linux-kernel - Re: [patch V2 01/22] x86/cpu/topology: Make the APIC mismatch warnings complete

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Date: Thu, 25 Jan 2024 01:53:14 -0800
From: Ashok Raj <ashok_raj@...ux.intel.com>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
	Tom Lendacky <thomas.lendacky@....com>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Huang Rui <ray.huang@....com>, Juergen Gross <jgross@...e.com>,
	Dimitri Sivanich <dimitri.sivanich@....com>,
	Sohil Mehta <sohil.mehta@...el.com>,
	K Prateek Nayak <kprateek.nayak@....com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Zhang Rui <rui.zhang@...el.com>,
	"Paul E. McKenney" <paulmck@...nel.org>,
	Feng Tang <feng.tang@...el.com>,
	Andy Shevchenko <andy@...radead.org>,
	Michael Kelley <mhklinux@...look.com>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	Andy Shevchenko <andy.shevchenko@...il.com>,
	Wei Liu <wei.liu@...nel.org>, Ashok Raj <ashok.raj@...el.com>
Subject: Re: [patch V2 01/22] x86/cpu/topology: Make the APIC mismatch
 warnings complete

On Tue, Jan 23, 2024 at 02:10:04PM +0100, Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@...utronix.de>
> 
> Detect all possible combinations of mismatch right in the CPUID evaluation
> code.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.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?