Messages in this thread | | | Date | Wed, 22 Jun 2022 13:48:44 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH 4.9 13/20] x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data |
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Hi!
> +static int __init mmio_stale_data_parse_cmdline(char *str) > +{ > + if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) > + return 0; > + > + if (!str) > + return -EINVAL; > + > + if (!strcmp(str, "off")) { > + mmio_mitigation = MMIO_MITIGATION_OFF; > + } else if (!strcmp(str, "full")) { > + mmio_mitigation = MMIO_MITIGATION_VERW; > + } else if (!strcmp(str, "full,nosmt")) { > + mmio_mitigation = MMIO_MITIGATION_VERW; > + mmio_nosmt = true; > + } > + > + return 0; > +}
This is wrong, AFAICT. Returning 0 will pollute init's environment; Randy was cleaning those lately and we are even seeing them in -stable. See for example b793a01000122d2bd133ba451a76cc135b5e162c.
The early return 0 should disappear, too; we should validate the option even on non-buggy machines.
Best regards, Pavel
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