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From: Thomas Gleixner <tglx@linutronix.de>
To: Ashok Raj <ashok_raj@linux.intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>, x86@kernel.org, Tom Lendacky
 <thomas.lendacky@amd.com>, Andrew Cooper <andrew.cooper3@citrix.com>,
 Arjan van de Ven <arjan@linux.intel.com>, Huang Rui <ray.huang@amd.com>,
 Juergen Gross <jgross@suse.com>, Dimitri Sivanich
 <dimitri.sivanich@hpe.com>, Sohil Mehta <sohil.mehta@intel.com>, K Prateek
 Nayak <kprateek.nayak@amd.com>, Kan Liang <kan.liang@linux.intel.com>,
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 Feng Tang <feng.tang@intel.com>, Andy Shevchenko <andy@infradead.org>,
 Michael Kelley <mhklinux@outlook.com>, "Peter Zijlstra (Intel)"
 <peterz@infradead.org>, Andy Shevchenko <andy.shevchenko@gmail.com>, Wei
 Liu <wei.liu@kernel.org>, Ashok Raj <ashok.raj@intel.com>
Subject: Re: [patch V2 01/22] x86/cpu/topology: Make the APIC mismatch
 warnings complete
In-Reply-To: <ZbIvis3zHeQLZerL@araj-dh-work.jf.intel.com>
References: <20240117124704.044462658@linutronix.de>
 <20240117124902.403342409@linutronix.de>
 <ZbIvis3zHeQLZerL@araj-dh-work.jf.intel.com>
Date: Mon, 12 Feb 2024 16:39:11 +0100
Message-ID: <87ttmdk7z4.ffs@tglx>
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On Thu, Jan 25 2024 at 01:53, Ashok Raj wrote:
> On Tue, Jan 23, 2024 at 02:10:04PM +0100, Thomas Gleixner wrote:
>> From: Thomas Gleixner <tglx@linutronix.de>
>> 
>> Detect all possible combinations of mismatch right in the CPUID evaluation
>> code.
>> 
>> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>> 
>> ---
>>  arch/x86/include/asm/apic.h           |    5 ++---
>>  arch/x86/kernel/cpu/common.c          |   15 ++-------------
>>  arch/x86/kernel/cpu/topology_common.c |   12 ++++++++++++
>>  3 files changed, 16 insertions(+), 16 deletions(-)
>
> [snip]
>
>> --- a/arch/x86/kernel/cpu/topology_common.c
>> +++ b/arch/x86/kernel/cpu/topology_common.c
>> @@ -177,6 +177,18 @@ void cpu_parse_topology(struct cpuinfo_x
>>  
>>  	parse_topology(&tscan, false);
>>  
>> +	if (IS_ENABLED(CONFIG_X86_LOCAL_APIC)) {
>> +		if (c->topo.initial_apicid != c->topo.apicid) {
>> +			pr_err(FW_BUG "CPU%4u: APIC ID mismatch. CPUID: 0x%04x APIC: 0x%04x\n",
>> +			       cpu, c->topo.initial_apicid, c->topo.apicid);
>> +		}
>> +
>> +		if (c->topo.apicid != cpuid_to_apicid[cpu]) {
>> +			pr_err(FW_BUG "CPU%4u: APIC ID mismatch. Firmware: 0x%04x APIC: 0x%04x\n",
>> +			       cpu, cpuid_to_apicid[cpu], c->topo.apicid);
>> +		}
>
> Should we consider tainting the kernel when there is any mismatch?

No strong opinion about that.