Microsoft has released an update that disables Intel’s microcode Spectre mitigations.
Intel has reported issues with recently released microcode meant to address Spectre variant 2 (CVE 2017-5715 Branch Target Injection) – specifically Intel noted that this microcode can cause “higher than expected reboots and other unpredictable system behavior” and then noted that situations like this may result in “data loss or corruption”. Our own experience is that system instability can in some circumstances cause data loss or corruption. On January 22, Intel recommended that customers stop deploying the current microcode version on affected processors while they perform additional testing on the updated solution. We understand that Intel is continuing to investigate the potential effect of the current microcode version, and we encourage customers to review their guidance on an ongoing basis to inform their decisions.
This whole thing is a mess.
After being aware of the issue for 6 months, it seems now clear that either there is no microcode solution able to solve the problem, or the solution would compromise performances so much that Intel would have to pay back customers.
I’m afraid that Intel won’t really fix the issue in current chips, a bit like with the old Pentium FDIV bug, they will insist, at first, that it won’t be a real problem in most situations.