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 11/20] x86: Add support for changing memory encryption attribute
Date: Thu, 17 Nov 2016 18:39:45 +0100 [thread overview]
Message-ID: <20161117173945.gnar3arpyeeh5xm2@pd.tnic> (raw)
In-Reply-To: <20161110003655.3280.57333.stgit@tlendack-t1.amdoffice.net>
On Wed, Nov 09, 2016 at 06:36:55PM -0600, Tom Lendacky wrote:
> This patch adds support to be change the memory encryption attribute for
> one or more memory pages.
"Add support for changing ..."
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> arch/x86/include/asm/cacheflush.h | 3 +
> arch/x86/include/asm/mem_encrypt.h | 13 ++++++
> arch/x86/mm/mem_encrypt.c | 43 +++++++++++++++++++++
> arch/x86/mm/pageattr.c | 73 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 132 insertions(+)
...
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 411210d..41cfdf9 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -18,6 +18,7 @@
> #include <asm/fixmap.h>
> #include <asm/setup.h>
> #include <asm/bootparam.h>
> +#include <asm/cacheflush.h>
>
> extern pmdval_t early_pmd_flags;
> int __init __early_make_pgtable(unsigned long, pmdval_t);
> @@ -33,6 +34,48 @@ 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);
>
> +int sme_set_mem_enc(void *vaddr, unsigned long size)
> +{
> + unsigned long addr, numpages;
> +
> + if (!sme_me_mask)
> + return 0;
So those interfaces look duplicated to me: you have exported
sme_set_mem_enc/sme_set_mem_unenc which take @size and then you have
set_memory_enc/set_memory_dec which take numpages.
And then you're testing sme_me_mask in both.
What I'd prefer to have is only *two* set_memory_enc/set_memory_dec
which take size in bytes and one workhorse __set_memory_enc_dec() which
does it all. The user shouldn't have to care about numpages or size or
whatever.
Ok?
> +
> + addr = (unsigned long)vaddr & PAGE_MASK;
> + numpages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +
> + /*
> + * The set_memory_xxx functions take an integer for numpages, make
> + * sure it doesn't exceed that.
> + */
> + if (numpages > INT_MAX)
> + return -EINVAL;
> +
> + return set_memory_enc(addr, numpages);
> +}
> +EXPORT_SYMBOL_GPL(sme_set_mem_enc);
> +
> +int sme_set_mem_unenc(void *vaddr, unsigned long size)
> +{
> + unsigned long addr, numpages;
> +
> + if (!sme_me_mask)
> + return 0;
> +
> + addr = (unsigned long)vaddr & PAGE_MASK;
> + numpages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +
> + /*
> + * The set_memory_xxx functions take an integer for numpages, make
> + * sure it doesn't exceed that.
> + */
> + if (numpages > INT_MAX)
> + return -EINVAL;
> +
> + return set_memory_dec(addr, numpages);
> +}
> +EXPORT_SYMBOL_GPL(sme_set_mem_unenc);
> +
> /*
> * This routine does not change the underlying encryption setting of the
> * page(s) that map this memory. It assumes that eventually the memory is
> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
> index b8e6bb5..babf3a6 100644
> --- a/arch/x86/mm/pageattr.c
> +++ b/arch/x86/mm/pageattr.c
> @@ -1729,6 +1729,79 @@ int set_memory_4k(unsigned long addr, int numpages)
> __pgprot(0), 1, 0, NULL);
> }
>
> +static int __set_memory_enc_dec(struct cpa_data *cpa)
> +{
> + unsigned long addr;
> + int numpages;
> + int ret;
> +
> + /* People should not be passing in unaligned addresses */
> + if (WARN_ONCE(*cpa->vaddr & ~PAGE_MASK,
> + "misaligned address: %#lx\n", *cpa->vaddr))
> + *cpa->vaddr &= PAGE_MASK;
> +
> + addr = *cpa->vaddr;
> + numpages = cpa->numpages;
> +
> + /* Must avoid aliasing mappings in the highmem code */
> + kmap_flush_unused();
> + vm_unmap_aliases();
> +
> + ret = __change_page_attr_set_clr(cpa, 1);
> +
> + /* Check whether we really changed something */
> + if (!(cpa->flags & CPA_FLUSHTLB))
> + goto out;
That label is used only once - just "return ret;" here.
> + /*
> + * On success we use CLFLUSH, when the CPU supports it to
> + * avoid the WBINVD.
> + */
> + if (!ret && static_cpu_has(X86_FEATURE_CLFLUSH))
> + cpa_flush_range(addr, numpages, 1);
> + else
> + cpa_flush_all(1);
> +
> +out:
> + return ret;
> +}
> +
> +int set_memory_enc(unsigned long addr, int numpages)
> +{
> + struct cpa_data cpa;
> +
> + if (!sme_me_mask)
> + return 0;
> +
> + memset(&cpa, 0, sizeof(cpa));
> + cpa.vaddr = &addr;
> + cpa.numpages = numpages;
> + cpa.mask_set = __pgprot(_PAGE_ENC);
> + cpa.mask_clr = __pgprot(0);
> + cpa.pgd = init_mm.pgd;
You could move that...
> +
> + return __set_memory_enc_dec(&cpa);
> +}
> +EXPORT_SYMBOL(set_memory_enc);
> +
> +int set_memory_dec(unsigned long addr, int numpages)
> +{
> + struct cpa_data cpa;
> +
> + if (!sme_me_mask)
> + return 0;
> +
> + memset(&cpa, 0, sizeof(cpa));
> + cpa.vaddr = &addr;
> + cpa.numpages = numpages;
> + cpa.mask_set = __pgprot(0);
> + cpa.mask_clr = __pgprot(_PAGE_ENC);
> + cpa.pgd = init_mm.pgd;
... and that into __set_memory_enc_dec() too and pass in a "bool dec" or
"bool enc" or so which presets mask_set and mask_clr properly.
See above. I think two functions exported to other in-kernel users are
more than enough.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2016-11-17 17:39 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 [this message]
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
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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