Created attachment 1591874 [details] output of step 7 above (flat text file) 1. Please describe the problem: Received this message at the end of boot: L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. System is FC 31 (x86_64 Rawhide) 2. What is the Version-Release number of the kernel: 5.3.0-0.rc0.git4.1.fc31.x86_64 3. Did it work previously in Fedora? If so, what kernel version did the issue *first* appear? Old kernels are available for download at https://koji.fedoraproject.org/koji/packageinfo?packageID=8 : This problem has come and gone for various kernels since fc 30 (rawhide)... 4. Can you reproduce this issue? If so, please provide the steps to reproduce the issue below: The only thing I do is boot this system 5. Does this problem occur with the latest Rawhide kernel? To install the Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by ``sudo dnf update --enablerepo=rawhide kernel``: 6. Are you running any modules that not shipped with directly Fedora's kernel?: Virtual Box 7. Please attach the kernel logs. You can get the complete kernel log for a boot with ``journalctl --no-hostname -k > dmesg.txt``. If the issue occurred on a previous boot, use the journalctl ``-b`` flag.
This is expected behaviour. Your CPU suffers from the L1TF bug described in CVE-2018-3646. The only guaranteed way to avoid data leakage between processes running on the same physical core is to disable SMT. The kernel is simply warning you of this.
Matthew, Thanks for the info. George...