Intel explained its approach in its technical note about Spectre mitigation (“Speculative Execution Side Channel Mitigations“), the tech giant addressed the issue with an opt-in flag dubbed IBRS_ALL bit (IBRS states for Indirect Branch Restricted Speculation).
The Indirect Branch Restricted Speculation, along with Single Thread Indirect Branch Predictors (STIBP) and Indirect Branch Predictor Barrier (IBPB), prevent the abuse of the prediction feature and the exploitation of the flaw.
Torvalds speculate the Intel’s decision to address the issues in this way is mainly motivated by the intention to avoid legal liability. Recalling two decades of flawed chips would have a catastrophic impact on the tech giant.
Torvalds explained that the impact of using IBRS on existing hardware is so severe that no one will set the hardware capability bits.
Intel recommended OEMs, cloud service providers, system manufacturers, software vendors as well as end users to stop deploying the current versions of Spectre/Meltdown patches. The company announced to have found the root cause of reboot issued for Broadwell and Haswell platforms and is asking to wait for a fix.
The tech giant began rolling out to industry partners a beta update to address the issue.
“As we start the week, I want to provide an update on the reboot issues we reported Jan. 11. We have now identified the root cause for Broadwell and Haswell platforms, and made good progress in developing a solution to address it.”Intel said in a press release published on Monday. “Over the weekend, we began rolling out an early version of the updated solution to industry partners for testing, and we will make a final release available once that testing has been completed.”
Let’s hope Intel will release new Spectre/Meltdown patches soon
(Security Affairs – Spectre/Meltdown patches, Intel)