From: Ashok Raj <ashok.raj@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>
Cc: Ashok Raj <ashok.raj@intel.com>,
LKML <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
Ingo Molnar <mingo@kernel.org>, Tony Luck <tony.luck@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Alison Schofield <alison.schofield@intel.com>,
Reinette Chatre <reinette.chatre@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Stefan Talpalaru <stefantalpalaru@yahoo.com>,
David Woodhouse <dwmw2@infradead.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Jonathan Corbet <corbet@lwn.net>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Peter Zilstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Andrew Cooper <Andrew.Cooper3@citrix.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Martin Pohlack <mpohlack@amazon.de>
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 [thread overview]
Message-ID: <20230121213512.251578-5-ashok.raj@intel.com> (raw)
In-Reply-To: <20230121213512.251578-1-ashok.raj@intel.com>
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
next prev parent reply other threads:[~2023-01-21 21:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 17:29 [PATCH v1 Part2 0/5] Declare safe late loadable microcode Ashok Raj
2023-01-13 17:29 ` [PATCH v1 Part2 1/5] x86/microcode: Move late load warning to the same function that taints kernel Ashok Raj
2023-01-19 21:48 ` Thomas Gleixner
2023-01-19 22:05 ` Ashok Raj
2023-01-13 17:29 ` [PATCH v1 Part2 2/5] x86/microcode/intel: Add minimum required revision to microcode header Ashok Raj
2023-01-19 22:03 ` Thomas Gleixner
2023-01-19 22:34 ` Ashok Raj
2023-01-13 17:29 ` [PATCH v1 Part2 3/5] x86/microcode: Add a generic mechanism to declare support for minrev Ashok Raj
2023-01-20 0:15 ` Thomas Gleixner
2023-01-20 2:19 ` Ashok Raj
2023-01-21 21:35 ` [Part 2 v2[cleanup] 0/4] Some additional cleanups in microcode Ashok Raj
2023-01-21 21:35 ` [Part 2 v2[cleanup] 1/4] x86/microcode: Taint kernel only if microcode loading was successful Ashok Raj
2023-01-21 21:35 ` [Part 2 v2[cleanup] 2/4] x86/microcode: Report invalid writes to reload sysfs file Ashok Raj
2023-01-21 21:35 ` [Part 2 v2[cleanup] 3/4] x86/microcode/intel: Fix collect_cpu_info() to reflect current microcode Ashok Raj
2023-01-21 21:35 ` Ashok Raj [this message]
2023-01-22 3:36 ` [Part 2 v2[cleanup] 4/4] x86/microcode: Do not call apply_microde() on sibling threads Ashok Raj
2023-01-26 16:52 ` [Part 2 v2[cleanup] 0/4] Some additional cleanups in microcode Ashok Raj
2023-01-27 13:49 ` Borislav Petkov
2023-01-13 17:29 ` [PATCH v1 Part2 4/5] x86/microcode/intel: Drop wbinvd() from microcode loading Ashok Raj
2023-01-13 17:29 ` [PATCH v1 Part2 5/5] x86/microcode: Provide an option to override minrev enforcement Ashok Raj
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