IBM s390 Continues Working On Spectre Defense With Linux 4.17, VirtIO GPU Emulation

With the Linux 4.17 kernel the s390 architecture updates include more mitigation work around the Spectre Variant One and Two vulnerabilities.

The latest Spectre defensive measures for the IBM s390 architecture include consolidating the Spectre-related s390 code, automatic enabling/disabling of Spectre Variant Two for Expolines and Nobp methods, system log messages now when Spectre Variant Two is enabled, and enabling the CPU vulnerabilities option and attribute functions for reporting of Spectre V1 and V2 state. So it's mostly cleaning up and organizing of the Spectre code for s390 and ensuring the user is informed about the state of their hardware.

Other s390 work for Linux 4.17 includes support for persistent configuration data via the SCLP Store Data interface, VirtIO GPU emulation support in QEMU, support for Format-3 channel path descriptors, and various other bug fixes and improvements.

More details on the s390 work for the Linux 4.17 kernel cycle can be found via this pull request.