[Bug 1716424] [grub2/xenial] possible regression found

[Ubuntu Foundations Team Bug Bot]

As a part of the Stable Release Updates quality process a search for
Launchpad bug reports using the version of grub2 from xenial-proposed
was performed and bug 1719271 was found.  Please investigate this bug
report to ensure that a regression will not be created by this SRU. In
the event that this is not a regression remove the "verification-failed"
tag from this bug report and add the tag "bot-stop-nagging" to bug
1719271 (not this bug). Thanks!

** Tags added: verification-failed

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https://bugs.launchpad.net/bugs/1716424

Title:
  correctly parse PMEM memory ranges to pass it to the kernel

Status in grub2 package in Ubuntu:
  Fix Released
Status in grub2-signed package in Ubuntu:
  Fix Released
Status in grub2 source package in Xenial:
  Fix Committed
Status in grub2-signed source package in Xenial:
  Fix Committed
Status in grub2 source package in Zesty:
  Triaged
Status in grub2-signed source package in Zesty:
  New
Status in grub2 source package in Artful:
  Fix Released
Status in grub2-signed source package in Artful:
  Fix Released

Bug description:
  [Impact]
  If trying to boot a system with PMEM:

  "Unknown memory type 14, considering reserved"

  The system will then not have access to EFIPresistentMemory ranges,
  because grub could not hand them over to the kernel to use. The
  resulting system would be missing a /dev/pmemN device.

  Grub requires 4 cherry-picked commits:

      - debian/patches/git_pmem_really_mark_mem_reserved_3d2c8048.patch
      - debian/patches/git_pmem_translate_persistent_type_76ce1de7.patch
      - debian/patches/git_pmem_mmap_handle_pmem_c79c59f1.patch
      - debian/patches/git_pmem_efiemu_handle_pmem_ae3b83a4.patch

  
  [Test case]
  - Boot PMEM-enabled system with updated grub

  [Regression Potential]
  This changes handling of memory ranges in grub, and may lead to incorrectly passing memory to the kernel, or otherwise allowing allocation of memory within reserved ranges. This would typically lead to a failure to boot the kernel, or missing memory-based devices (such a missing /dev/pmem0).

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