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

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Jan 19, 2018 at 04:35:24PM +0100, 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@suse.de>
> > >>>>
> > >>>
> > >>> 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 (“x86/mm: Clean up register saving in the __enc_copy() assembly code”)
> >   bacf6b499e11 (“x86/mm: Use a struct to reduce parameters for SME PGD mapping”)
> >   2b5d00b6c2cd (“x86/mm: Centralize PMD flags in sme_encrypt_kernel()”)
> >   cc5f01e28d6c (“x86/mm: Prepare sme_encrypt_kernel() for PAGE aligned encryption”)
> >   107cd2532181 (“x86/mm: Encrypt the initrd earlier for BSP microcode update”)
> > 
> > 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.
> 
> And are any of these needed in older kernels like 4.4 and 4.9?

Oh nevermind, this is for a feature that is not in older kernels, sorry
for the noise.

greg k-h