Need Eager FPU
Historically x86 has used a lazy FPU that restores the FPU registers in the context a #NM handler based on when the FPU is first used after a context switch. It turns out that through speculative execution it is possible to read values out of the FPU before the #NM takes effect. An eager FPU restore defeats this side channel. See CVE-2018-3665.
Updated by Electric Monk over 3 years ago
- Status changed from New to Closed
commit 4c28a617e3922d92a58e813a5b955eb526b9c386 Author: Robert Mustacchi <email@example.com> Date: 2018-06-19T19:34:37.000Z 9598 Need Eager FPU Reviewed by: Jerry Jelinek <firstname.lastname@example.org> Reviewed by: Patrick Mooney <email@example.com> Reviewed by: Bryan Cantrill <firstname.lastname@example.org> Reviewed by: John Levon <email@example.com> Reviewed by: Toomas Soome <firstname.lastname@example.org> Approved by: Richard Lowe <email@example.com>