Messages in this thread Patch in this message |  | | From | Ashok Raj <> | Subject | [Part 2 v2[cleanup] 4/4] x86/microcode: Do not call apply_microde() on sibling threads | Date | Sat, 21 Jan 2023 13:35:12 -0800 |
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Microcode updates are applied at the core, and both threads of HT siblings will notice the update.
During late-load, after the primary has updated the microcode, it also reflects that in the per-cpu structure (cpuinfo_x86) holding the current revision.
Since the sibling hasn't had a chance to update the per-cpu revision, the current code calls apply_microcode() just as a way to verify and also update the per-cpu revision number.
But in the odd case when primary returned with an error, the secondary will try to perform a patchload and the primary has already been released to the system. This could be problematic.
Replace apply_microcode() with a call to collect_cpu_info() and let that call also update the per-cpu structure instead of returning the previously cached values.
Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: LKML <linux-kernel@vger.kernel.org> Cc: x86 <x86@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Alison Schofield <alison.schofield@intel.com> Cc: Reinette Chatre <reinette.chatre@intel.com> Cc: Thomas Gleixner (Intel) <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Stefan Talpalaru <stefantalpalaru@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Peter Zilstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Cooper <Andrew.Cooper3@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Martin Pohlack <mpohlack@amazon.de> --- arch/x86/kernel/cpu/microcode/core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 6ade3d59c404..089636b1643f 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -386,6 +386,7 @@ static int __wait_for_cpus(atomic_t *t, long long timeout) */ static int __reload_late(void *info) { + struct ucode_cpu_info *uci = ucode_cpu_info + cpu; int cpu = smp_processor_id(); enum ucode_state err; int ret = 0; @@ -422,12 +423,11 @@ static int __reload_late(void *info) /* * At least one thread has completed update on each core. - * For others, simply call the update to make sure the - * per-cpu cpuinfo can be updated with right microcode - * revision. + * For siblings, collect the cpuinfo and update the + * per-cpu cpuinfo with the current microcode revision. */ if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu) - err = microcode_ops->apply_microcode(cpu); + microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig); return ret; } -- 2.34.1
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