Dear team My Guest os (CentOS 6.5 ,kernel version 2.6.32-696.18.7.el6.x86_64) is running in ESXI server (VMware ESXi 5.5.0 build-6480324, patch ESXi550-201709001.zip was applied ) . I installed all the packages mention in https://lists.centos.org/ pipermail/centos-announce/2018-January/ The list of installed packages are -> kernel-debug-devel-2.6.32-696.18.7.el6.i686 kernel-2.6.32-696.18.7.el6.x86_64 kernel-doc-2.6.32-696.18.7.el6.noarch kernel-debug-2.6.32-696.18.7.el6.x86_64 kernel-devel-2.6.32-696.18.7.el6.x86_64 kernel-debug-devel-2.6.32-696.18.7.el6.x86_64 libreport-plugin-kerneloops-2.0.9-19.el6.centos.x86_64 abrt-addon-kerneloops-2.0.8-21.el6.centos.x86_64 dracut-kernel-004-409.el6_8.2.noarch kernel-headers-2.6.32-696.18.7.el6.x86_64 kernel-firmware-2.6.32-696.18.7.el6.noarch kernel-abi-whitelists-2.6.32-696.18.7.el6.noarch dracut-004-409.el6_8.2.noarch dracut-kernel-004-409.el6_8.2.noarch elfutils-libs-0.164-2.el6.x86_64 elfutils-0.164-2.el6.x86_64 elfutils-libelf-devel-0.164-2.el6.x86_64 elfutils-libelf-0.164-2.el6.x86_64 elfutils-devel-0.164-2.el6.x86_64 microcode_ctl-1.17-25.2.el6_9.x86_64 python-perf-2.6.32-696.18.7.el6.x86_64 perf-2.6.32-696.18.7.el6.x86_64 *But /sys/kernel/debug/x86/ibrs_enabled is still set to 0 and if I execute "echo 2 > /sys/kernel/debug/x86/ibrs_enabled"* * then we are getting the error "bash: echo: write error: No such device" .* * The content of /sys/kernel/debug/x86/ibpb_enabled is also 0 and echo 1 > /sys/kernel/debug/x86/ibpb_enabled throws the* * error "bash: echo: write error: No such device" .* I used a tool https://raw.githubusercontent.com/speed47/spectre-meltdown- checker/master/spectre-meltdown-checker.sh to detect if meltdown and spectre got fixed . Spectre Variant 1 and Meltdown got fixed but not Variant 2 . "CVE-2017-5715 [branch target injection] aka 'Spectre Variant 2' * Mitigation 1 * Hardware (CPU microcode) support for mitigation: YES * Kernel support for IBRS: YES * IBRS enabled for Kernel space: NO * IBRS enabled for User space: NO * Mitigation 2 * Kernel compiled with retpoline option: NO * Kernel compiled with a retpoline-aware compiler: NO

STATUS: VULNERABLE (IBRS hardware + kernel support OR kernel with

retpoline are needed to mitigate the vulnerability)" Thanks in advance Thanks and regards AKSHAR