[Bug 1514038] [NEW] grub2 UEFI PXE loads kernel/initrd very very slowly.

[David Monro]

Public bug reported:

If I use the grub-mknetdir command with grub-efi-amd64 v 2.02~beta2-29
as follows:

grub-mknetdir -d /usr/lib/grub/x86_64-efi --net-
directory=/var/lib/tftpboot --subdir=grub2-efi

to generate a PXE environment, and then boot a UEFI VM (or physical box)
using this PXE environment, loading the kernel and initrd via TFTP takes
a very long time (several minutes). This is due to a bug where grub2
doesn't open the protocol stack in exclusive mode and therefore doesn't
actually end up receiving all the TFTP packets.

I have rebuilt the grub package with the attached patch (from fedora)
and this completely fixes the problem, and the kernel and initrd take
only a few seconds to load.

Cheers

David

** Affects: grub2 (Ubuntu)
     Importance: Undecided
         Status: New

** Patch added: "Patch from fedora which fixes the problem"
   https://bugs.launchpad.net/bugs/1514038/+attachment/4514683/+files/0138-reopen-SNP-protocol-for-exclusive-use-by-grub.patch

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https://bugs.launchpad.net/bugs/1514038

Title:
  grub2 UEFI  PXE loads kernel/initrd very very slowly.

Status in grub2 package in Ubuntu:
  New

Bug description:
  If I use the grub-mknetdir command with grub-efi-amd64 v 2.02~beta2-29
  as follows:

  grub-mknetdir -d /usr/lib/grub/x86_64-efi --net-
  directory=/var/lib/tftpboot --subdir=grub2-efi

  to generate a PXE environment, and then boot a UEFI VM (or physical
  box) using this PXE environment, loading the kernel and initrd via
  TFTP takes a very long time (several minutes). This is due to a bug
  where grub2 doesn't open the protocol stack in exclusive mode and
  therefore doesn't actually end up receiving all the TFTP packets.

  I have rebuilt the grub package with the attached patch (from fedora)
  and this completely fixes the problem, and the kernel and initrd take
  only a few seconds to load.

  Cheers

  David

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