed, 31 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
>> index 87e816f..5a17f1b 100644
>> --- a/arch/x86/include/asm/mem_encrypt.h
>> +++ b/arch/x86/include/asm/mem_encrypt.h
>> @@ -26,6 +26,11 @@ static inline bool sme_active(void)
>> return (sme_me_mask) ? true : false;
>> }
>>
>> +static inline u64 sme_dma_mask(void)
>> +{
>> + return ((u64)sme_me_mask << 1) - 1;
>> +}
>> +
>> void __init sme_early_encrypt(resource_size_t paddr,
>> unsigned long size);
>> void __init sme_early_decrypt(resource_size_t paddr,
>> @@ -53,6 +58,12 @@ static inline bool sme_active(void)
>> {
>> return false;
>> }
>> +
>> +static inline u64 sme_dma_mask(void)
>> +{
>> + return 0ULL;
>> +}
>> +
>> #endif
>>
>> static inline void __init sme_early_encrypt(resource_size_t paddr,
>> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
>> index 10c5a17..130bef7 100644
>> --- a/include/linux/dma-mapping.h
>> +++ b/include/linux/dma-mapping.h
>> @@ -10,6 +10,7 @@
>> #include <linux/scatterlist.h>
>> #include <linux/kmemcheck.h>
>> #include <linux/bug.h>
>> +#include <linux/mem_encrypt.h>
>>
>> /**
>> * List of possible attributes associated with a DMA mapping. The semantics
>> @@ -557,6 +558,11 @@ static inline int dma_set_mask(struct device *dev, u64 mask)
>>
>> if (!dev->dma_mask || !dma_supported(dev, mask))
>> return -EIO;
>> +
>> + if (sme_active() && (mask < sme_dma_mask()))
>> + dev_warn(dev,
>> + "SME is active, device will require DMA bounce buffers\n");
>> +
>
> Yes, definitely _once() here.
Setting the mask is a probe/init type event, so I think not having the
_once() would be better so that all devices that set a mask to something
less than the SME encryption mask would be identified. This isn't done
for every DMA, etc.
>
> It could be extended later to be per-device if the need arises.
>
> Also, a bit above in this function, we test if (ops->set_dma_mask) so
> device drivers which supply even an empty ->set_dma_mask will circumvent
> this check.
>
> It probably doesn't matter all that much right now because the
> only driver I see right now defining this method, though, is
> ethernet/intel/fm10k/fm10k_pf.c and some other arches' functionality
> which is unrelated here.
Device drivers don't supply set_dma_mask() since that is part of the
dma_map_ops structure. The fm10k_pf.c file function is unrelated to this
(it's part of an internal driver structure). The dma_map_ops structure
is setup by the arch or an iommu.
Thanks,
Tom
>
> But still...
>
>
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next prev parent reply other threads:[~2017-02-28 23:20 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-16 15:41 [RFC PATCH v4 00/28] x86: Secure Memory Encryption (AMD) Tom Lendacky
2017-02-16 15:42 ` [RFC PATCH v4 01/28] x86: Documentation for AMD Secure Memory Encryption (SME) Tom Lendacky
[not found] ` <20170216154211.19244.76656.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-16 17:56 ` Borislav Petkov
2017-02-16 19:48 ` Tom Lendacky
2017-02-16 15:42 ` [RFC PATCH v4 02/28] x86: Set the write-protect cache mode for full PAT support Tom Lendacky
[not found] ` <20170216154225.19244.96438.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-17 11:07 ` Borislav Petkov
2017-02-17 15:56 ` Tom Lendacky
2017-02-16 15:42 ` [RFC PATCH v4 03/28] x86: Add the Secure Memory Encryption CPU feature Tom Lendacky
[not found] ` <20170216154236.19244.7580.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-16 18:13 ` Borislav Petkov
2017-02-16 19:42 ` Tom Lendacky
[not found] ` <a1a6a6d7-3aac-3138-1e75-6160f0427a6b-5C7GfCeVMHo@public.gmane.org>
2017-02-16 20:06 ` Borislav Petkov
2017-02-16 15:42 ` [RFC PATCH v4 04/28] x86: Handle reduction in physical address size with SME Tom Lendacky
2017-02-17 11:04 ` Borislav Petkov
2017-02-16 15:43 ` [RFC PATCH v4 05/28] x86: Add Secure Memory Encryption (SME) support Tom Lendacky
2017-02-17 12:00 ` Borislav Petkov
2017-02-25 15:29 ` Borislav Petkov
2017-02-28 23:01 ` Tom Lendacky
2017-02-16 15:43 ` [RFC PATCH v4 06/28] x86: Add support to enable SME during early boot processing Tom Lendacky
[not found] ` <20170216154319.19244.7863.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 12:51 ` Borislav Petkov
2017-02-21 14:55 ` Tom Lendacky
[not found] ` <a23be4fa-d7ef-4e7a-5b6b-73e120a5ca80-5C7GfCeVMHo@public.gmane.org>
2017-02-21 15:10 ` Borislav Petkov
2017-02-16 15:43 ` [RFC PATCH v4 07/28] x86: Provide general kernel support for memory encryption Tom Lendacky
[not found] ` <20170216154332.19244.55451.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 15:21 ` Borislav Petkov
2017-02-21 17:18 ` Tom Lendacky
2017-02-22 12:08 ` Borislav Petkov
2017-02-20 18:38 ` Borislav Petkov
2017-02-22 16:43 ` Tom Lendacky
2017-02-22 18:13 ` Dave Hansen
2017-02-23 23:12 ` Tom Lendacky
2017-02-22 18:13 ` Dave Hansen
2017-02-16 15:43 ` [RFC PATCH v4 08/28] x86: Extend the early_memremap support with additional attrs Tom Lendacky
[not found] ` <20170216154348.19244.11884.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 15:43 ` Borislav Petkov
2017-02-22 15:42 ` Tom Lendacky
2017-02-16 15:43 ` [RFC PATCH v4 09/28] x86: Add support for early encryption/decryption of memory Tom Lendacky
[not found] ` <20170216154358.19244.6082.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 18:22 ` Borislav Petkov
2017-02-22 15:48 ` Tom Lendacky
2017-02-16 15:44 ` [RFC PATCH v4 10/28] x86: Insure that boot memory areas are mapped properly Tom Lendacky
[not found] ` <20170216154411.19244.99258.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 19:45 ` Borislav Petkov
2017-02-22 18:34 ` Tom Lendacky
2017-02-16 15:44 ` [RFC PATCH v4 11/28] x86: Add support to determine the E820 type of an address Tom Lendacky
[not found] ` <20170216154430.19244.95519.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 20:09 ` Borislav Petkov
2017-02-28 22:34 ` Tom Lendacky
2017-03-03 9:52 ` Borislav Petkov
2017-02-16 15:44 ` [RFC PATCH v4 12/28] efi: Add an EFI table address match function Tom Lendacky
2017-02-16 15:44 ` [RFC PATCH v4 13/28] efi: Update efi_mem_type() to return defined EFI mem types Tom Lendacky
2017-02-21 12:05 ` Matt Fleming
2017-02-23 17:27 ` Tom Lendacky
2017-02-24 9:57 ` Matt Fleming
2017-02-16 15:45 ` [RFC PATCH v4 14/28] Add support to access boot related data in the clear Tom Lendacky
[not found] ` <20170216154508.19244.58580.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-21 15:06 ` Borislav Petkov
2017-02-23 21:34 ` Tom Lendacky
2017-02-24 10:21 ` Borislav Petkov
2017-02-24 15:04 ` Tom Lendacky
2017-02-24 15:22 ` Borislav Petkov
2017-03-08 6:55 ` Dave Young
2017-03-17 19:50 ` Tom Lendacky
2017-02-16 15:45 ` [RFC PATCH v4 15/28] Add support to access persistent memory " Tom Lendacky
2017-03-17 22:58 ` Elliott, Robert (Persistent Memory)
2017-03-23 21:02 ` Tom Lendacky
2017-02-16 15:45 ` [RFC PATCH v4 16/28] x86: Add support for changing memory encryption attribute Tom Lendacky
2017-02-22 18:52 ` Borislav Petkov
2017-02-28 22:46 ` Tom Lendacky
2017-02-16 15:45 ` [RFC PATCH v4 17/28] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2017-02-16 15:46 ` [RFC PATCH v4 18/28] x86: DMA support for memory encryption Tom Lendacky
2017-02-25 17:10 ` Borislav Petkov
2017-03-06 17:47 ` Tom Lendacky
2017-02-16 15:46 ` [RFC PATCH v4 19/28] swiotlb: Add warnings for use of bounce buffers with SME Tom Lendacky
2017-02-17 15:59 ` Konrad Rzeszutek Wilk
2017-02-17 16:51 ` Tom Lendacky
2017-03-02 17:01 ` Paolo Bonzini
2017-02-27 17:52 ` Borislav Petkov
2017-02-28 23:19 ` Tom Lendacky [this message]
2017-03-01 11:17 ` Borislav Petkov
2017-02-16 15:46 ` [RFC PATCH v4 20/28] iommu/amd: Disable AMD IOMMU if memory encryption is active Tom Lendacky
2017-02-16 15:46 ` [RFC PATCH v4 21/28] x86: Check for memory encryption on the APs Tom Lendacky
[not found] ` <20170216154647.19244.18733.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-27 18:17 ` Borislav Petkov
2017-02-28 23:28 ` Tom Lendacky
[not found] ` <5f461d57-9232-1cb3-d4d9-9b8a39d00b12-5C7GfCeVMHo@public.gmane.org>
2017-03-01 11:17 ` Borislav Petkov
2017-02-16 15:47 ` [RFC PATCH v4 22/28] x86: Do not specify encrypted memory for video mappings Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 23/28] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 24/28] x86: Access the setup data through debugfs decrypted Tom Lendacky
2017-03-08 7:04 ` Dave Young
2017-03-17 19:54 ` Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 25/28] x86: Access the setup data through sysfs decrypted Tom Lendacky
2017-03-08 7:09 ` Dave Young
2017-03-17 20:09 ` Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 26/28] x86: Allow kexec to be used with SME Tom Lendacky
2017-02-17 15:57 ` Konrad Rzeszutek Wilk
2017-02-17 16:43 ` Tom Lendacky
2017-03-01 9:25 ` Dave Young
2017-03-01 9:27 ` Dave Young
2017-03-06 17:58 ` Tom Lendacky
2017-03-06 18:04 ` Tom Lendacky
2017-03-08 8:12 ` Dave Young
2017-02-28 10:35 ` Borislav Petkov
2017-03-01 15:36 ` Tom Lendacky
2017-02-16 15:48 ` [RFC PATCH v4 27/28] x86: Add support to encrypt the kernel in-place Tom Lendacky
[not found] ` <20170216154808.19244.475.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-03-01 17:36 ` Borislav Petkov
2017-03-02 18:30 ` Tom Lendacky
2017-03-02 18:51 ` Borislav Petkov
2017-02-16 15:48 ` [RFC PATCH v4 28/28] x86: Add support to make use of Secure Memory Encryption Tom Lendacky
2017-03-01 18:40 ` Borislav Petkov
2017-03-07 16:05 ` Tom Lendacky
2017-03-07 17:42 ` Borislav Petkov
2017-03-08 15:05 ` Borislav Petkov
[not found] ` <20170216154158.19244.66630.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-18 18:12 ` [RFC PATCH v4 00/28] x86: Secure Memory Encryption (AMD) Borislav Petkov
2017-02-21 15:09 ` Tom Lendacky
2017-02-21 17:42 ` Rik van Riel
[not found] ` <1487698965.17158.8.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-02-21 17:53 ` Borislav Petkov
2017-03-01 9:17 ` Dave Young
2017-03-01 17:51 ` Tom Lendacky
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