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Subject: Re: [PATCH v5 09/32] x86/mm: Provide general kernel support for
 memory encryption
References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net>
 <20170418211754.10190.25082.stgit@tlendack-t1.amdoffice.net>
 <0106e3fc-9780-e872-2274-fecf79c28923@intel.com>
 <9fc79e28-ad64-1c2f-4c46-a4efcdd550b0@amd.com>
From: Dave Hansen <dave.hansen@intel.com>
Message-ID: <67926f62-a068-6114-92ee-39bc08488b32@intel.com>
Date: Mon, 24 Apr 2017 08:57:17 -0700
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To: Tom Lendacky <thomas.lendacky@amd.com>, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org
Cc: Rik van Riel <riel@redhat.com>, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <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>, Larry Woodman <lwoodman@redhat.com>, Brijesh Singh <brijesh.singh@amd.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>, Dave Young <dyoung@redhat.com>, Thomas Gleixner <tglx@linutronix.de>, Dmitry Vyukov <dvyukov@google.com>

On 04/24/2017 08:53 AM, Tom Lendacky wrote:
> On 4/21/2017 4:52 PM, Dave Hansen wrote:
>> On 04/18/2017 02:17 PM, Tom Lendacky wrote:
>>> @@ -55,7 +57,7 @@ static inline void copy_user_page(void *to, void
>>> *from, unsigned long vaddr,
>>>      __phys_addr_symbol(__phys_reloc_hide((unsigned long)(x)))
>>>
>>>  #ifndef __va
>>> -#define __va(x)            ((void *)((unsigned long)(x)+PAGE_OFFSET))
>>> +#define __va(x)            ((void *)(__sme_clr(x) + PAGE_OFFSET))
>>>  #endif
>>
>> It seems wrong to be modifying __va().  It currently takes a physical
>> address, and this modifies it to take a physical address plus the SME
>> bits.
> 
> This actually modifies it to be sure the encryption bit is not part of
> the physical address.

If SME bits make it this far, we have a bug elsewhere.  Right?  Probably
best not to paper over it.

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