From: Tom Lendacky <thomas.lendacky-5C7GfCeVMHo@public.gmane.org>
To: Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Radim Krčmář" <rkrcmar-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"Matt Fleming"
<matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>,
x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
"Alexander Potapenko"
<glider-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
"Larry Woodman"
<lwoodman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Jonathan Corbet" <corbet-T1hC0tSOHrs@public.gmane.org>,
linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kasan-dev-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org,
"Ingo Molnar" <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"Andrey Ryabinin"
<aryabinin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>,
"Rik van Riel" <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"Arnd Bergmann" <arnd-r2nGTMty4D4@public.gmane.org>,
"Andy Lutomirski" <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"Thomas Gleixner" <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
"Dmitry Vyukov" <dvyukov-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
"Paolo Bonzini"
<pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC PATCH v3 08/20] x86: Add support for early encryption/decryption of memory
Date: Wed, 16 Nov 2016 13:22:36 -0600 [thread overview]
Message-ID: <3a9e093a-9e80-8d2b-2615-56675cf6f147@amd.com> (raw)
In-Reply-To: <20161116104656.qz5wp33zzyja373r-fF5Pk5pvG8Y@public.gmane.org>
On 11/16/2016 4:46 AM, Borislav Petkov wrote:
> Btw, for your next submission, this patch can be split in two exactly
> like the commit message paragraphs are:
I think I originally had it that way, I don't know why I combined them.
I'll split them out.
>
> On Wed, Nov 09, 2016 at 06:36:10PM -0600, Tom Lendacky wrote:
>> Add support to be able to either encrypt or decrypt data in place during
>> the early stages of booting the kernel. This does not change the memory
>> encryption attribute - it is used for ensuring that data present in either
>> an encrypted or un-encrypted memory area is in the proper state (for
>> example the initrd will have been loaded by the boot loader and will not be
>> encrypted, but the memory that it resides in is marked as encrypted).
>
> Patch 2: users of the new memmap change
>
>> The early_memmap support is enhanced to specify encrypted and un-encrypted
>> mappings with and without write-protection. The use of write-protection is
>> necessary when encrypting data "in place". The write-protect attribute is
>> considered cacheable for loads, but not stores. This implies that the
>> hardware will never give the core a dirty line with this memtype.
>
> Patch 1: change memmap
>
> This makes this aspect of the patchset much clearer and is better for
> bisection.
>
>> Signed-off-by: Tom Lendacky <thomas.lendacky-5C7GfCeVMHo@public.gmane.org>
>> ---
>> arch/x86/include/asm/fixmap.h | 9 +++
>> arch/x86/include/asm/mem_encrypt.h | 15 +++++
>> arch/x86/include/asm/pgtable_types.h | 8 +++
>> arch/x86/mm/ioremap.c | 28 +++++++++
>> arch/x86/mm/mem_encrypt.c | 102 ++++++++++++++++++++++++++++++++++
>> include/asm-generic/early_ioremap.h | 2 +
>> mm/early_ioremap.c | 15 +++++
>> 7 files changed, 179 insertions(+)
>
> ...
>
>> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
>> index d642cc5..06235b4 100644
>> --- a/arch/x86/mm/mem_encrypt.c
>> +++ b/arch/x86/mm/mem_encrypt.c
>> @@ -14,6 +14,9 @@
>> #include <linux/init.h>
>> #include <linux/mm.h>
>>
>> +#include <asm/tlbflush.h>
>> +#include <asm/fixmap.h>
>> +
>> extern pmdval_t early_pmd_flags;
>>
>> /*
>> @@ -24,6 +27,105 @@ extern pmdval_t early_pmd_flags;
>> unsigned long sme_me_mask __section(.data) = 0;
>> EXPORT_SYMBOL_GPL(sme_me_mask);
>>
>> +/* Buffer used for early in-place encryption by BSP, no locking needed */
>> +static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
>> +
>> +/*
>> + * This routine does not change the underlying encryption setting of the
>> + * page(s) that map this memory. It assumes that eventually the memory is
>> + * meant to be accessed as encrypted but the contents are currently not
>> + * encrypted.
>> + */
>> +void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size)
>> +{
>> + void *src, *dst;
>> + size_t len;
>> +
>> + if (!sme_me_mask)
>> + return;
>> +
>> + local_flush_tlb();
>> + wbinvd();
>> +
>> + /*
>> + * There are limited number of early mapping slots, so map (at most)
>> + * one page at time.
>> + */
>> + while (size) {
>> + len = min_t(size_t, sizeof(sme_early_buffer), size);
>> +
>> + /* Create a mapping for non-encrypted write-protected memory */
>> + src = early_memremap_dec_wp(paddr, len);
>> +
>> + /* Create a mapping for encrypted memory */
>> + dst = early_memremap_enc(paddr, len);
>> +
>> + /*
>> + * If a mapping can't be obtained to perform the encryption,
>> + * then encrypted access to that area will end up causing
>> + * a crash.
>> + */
>> + BUG_ON(!src || !dst);
>> +
>> + memcpy(sme_early_buffer, src, len);
>> + memcpy(dst, sme_early_buffer, len);
>
> I still am missing the short explanation why we need the temporary buffer.
Ok, I'll add that.
>
>
> Oh, and we can save us the code duplication a little. Diff ontop of yours:
Yup, makes sense. I'll incorporate this.
Thanks,
Tom
>
> ---
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 06235b477d7c..50e2c4fc7338 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -36,7 +36,8 @@ static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
> * meant to be accessed as encrypted but the contents are currently not
> * encrypted.
> */
> -void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size)
> +static void __init noinline
> +__mem_enc_dec(resource_size_t paddr, unsigned long size, bool enc)
> {
> void *src, *dst;
> size_t len;
> @@ -54,15 +55,15 @@ void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size)
> while (size) {
> len = min_t(size_t, sizeof(sme_early_buffer), size);
>
> - /* Create a mapping for non-encrypted write-protected memory */
> - src = early_memremap_dec_wp(paddr, len);
> + src = (enc ? early_memremap_dec_wp(paddr, len)
> + : early_memremap_enc_wp(paddr, len));
>
> - /* Create a mapping for encrypted memory */
> - dst = early_memremap_enc(paddr, len);
> + dst = (enc ? early_memremap_enc(paddr, len)
> + : early_memremap_dec(paddr, len));
>
> /*
> - * If a mapping can't be obtained to perform the encryption,
> - * then encrypted access to that area will end up causing
> + * If a mapping can't be obtained to perform the dec/encryption,
> + * then (un-)encrypted access to that area will end up causing
> * a crash.
> */
> BUG_ON(!src || !dst);
> @@ -78,52 +79,14 @@ void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size)
> }
> }
>
> -/*
> - * This routine does not change the underlying encryption setting of the
> - * page(s) that map this memory. It assumes that eventually the memory is
> - * meant to be accessed as not encrypted but the contents are currently
> - * encrypted.
> - */
> -void __init sme_early_mem_dec(resource_size_t paddr, unsigned long size)
> +void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size)
> {
> - void *src, *dst;
> - size_t len;
> -
> - if (!sme_me_mask)
> - return;
> -
> - local_flush_tlb();
> - wbinvd();
> -
> - /*
> - * There are limited number of early mapping slots, so map (at most)
> - * one page at time.
> - */
> - while (size) {
> - len = min_t(size_t, sizeof(sme_early_buffer), size);
> -
> - /* Create a mapping for encrypted write-protected memory */
> - src = early_memremap_enc_wp(paddr, len);
> -
> - /* Create a mapping for non-encrypted memory */
> - dst = early_memremap_dec(paddr, len);
> -
> - /*
> - * If a mapping can't be obtained to perform the decryption,
> - * then un-encrypted access to that area will end up causing
> - * a crash.
> - */
> - BUG_ON(!src || !dst);
> -
> - memcpy(sme_early_buffer, src, len);
> - memcpy(dst, sme_early_buffer, len);
> -
> - early_memunmap(dst, len);
> - early_memunmap(src, len);
> + return __mem_enc_dec(paddr, size, true);
> +}
>
> - paddr += len;
> - size -= len;
> - }
> +void __init sme_early_mem_dec(resource_size_t paddr, unsigned long size)
> +{
> + return __mem_enc_dec(paddr, size, false);
> }
>
> void __init sme_early_init(void)
>
next prev parent reply other threads:[~2016-11-16 19:22 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
[not found] ` <1478827480.20881.142.camel-ZPxbGqLxI0U@public.gmane.org>
2016-11-14 16:51 ` Tom Lendacky
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
[not found] ` <20161110003610.3280.22043.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2016-11-16 10:46 ` Borislav Petkov
[not found] ` <20161116104656.qz5wp33zzyja373r-fF5Pk5pvG8Y@public.gmane.org>
2016-11-16 19:22 ` Tom Lendacky [this message]
2016-11-10 0:36 ` [RFC PATCH v3 09/20] x86: Insure that boot memory areas are mapped properly Tom Lendacky
[not found] ` <20161110003620.3280.20613.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2016-11-17 12:20 ` Borislav Petkov
2016-11-19 18:12 ` 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
[not found] ` <d5ebd13d-1278-8714-3f03-8ee7f04a2b38-5C7GfCeVMHo@public.gmane.org>
2016-11-15 18:17 ` Radim Krčmář
2016-11-15 20:33 ` Tom Lendacky
2016-11-15 15:16 ` Michael S. Tsirkin
[not found] ` <20161115171443-mutt-send-email-mst-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <20161122154137.z5vp3xcl5cpesuiz-fF5Pk5pvG8Y@public.gmane.org>
2016-11-22 20:41 ` Michael S. Tsirkin
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
[not found] ` <20161122192526.vg63jjhwsbjwex7i-fF5Pk5pvG8Y@public.gmane.org>
2016-11-29 18:00 ` Tom Lendacky
[not found] ` <20161110003426.3280.2999.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
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
[not found] ` <20161110003513.3280.12104.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2016-11-15 12:10 ` Joerg Roedel
2016-11-15 12:14 ` Borislav Petkov
2016-11-15 14:40 ` Tom Lendacky
[not found] ` <a4cc5b07-89e1-aaa0-1977-1de95883ba62-5C7GfCeVMHo@public.gmane.org>
2016-11-15 15:33 ` Borislav Petkov
[not found] ` <20161115153338.a2cxmatnpqcgiaiy-fF5Pk5pvG8Y@public.gmane.org>
2016-11-15 16:06 ` Tom Lendacky
2016-11-15 16:33 ` Borislav Petkov
2016-11-15 17:08 ` Tom Lendacky
[not found] ` <20161115121456.f4slpk4i2jl3e2ke-fF5Pk5pvG8Y@public.gmane.org>
2016-11-15 21:22 ` Tom Lendacky
2016-11-15 21:33 ` Borislav Petkov
2016-11-15 22:01 ` Tom Lendacky
[not found] ` <20161115121035.GD24857-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
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
[not found] ` <20161110003543.3280.99623.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2016-11-14 17:29 ` Borislav Petkov
2016-11-14 18:18 ` Tom Lendacky
2016-11-14 20:01 ` Borislav Petkov
2016-11-10 0:36 ` [RFC PATCH v3 10/20] Add support to access boot related data in the clear Tom Lendacky
2016-11-11 16:17 ` Kani, Toshimitsu
[not found] ` <1478880929.20881.148.camel-ZPxbGqLxI0U@public.gmane.org>
2016-11-14 16:24 ` Tom Lendacky
2016-11-17 15:55 ` Borislav Petkov
[not found] ` <20161117155543.vg3domfqm3bhp4f7-fF5Pk5pvG8Y@public.gmane.org>
2016-11-19 18:33 ` Tom Lendacky
2016-11-20 23:04 ` Borislav Petkov
[not found] ` <20161110003631.3280.73292.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
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
[not found] ` <20161110003655.3280.57333.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2016-11-17 17:39 ` Borislav Petkov
2016-11-19 18:48 ` Tom Lendacky
[not found] ` <6f1a16e4-5a84-20c0-4bd3-3be5ed933800-5C7GfCeVMHo@public.gmane.org>
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
[not found] ` <20161110003708.3280.29934.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2016-11-17 18:09 ` Borislav Petkov
2016-11-19 18:50 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 14/20] iommu/amd: Disable AMD IOMMU " Tom Lendacky
2016-11-14 16:32 ` Joerg Roedel
2016-11-14 16:48 ` 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
[not found] ` <20161110003826.3280.5546.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
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
[not found] ` <20161110003838.3280.23327.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
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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