Comment 0 for bug 1761372

== Comment: #0 - Satheesh Rajendran <email address hidden> - 2018-04-04 08:58:54 ==
---Problem Description---
backport needed for spectre/meltdown mitigation machine type qemu patches

Reason:
For mitigating spectre/meltdown cpu vulnerability, qemu implements the machine capabilities cfpc,sbbc,ibs, which are present in the current qemu, but the default values of it would be broken(no mitigation) even fixes in hw/fw/sw is available.

Qemu further introduces machine type variant pseries-2.12-sxxm which would set bydefault below capabilities without need of explicitly mentioning it, if mitigation is available in fw/sw. which is missing needs a backport.

kvm -M pseries,help 2>&1|egrep 'cap-cfpc|cap-sbbc|cap-ibs
pseries-bionic.cap-sbbc=string (Speculation Barrier Bounds Checking (broken, workaround, fixed)(null))
pseries-bionic.cap-cfpc=string (Cache Flush on Privilege Change (broken, workaround, fixed)(null))
pseries-bionic.cap-ibs=string (Indirect Branch Serialisation (broken, workaround, fixed)(null))

Upstream qemu Commits:

813f3cf655 ppc/spapr-caps: Define the pseries-2.12-sxxm machine type
c76c0d3090 ppc/spapr-caps: Convert cap-ibs to custom spapr-cap
aaf265ffde ppc/spapr-caps: Convert cap-sbbc to custom spapr-cap
f27aa81e72 ppc/spapr-caps: Convert cap-cfpc to custom spapr-cap
87175d1bc5 ppc/spapr-caps: Add support for custom spapr_capabilities
cb931c2108 target/ppc: Check mask when setting cap_ppc_safe_indirect_branch

Contact Information = <email address hidden>

---uname output---
4.15.0-14-generic #15-Ubuntu SMP Mon Apr 2 19:47:43 UTC 2018

Machine Type = power9 boston 2.2 (pvr 004e 1202)

---Debugger---
A debugger is not configured

Userspace tool common name: qemu-kvm 1:2.11+dfsg-1ubuntu5

The userspace tool has the following bit modes: both

Userspace rpm: qemu-kvm 1:2.11+dfsg-1ubuntu5

Userspace tool obtained from project website: na

*Additional Instructions for <email address hidden>:
-Attach ltrace and strace of userspace application.