Messages in this thread | | | Date | Mon, 12 Feb 2024 20:53:28 -0800 | From | Pawan Gupta <> | Subject | Re: [PATCH v2] x86/bugs: Default retbleed to =stuff when retpoline is enabled |
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On Mon, Feb 12, 2024 at 05:23:21PM -0800, Pawan Gupta wrote: > On Intel systems when retpoline mitigation is enabled for spectre-v2, > retbleed=auto does not enable RSB stuffing. This may make the system > vulnerable to retbleed. Retpoline is not the default mitigation when > IBRS is present, but in virtualized cases a VMM can hide IBRS from > guests, resulting in guest deploying retpoline by default. Even if IBRS > is enumerated, a user can still select spectre_v2=retpoline. > > As with other mitigations, mitigate retbleed by default. On Intel > systems when retpoline is enabled, and retbleed mitigation is set to > auto, enable Call Depth Tracking and RSB stuffing i.e. retbleed=stuff > mitigation. For AMD/Hygon auto mode already selects the appropriate > mitigation.
By mistake I sent this patch twice, please ignore the duplicate:
https://lore.kernel.org/lkml/20240213042453.6j01GG4kjjcdTev7AtniyPHPRNH3RFHNGgVJ5nIXho4@z/
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