Messages in this thread | | | Date | Wed, 3 Apr 2024 07:50:49 -0700 | From | Pawan Gupta <> | Subject | Re: [PATCH v3] x86/bugs: Default retbleed to =stuff when retpoline is enabled |
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On Wed, Apr 03, 2024 at 05:32:40PM +0300, Nikolay Borisov wrote: > > > On 3.04.24 г. 8:54 ч., 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. > > > > Reported-by: Alyssa Milburn <alyssa.milburn@intel.com> > > Cc: stable@kernel.org > > Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> > > Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Thanks.
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