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SubjectRe: [PATCH v2] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts
On Thu, Jul 14, 2022 at 09:11:18PM -0300, Thadeu Lima de Souza Cascardo wrote:
>On Thu, Jul 14, 2022 at 04:15:35PM -0700, Pawan Gupta wrote:
>> IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at
>> every kernel entry/exit. On Enhanced IBRS parts setting
>> MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at
>> every kernel entry/exit incur unnecessary performance loss.
>>
>> When Enhanced IBRS feature is present, print a warning about this
>> unnecessary performance loss.
>>
>> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
>
>Reviewed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

Thanks for the review.

Pawan

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