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

Kleber Souza kleber.souza at canonical.com
Tue Nov 6 14:53:06 UTC 2018


On 10/20/18 01:34, Tyler Hicks wrote:
> BugLink: https://launchpad.net/bugs/1786139
>
> [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
>
>
Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>




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