illumos gate

Andy Fiddaman wrote:

When writing an EFI label to disk, efi_write() also creates a protective MBR (PMBR). This PMBR contains a single partition which spans the entire disk (in so far as can be addressed in an MBR) and by default it places the partition in the first slot within the MBR and does not mark it as active.

Some systems have firmware bugs that mean that they will not boot from an EFI-labelled disk with a PMBR in this configuration. The workaround is to place the partition entry in a different slot and/or to mark the partition as active. The FreeBSD installer makes these changes for particular systems - see http://src.illumos.org/source/xref/freebsd-head/usr.sbin/bsdinstall/scripts/auto#179
This came up at FOSDEM when trying to install OmniOS on a Lenovo X1 laptop - as luck would have it, the FreeBSD table was adjacent and helped to debug the problem.

illumos should have a way of customising the PMBR parameters so that these workarounds can be implemented in installers.

Yes this is an issue and have been waiting for test case. Thanks for attending it.

I’m not using the laptop often so once there is a fix I can test it.

Almost ready for RTI so here's some of the testing I've performed for the record:

libefi:

reaper# grep Dell /usr/share/hwdata/efi.fixes | tail -1
sys.manufacturer="Dell Inc." sys.product="PowerEdge R730" mb.version=A04 pmbr_active=1 pmbr_slot=3

reaper# zpool create test c0t13d1
reaper# fdisk -W - c0t13d1p0 | tail -5
* Id    Act  Bhead  Bsect  Bcyl    Ehead  Esect  Ecyl    Rsect      Numsect
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  238   128  255    63     1023    255    63     1023    1          62499999

reaper# zpool replace test c0t{13,14}d1
reaper# fdisk -W - c0t14d1p0 | tail -5
* Id    Act  Bhead  Bsect  Bcyl    Ehead  Esect  Ecyl    Rsect      Numsect
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  238   128  255    63     1023    255    63     1023    1          62499999

reaper# sed -i '/PowerEdge/s/active=1/active=0/' /usr/share/hwdata/efi.fixes
reaper# zpool replace test c0t{14,13}d1
reaper# fdisk -W - c0t13d1p0 | tail -5
* Id    Act  Bhead  Bsect  Bcyl    Ehead  Esect  Ecyl    Rsect      Numsect
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  238   0    255    63     1023    255    63     1023    1          62499999

reaper# sed -i '/PowerEdge/s/slot=3/slot=1/' /usr/share/hwdata/efi.fixes
reaper# zpool replace test c0t{13,14}d1
reaper# fdisk -W - c0t14d1p0 | tail -5
* Id    Act  Bhead  Bsect  Bcyl    Ehead  Esect  Ecyl    Rsect      Numsect
  0     0    0      0      0       0      0      0       0          0
  238   0    255    63     1023    255    63     1023    1          62499999
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0

reaper# sed -i '/PowerEdge/s/^/#/' /usr/share/hwdata/efi.fixes
reaper# zpool replace test c0t{14,13}d1
reaper# fdisk -W - c0t13d1p0 | tail -5
* Id    Act  Bhead  Bsect  Bcyl    Ehead  Esect  Ecyl    Rsect      Numsect
  238   0    255    63     1023    255    63     1023    1          62499999
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0

fdisk:

reaper# zpool export test
reaper# fdisk -E 2:1 c0t13d1p0
reaper# fdisk -W - c0t13d1p0 | tail -5
* Id    Act  Bhead  Bsect  Bcyl    Ehead  Esect  Ecyl    Rsect      Numsect
  0     0    0      0      0       0      0      0       0          0
  0     0    0      0      0       0      0      0       0          0
  238   128  255    63     1023    255    63     1023    1          62499999
  0     0    0      0      0       0      0      0       0          0
reaper# zpool import test
reaper# zpool status test
  pool: test
 state: ONLINE
  scan: resilvered 86K in 0h0m with 0 errors on Mon Feb 12 10:46:49 2018
config:

        NAME        STATE     READ WRITE CKSUM
        test        ONLINE       0     0     0
          c0t13d1   ONLINE       0     0     0

errors: No known data errors

This forgot to add the libefi -> libsmbios dependency in usr/src/lib/Makefile; it doesn't seem to be causing build failures at the moment, but should be fixed anyway.