Linux 4.18 Gets AMD Patches For Speculative Store Bypass / Spectre V4

Written by Michael Larabel in AMD on 10 June 2018 at 07:57 AM EDT. 5 Comments
Linux 4.17 landed the initial Spectre V4 mitigation as "Speculative Store Bypass Disable" (SSBD) while primarily focused on Intel CPUs and for Linux 4.18 the SSBD code has been updated for AMD processors.

The in-development Linux 4.18 kernel will receive the patches for making use of the SPEC_CTRL / VIRT_SPEC MSRs to be provided by future AMD CPUs / firmware updates. The AMD SSBD work done by Konrad Rzeszutek Wilk of Oracle was previously covered here. The AMD SSBD whitepaper can be read here.

The AMD speculative store bypass patches are the only Spectre/Meltdown patches in the x86 space currently queued up for Linux 4.18 via the x86/pti pull request. Granted, we could still see more Spectre/Meltdown improvements land for Linux 4.18 given that this work generally gets accepted outside of the merge window since it's a security issue.

Outside of the x86 space for Spectre there is also Spectre V4 SSBD for ARM64 and finally 32-bit ARM Spectre V1/V2 patches coming with Linux 4.18.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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