Description

SPARC M8 or SPARC T8 series servers running Oracle VM Server for SPARC 3.5, 3.5.0.1, or 3.5.0.2 software might experience a kernel panic or another fatal error condition if a guest domain has the 'cpu-arch' property value set to 'migration-class1'. This applies to any domain migrated to a SPARC M8 or SPARC T8 series server with the 'cpu-arch' property having been set to 'migration-class1' on the source system, and to any domain created on a SPARC-M8 or SPARC-T8 platform with the 'cpu-arch' property set to 'migration-class1'.

The problem occurs when the Oracle Solaris kernel or any user application attempts to reference a 2 GB page on a SPARC M8 or SPARC T8 series server. The 'cpu-arch=migration-class1' setting incorrectly permits 2 GB page sizes on the underlying hardware platform, even though the SPARC M8 and SPARC T8 series servers do not support 2 GB page sizes.

Occurrence

This issue can occur in the following releases:

SPARC Platform (for SPARC M8 or SPARC T8 series servers):

• Oracle VM Server for SPARC 3.5, 3.5.0.1, and 3.5.0.2 releases

Notes:

1. No other SPARC servers are affected directly by this issue. However, a domain on another server that supports the 'migration-class1' value of the 'cpu-arch' property (at least the SPARC T4, SPARC M5, or SPARC S7 series server) becomes vulnerable if that domain is migrated to a SPARC M8 or a SPARC T8 series server.

2. To determine whether a guest domain is vulnerable to this issue, run the following command on the primary domain for each guest domain:

      # ldm list -l <guest-domain> | grep cpu-arch

A guest domain is vulnerable to this issue if the output shows 'cpu-arch=migration-class1'.

Symptoms

While the symptoms can vary, the Oracle Solaris kernel typically panics in the guest domain that has the 'cpu-arch=migration-class1' setting. The associated panic string is "bad unexpected error from hypervisor call at TL 1."

Workaround

Until an update is available, change the value of the 'cpu-arch' property on all SPARC M8 and SPARC T8 series servers as follows:

• For a guest domain that you do not plan to live migrate or you plan to live migrate to another SPARC M8 or SPARC T8 series server, set 'cpu-arch=native'.
• For a guest domain that you plan to live migrate to or from an older generation SPARC server, set 'cpu-arch=generic'.

Note: After setting the 'cpu-arch' property, you must reboot the guest domain to make the change take effect.

Resolution

A pending update to Oracle VM Server for SPARC software will remove 2 GB page size support from the 'migration-class1' CPU architecture type. This resolution will ensure that page size support is fully compatible for all supported SPARC platforms starting with the SPARC T4, SPARC M5, and SPARC S7 series servers. For more information about the 'cpu-arch' property, see:

https://docs.oracle.com/cd/E80106_01/html/E80109/migratingactivedomain.html

Note: Although the Administration Guide (as referenced by the link above) does not list the SPARC M8 and SPARC T8 series servers as options under 'migration-class1', those servers are in fact included, and the references in this Alert are applicable.

History

23-May-2018: Document released, status is Workaround

Questions regarding any portion of this document should be
addressed to sunalertpublication_us_grp@oracle.com and
copy the submitter/responsible engineer listed below.

Internal Contributor/Submitter: john.falkenthal@oracle.com
Internal Eng Responsible Engineer: dawn.tse@oracle.com
Oracle Knowledge Analyst: david.mariotto@oracle.com
Internal Eng Business Unit Group: Corporate Architecture
Internal Associated SRs: 3-17394777041

References

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