Messages in this thread | | | Date | Thu, 28 Mar 2024 23:57:42 -0700 | From | Pawan Gupta <> | Subject | Re: [PATCH v9 10/14] x86/cpu/keylocker: Check Gather Data Sampling mitigation |
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On Thu, Mar 28, 2024 at 06:53:42PM -0700, Chang S. Bae wrote: > +/* > + * The mitigation is implemented at a microcode level. Ensure that the > + * microcode update is applied and the mitigation is locked. > + */ > +static bool __init have_gds_mitigation(void) > +{ > + u64 mcu_ctrl; > + > + /* GDS_CTRL is set if new microcode is loaded. */ > + if (!(x86_read_arch_cap_msr() & ARCH_CAP_GDS_CTRL)) > + goto vulnerable; > + > + /* If GDS_MITG_LOCKED is set, GDS_MITG_DIS is forced to 0. */ > + rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl); > + if (mcu_ctrl & GDS_MITG_LOCKED) > + return true;
Similar to RFDS, above checks can be simplified to:
if (gds_mitigation == GDS_MITIGATION_FULL_LOCKED) return true; > + > +vulnerable: > + pr_warn("x86/keylocker: Susceptible to the GDS vulnerability.\n"); > + return false; > +}
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