Displaying 3 results from an estimated 3 matches for "ibrs_enabled".
2020 Jun 18
0
very low performance of Xen guests
..., spectre or something else.
>
>
I finally managed to install a fresh KVM host / guest pair on an
identical blade ( HS21XM, 64 GB ram, 2*E5450@ 3.00GHz ). Here are the
results I see:
1. KVM host, stock instalation and fully updated, kernel 3.10.0-1127.10.1
#cd /sys/kernel/debug/x86/
#cat ibrs_enabled pti_enabled retp_enabled
0
1
1
#time yum -y reinstall kernel-3.10.0-1127.el7.x86_64
real??? 0m50.026s
user??? 0m32.872s
sys???? 0m23.312s
2. KVM guest on the same machine (virt-install --name guest1-rhel7
--memory 2048 --vcpus 2? --disk size=20 --network=bridge:br0 --pxe
--os-variant rhel7 <...
2019 Jun 12
1
Speculative attack mitigations
..., speculative store bypass (ssbd), as well as MDS via MD_CLEAR mitigation.
When I mount the debugfs, the flag for ibrs is missing - preventing me enabling it as a mitigation for ssbd (due to lack of relevant cpu flag):
# mount -t debugfs none /sys/kernel/debug/
# ls -lahtr /sys/kernel/debug/x86/ibrs_enabled
ls: cannot access /sys/kernel/debug/x86/ibrs_enabled: No such file or directory
I have other R620's with the same CPUs running stock el6 kernels that are showing as fully patched to these issues. Could I please get some feedback from whoever builds out the kernels; if the mitigations/patche...
2020 Jun 14
4
very low performance of Xen guests
Hello
??? For the past months I've been testing upgrading my Xen hosts to
CentOS 7 and I face an issue for which I need your help to solve.
??? The testing machines are IBM blades, model H21 and H21XM. Initial
tests were performed on the H21 with 16 GB RAM; during the last 6=7
weeks I've been using the H21XM with 64 GB. In all cases the guests were
fully updated CentOS 7 --