Messages in this thread | | | Date | Thu, 9 Nov 2023 14:43:56 -0800 | From | Josh Poimboeuf <> | Subject | Re: [PATCH v5 12/12] x86/bugs: Add a separate config for missing mitigation |
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On Thu, Oct 26, 2023 at 10:09:17AM -0700, Breno Leitao wrote: > Hello Josh, > > On Wed, Oct 25, 2023 at 09:29:06AM -0700, Josh Poimboeuf wrote: > > On Thu, Oct 19, 2023 at 11:11:58AM -0700, Breno Leitao wrote: > > > Currently, the CONFIG_SPECULATION_MITIGATIONS is halfway populated, > > > where some mitigations have entries in Kconfig, and they could be > > > modified, while others mitigations do not have Kconfig entries, and > > > could not be controlled at build time. > > > > > > Create an entry for each CPU mitigation under > > > CONFIG_SPECULATION_MITIGATIONS. This allow users to enable or disable > > > them at compilation time. > > > > > > Signed-off-by: Breno Leitao <leitao@debian.org> > > > > We also probably need a CONFIG_MITIGATION_MELTDOWN. > > Isn't Meltdown covered by the MITIGATION_PAGE_TABLE_ISOLATION Kconfig > entry? Would you mind clarifying what would be the difference between > CONFIG_MITIGATION_MELTDOWN and MITIGATION_PAGE_TABLE_ISOLATION, and why > do we want CONFIG_MITIGATION_MELTDOWN?
Ah yes, not sure how I missed that one.
> > > + cmd = IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2) ? SPECTRE_V2_CMD_AUTO : SPECTRE_V2_CMD_NONE; > > > if (cmdline_find_option_bool(boot_command_line, "nospectre_v2") || > > > cpu_mitigations_off()) > > > return SPECTRE_V2_CMD_NONE; > > > > I'm thinking CONFIG_MITIGATION_SPECTRE_V2 should also affect whether the spectre v2 user > > mitigation gets enabled. > > Makes sense, would something like this be enough?
Looks good to me.
While you're at it, for consistency can you add a cpu_mitigations_off() check to spectre_v2_parse_user_cmdline()?
-- Josh
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