From: "Michael S. Tsirkin" <mst@redhat.com>
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>,
"Borislav Petkov" <bp@alien8.de>,
"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 13/20] x86: DMA support for memory encryption
Date: Tue, 15 Nov 2016 21:16:33 +0200 [thread overview]
Message-ID: <20161115211603-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <4d97f998-5835-f4e0-9840-7f7979251275@amd.com>
On Tue, Nov 15, 2016 at 12:29:35PM -0600, Tom Lendacky wrote:
> On 11/15/2016 9:16 AM, Michael S. Tsirkin wrote:
> > On Wed, Nov 09, 2016 at 06:37:23PM -0600, Tom Lendacky wrote:
> >> Since DMA addresses will effectively look like 48-bit addresses when the
> >> memory encryption mask is set, SWIOTLB is needed if the DMA mask of the
> >> device performing the DMA does not support 48-bits. SWIOTLB will be
> >> initialized to create un-encrypted bounce buffers for use by these devices.
> >>
> >> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> >> ---
> >> arch/x86/include/asm/dma-mapping.h | 5 ++-
> >> arch/x86/include/asm/mem_encrypt.h | 5 +++
> >> arch/x86/kernel/pci-dma.c | 11 ++++---
> >> arch/x86/kernel/pci-nommu.c | 2 +
> >> arch/x86/kernel/pci-swiotlb.c | 8 ++++-
> >> arch/x86/mm/mem_encrypt.c | 17 +++++++++++
> >> include/linux/swiotlb.h | 1 +
> >> init/main.c | 13 ++++++++
> >> lib/swiotlb.c | 58 +++++++++++++++++++++++++++++++-----
> >> 9 files changed, 103 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
> >> index 4446162..c9cdcae 100644
> >> --- a/arch/x86/include/asm/dma-mapping.h
> >> +++ b/arch/x86/include/asm/dma-mapping.h
>
> ..SNIP...
>
> >>
> >> +/*
> >> + * If memory encryption is active, the DMA address for an encrypted page may
> >> + * be beyond the range of the device. If bounce buffers are required be sure
> >> + * that they are not on an encrypted page. This should be called before the
> >> + * iotlb area is used.
> >
> > Makes sense, but I think at least a dmesg warning here
> > might be a good idea.
>
> Good idea. Should it be a warning when it is first being set up or
> a warning the first time the bounce buffers need to be used. Or maybe
> both?
>
> >
> > A boot flag that says "don't enable devices that don't support
> > encryption" might be a good idea, too, since most people
> > don't read dmesg output and won't notice the message.
>
> I'll look into this. It might be something that can be checked as
> part of the device setting its DMA mask or the first time a DMA
> API is used if the device doesn't explicitly set its mask.
>
> Thanks,
> Tom
>
> >
I think setup time is nicer if it's possible.
next prev parent reply other threads:[~2016-11-15 19:16 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 [this message]
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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