APPLIED: [PATCH 0/2][B] Enhanced IBRS (LP: #1786139)

Stefan Bader stefan.bader at
Thu Nov 8 12:11:32 UTC 2018

On 20.10.18 01:34, Tyler Hicks wrote:
> BugLink:
> [Impact]
> Future Intel CPU's like Cascade Lake and GLK+ support Enhanced IBRS. Enhanced
> IBRS is a H/W mitigation technique for Spectre V2 bug. So, it's important to
> make sure that all the OSV's are using this feature.
> [Test Case]
> For processors that don't support Enhanced IBRS, the test is to ensure that
> /sys/devices/system/cpu/vulnerabilities/spectre_v2 doesn't change state after
> applying the patches. This will typically be the string when running on Intel
> processors that don't support Enhanced IBRS:
>   "Mitigation: Full generic retpoline, IBPB, IBRS_FW"
> New Intel processors that do support Enhanced IBRS will display "Enhanced IBRS"
> in place of "Full generic retpoline"
> [Regression Potential]
> Pretty low. The patches are fairly simple and they should only affect new
> processors. The main concern is around the possibility of regressing IBRS
> support on processors that don't support Enhanced IBRS.
> Tyler
Applied to bionic/master-next. Thanks.


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