From: Josh Triplett <josh@joshtriplett.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Ashok Raj <ashok.raj@intel.com>,
Arjan van de Ven <arjan@linux.intel.com>,
Nikolay Borisov <nik.borisov@suse.com>
Subject: Re: [patch V2 02/37] x86/microcode: Hide the config knob
Date: Mon, 14 Aug 2023 16:57:30 -0700 [thread overview]
Message-ID: <ZNq/agLqraP0IYwR@localhost> (raw)
In-Reply-To: <20230814211912.GMZNqaUD6FriYo1wOo@fat_crate.local>
On Mon, Aug 14, 2023 at 11:19:12PM +0200, Borislav Petkov wrote:
> On Mon, Aug 14, 2023 at 02:01:03PM -0700, Josh Triplett wrote:
> > I'd be happy to help keep this case building. Would you consider
> > accepting a patch atop this series re-introducing minimal support for
> > disabling this?
>
> And a couple more KBs of builtin code is a problem because?
Multiple reasons. First, because "a couple more KBs" (concretely, 4637
bytes in this case) add up across the kernel. Second, because disabling
something is the easiest way to guarantee spending *zero* boot time on
it. And third, because I just confirmed that this requires a *trivial*
patch to support (apart from re-enabling the config option):
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -68,11 +68,12 @@ static inline u32 intel_get_microcode_revision(void)
return rev;
}
+#endif /* CONFIG_CPU_SUP_INTEL */
+#if defined(CONFIG_MICROCODE) && defined(CONFIG_CPU_SUP_INTEL)
void show_ucode_info_early(void);
-
-#else /* CONFIG_CPU_SUP_INTEL */
+#else
static inline void show_ucode_info_early(void) { }
-#endif /* !CONFIG_CPU_SUP_INTEL */
+#endif
#endif /* _ASM_X86_MICROCODE_H */
next prev parent reply other threads:[~2023-08-14 23:59 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-12 19:58 [patch V2 00/37] x86/microcode: Cleanup and late loading enhancements Thomas Gleixner
2023-08-12 19:58 ` [patch V2 01/37] x86/mm: Remove unused microcode.h include Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-12 19:58 ` [patch V2 02/37] x86/microcode: Hide the config knob Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-14 21:01 ` [patch V2 02/37] " Josh Triplett
2023-08-14 21:19 ` Borislav Petkov
2023-08-14 23:57 ` Josh Triplett [this message]
2023-08-15 8:25 ` Borislav Petkov
2023-08-12 19:58 ` [patch V2 03/37] x86/microcode/intel: Move microcode functions out of cpu/intel.c Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-23 12:51 ` [patch V2 03/37] " Qiuxu Zhuo
2023-08-23 17:46 ` Thomas Gleixner
2023-08-12 19:58 ` [patch V2 04/37] x86/microcode: Include vendor headers into microcode.h Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Ashok Raj
2023-08-12 19:58 ` [patch V2 05/37] x86/microcode: Make reload_early_microcode() static Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-12 19:58 ` [patch V2 06/37] x86/microcode/intel: Rename get_datasize() since its used externally Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Ashok Raj
2023-08-12 19:58 ` [patch V2 07/37] x86/microcode: Move core specific defines to local header Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-12 19:58 ` [patch V2 08/37] x86/microcode/intel: Remove debug code Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-12 19:58 ` [patch V2 09/37] x86/microcode/intel: Remove pointless mutex Thomas Gleixner
2023-08-13 6:55 ` Nikolay Borisov
2023-08-13 9:08 ` Thomas Gleixner
2023-08-13 17:26 ` [tip: x86/microcode] " tip-bot2 for Thomas Gleixner
2023-08-12 19:58 ` [patch V2 10/37] x86/microcode/intel: Rip out mixed stepping support for Intel CPUs Thomas Gleixner
2023-08-12 19:58 ` [patch V2 11/37] x86/microcode/intel: Simplify scan_microcode() Thomas Gleixner
2023-08-12 19:58 ` [patch V2 12/37] x86/microcode/intel: Simplify and rename generic_load_microcode() Thomas Gleixner
2023-08-14 13:19 ` Borislav Petkov
2023-08-14 14:40 ` Thomas Gleixner
2023-08-12 19:58 ` [patch V2 13/37] x86/microcode/intel: Cleanup code further Thomas Gleixner
2023-08-12 19:58 ` [patch V2 14/37] x86/microcode/intel: Simplify early loading Thomas Gleixner
2023-08-12 19:58 ` [patch V2 15/37] x86/microcode/intel: Save the microcode only after a successful late-load Thomas Gleixner
2023-08-12 19:59 ` [patch V2 16/37] x86/microcode/intel: Switch to kvmalloc() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 17/37] x86/microcode/intel: Unify microcode apply() functions Thomas Gleixner
2023-08-12 19:59 ` [patch V2 18/37] x86/microcode/intel: Rework intel_cpu_collect_info() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 19/37] x86/microcode/intel: Reuse intel_cpu_collect_info() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 20/37] x86/microcode/intel: Rework intel_find_matching_signature() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 21/37] x86/microcode/amd: Read revision from hardware in collect_cpu_info_amd() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 22/37] x86/microcode: Remove pointless apply() invocation Thomas Gleixner
2023-08-12 19:59 ` [patch V2 23/37] x86/microcode: Get rid of the schedule work indirection Thomas Gleixner
2023-08-12 19:59 ` [patch V2 24/37] x86/microcode: Clean up mc_cpu_down_prep() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 25/37] x86/microcode: Handle "nosmt" correctly Thomas Gleixner
2023-08-12 19:59 ` [patch V2 26/37] x86/microcode: Clarify the late load logic Thomas Gleixner
2023-08-13 20:02 ` Nikolay Borisov
2023-08-12 19:59 ` [patch V2 27/37] x86/microcode: Sanitize __wait_for_cpus() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 28/37] x86/microcode: Add per CPU result state Thomas Gleixner
2023-08-12 19:59 ` [patch V2 29/37] x86/microcode: Add per CPU control field Thomas Gleixner
2023-08-12 19:59 ` [patch V2 30/37] x86/microcode: Provide new control functions Thomas Gleixner
2023-08-12 19:59 ` [patch V2 31/37] x86/microcode: Replace the all in one rendevouz handler Thomas Gleixner
2023-08-12 19:59 ` [patch V2 32/37] x86/microcode: Rendezvous and load in NMI Thomas Gleixner
2023-08-12 19:59 ` [patch V2 33/37] x86/microcode: Protect against instrumentation Thomas Gleixner
2023-08-12 19:59 ` [patch V2 34/37] x86/apic: Provide apic_force_nmi_on_cpu() Thomas Gleixner
2023-08-12 19:59 ` [patch V2 35/37] x86/microcode: Handle "offline" CPUs correctly Thomas Gleixner
2023-08-12 19:59 ` [patch V2 36/37] x86/microcode: Prepare for minimal revision check Thomas Gleixner
2023-08-12 19:59 ` [patch V2 37/37] x86/microcode/intel: Add a minimum required revision for late-loads Thomas Gleixner
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