Linux 6.15 Set To Include Better Handling For Intel P Or E Core Only Mitigations
- Reference: 0001533418
- News link: https://www.phoronix.com/news/Linux-6.15-P-E-Core-Mitigation
- Source link:
For a number of months Intel engineers have been working to [1]properly handle the CPU hybrid topology for determining vulnerabilities/mitigations rather than blanket applying mitigations (or not) across both sets of CPU cores even if only the P or E cores are vulnerable.
Intel's motivation for this is initially around the Register File Data Sampling (RFDS) vulnerability where only the E cores on Alder Lake and Raptor Lake are susceptible to the issue. The P cores are not and thus the patch series will properly handle this case of applying to the specific CPU type that's vulnerable. So now with Linux 6.15+ the P cores on Raptor Lake and Alder Lake CPUs would be properly [2]excluded . The patches add in the proper infrastructure and then this RFDS handling is the only use case for the moment.
These patches were queued up into [3]tip/tip.git's x86/cpu branch ahead of the Linux 6.15 merge window opening later in March. With the patches part of the x86/cpu TIP branch, they are expected to be submitted and merged for Linux 6.15 barring any last minute issues or objections from being raised.
[1] https://www.phoronix.com/news/Intel-Hybrid-Topology-Mitigate
[2] https://web.git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/cpu&id=8c7768105a84c16b9d71af2fa2d2c50ff3c80f4e
[3] https://web.git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/?h=x86/cpu
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