Re: [PATCH v3 0/5] x86: SME: BSP/SME microcode update fix

[Gabriel C]

2018-01-19 16:56 GMT+01:00 Tom Lendacky <thomas.lendacky@xxxxxxx>:
> On 1/19/2018 9:35 AM, Greg Kroah-Hartman wrote:
>> On Fri, Jan 19, 2018 at 09:27:47AM -0600, Tom Lendacky wrote:
>>> On 1/19/2018 9:11 AM, Greg Kroah-Hartman wrote:
>>>> On Fri, Jan 19, 2018 at 09:03:52AM -0600, Tom Lendacky wrote:
>>>>> On 1/15/2018 4:47 PM, Gabriel C wrote:
>>>>>> On 11.01.2018 19:33, Borislav Petkov wrote:
>>>>>>> On Wed, Jan 10, 2018 at 01:25:45PM -0600, Tom Lendacky wrote:
>>>>>>>> This patch series addresses an issue when SME is active and the BSP
>>>>>>>> is attempting to check for and load microcode during load_ucode_bsp().
>>>>>>>> Since the initrd has not been decrypted (yet) and the virtual address
>>>>>>>> of the initrd treats the memory as encrypted, the CPIO archive parsing
>>>>>>>> fails to locate the microcode.
>>>>>>>>
>>>>>>>> This series moves the encryption of the initrd into the early boot code
>>>>>>>> and encrypts it at the same time that the kernel is encrypted.  Since
>>>>>>>> the initrd is now encrypted, the CPIO archive parsing succeeds in
>>>>>>>> properly locating the microcode.
>>>>>>>>
>>>>>>>> The following patches are included in this fix:
>>>>>>>> - Cleanup register saving in arch/x86/mm/mem_encrypt_boot.S
>>>>>>>> - Reduce parameters and complexity for creating the SME PGD mappings
>>>>>>>> - Centralize the use of the PMD flags used in sme_encrypt_kernel() in
>>>>>>>>    preparation for using PTE flags also.
>>>>>>>> - Prepare sme_encrypt_kernel() to handle PAGE aligned encryption, not
>>>>>>>>    just 2MB large page aligned encryption.
>>>>>>>> - Encrypt the initrd in sme_encrypt_kernel() when the kernel is being
>>>>>>>>    encrypted.
>>>>>>>>
>>>>>>>> This patch series is based on tip/master.
>>>>>>>>
>>>>>>>> ---
>>>>>>>>
>>>>>>>> Changes from v2:
>>>>>>>> - General code cleanup based on feedback.
>>>>>>>>
>>>>>>>> Changes from v1:
>>>>>>>> - Additional patch to cleanup the register saving performed in
>>>>>>>>    arch/x86/mm/mem_encrypt_boot.S in prep for changes made in the
>>>>>>>>    remainder of the patchset.
>>>>>>>> - Additional patch to reduce parameters and complexity for creating the
>>>>>>>>    SME PGD mappings by introducing and using a structure for referencing
>>>>>>>>    the PGD to populate, the pagetable allocation area, the
>>>>>>>> virtual/physical
>>>>>>>>    addresses being mapped and the pagetable flags to be used.
>>>>>>>> - Consolidate PMD/PTE mapping code to reduce duplication.
>>>>>>>>
>>>>>>>> Tom Lendacky (5):
>>>>>>>>        x86/mm: Cleanup register saving in mem_encrypt_boot.S
>>>>>>>>        x86/mm: Use a struct to reduce parameters for SME PGD mapping
>>>>>>>>        x86/mm: Centralize PMD flags in sme_encrypt_kernel()
>>>>>>>>        x86/mm: Prepare sme_encrypt_kernel() for PAGE aligned encryption
>>>>>>>>        x86/mm: Encrypt the initrd earlier for BSP microcode update
>>>>>>>>
>>>>>>>>
>>>>>>>>   arch/x86/include/asm/mem_encrypt.h |    4
>>>>>>>>   arch/x86/kernel/head64.c           |    4
>>>>>>>>   arch/x86/kernel/setup.c            |   10 -
>>>>>>>>   arch/x86/mm/mem_encrypt.c          |  356
>>>>>>>> ++++++++++++++++++++++++++----------
>>>>>>>>   arch/x86/mm/mem_encrypt_boot.S     |   80 ++++----
>>>>>>>>   5 files changed, 308 insertions(+), 146 deletions(-)
>>>>>>>
>>>>>>> All 5:
>>>>>>>
>>>>>>> Reviewed-by: Borislav Petkov <bp@xxxxxxx>
>>>>>>>
>>>>>>
>>>>>> Guys , are these patches going to be part of 4.15 ?
>>>>>>
>>>>>> With mem_encrypt=on without these patches microcode loading doesn't
>>>>>> work right. Also @stable 4.14 would need the fixes too.
>>>>>
>>>>> It looks like these patches have been pulled into 4.15.  I did forget
>>>>> to cc stable, so I'll follow-up with a separate email to have these
>>>>> back-ported to the 4.14 stable tree.
>>>>
>>>> What are the git commit ids?   That's all I need :)
>>>
>>> Hi Greg,
>>>
>>> Here are the commit ids:
>>>   1303880179e6 (âx86/mm: Clean up register saving in the __enc_copy() assembly codeâ)
>>>   bacf6b499e11 (âx86/mm: Use a struct to reduce parameters for SME PGD mappingâ)
>>>   2b5d00b6c2cd (âx86/mm: Centralize PMD flags in sme_encrypt_kernel()â)
>>>   cc5f01e28d6c (âx86/mm: Prepare sme_encrypt_kernel() for PAGE aligned encryptionâ)
>>>   107cd2532181 (âx86/mm: Encrypt the initrd earlier for BSP microcode updateâ)
>>>
>>> The last commit won't apply cleanly on 4.14.  There was a change in
>>> arch/x86/kernel/setup.c for SEV support.  The actual patch to that file
>>> is very small it just removes the call to sme_early_encrypt() and the
>>> associated comment.  I can submit a new version of that patch if you
>>> want, just let me know.
>>
>> A backported version of that would be great, thanks.
>
> Ok, I'll send that out as soon as possible.  Since it is a changed patch
> I was planning to remove the Tested-by, Signed-off-by (except for my sign
> off), etc. or would you prefer I leave them in this case?
>

I tested the series on top 4.14.13/.14 already , the conflict is
trivial and easy to fix.

If you wish you can keep my Tested-by.

Regards,

Gabriel C