Re: [PATCH 15/14] x86/gds: Lock GDS mitigation when keylocker feature is present

Daniel Sneddon
2024-04-19T18:03:30Z

On 4/19/24 10:47, Pawan Gupta wrote:
> + u64 gds_lock = 0;
>
> switch (gds_mitigation) {
> case GDS_MITIGATION_OFF:
> @@ -769,6 +769,8 @@ void update_gds_msr(void)
> * the same state. Make sure the mitigation is enabled on all
> * CPUs.
> */
> + gds_lock = GDS_MITG_LOCKED;
Can't we just drop the new gds_lock var and set mcu_ctrl |= GDS_MITG_LOCKED here?
> + fallthrough;
> case GDS_MITIGATION_FULL:
> rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
> mcu_ctrl &= ~GDS_MITG_DIS;
> @@ -779,6 +781,7 @@ void update_gds_msr(void)
> return;
> }
>
> + mcu_ctrl |= gds_lock;
> wrmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);