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

[Gabriel C]

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.


Regards,

Gabriel C