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From: Thomas Gleixner <tglx@linutronix.de>
To: Lai Jiangshan <jiangshanlai@gmail.com>, linux-kernel@vger.kernel.org
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andi Kleen <ak@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Uros Bizjak <ubizjak@gmail.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	Juergen Gross <jgross@suse.com>, Joerg Roedel <jroedel@suse.de>,
	Jian Cai <caij2003@gmail.com>
Subject: Re: [PATCH 2/4] x86/entry: Use asm_noist_exc_nmi() for NMI in early booting stage
Date: Mon, 03 May 2021 22:24:18 +0200	[thread overview]
Message-ID: <878s4vk1l9.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <87bl9rk23k.ffs@nanos.tec.linutronix.de>

On Mon, May 03 2021 at 22:13, Thomas Gleixner wrote:

> On Tue, Apr 27 2021 at 07:09, Lai Jiangshan wrote:
>> + *
>> + * While the other entries for the exceptions which use Interrupt stacks can
>> + * be also used on the kernel stack, asm_exc_nmi() can not be used on the
>> + * kernel stack for it relies on the RSP-located "NMI executing" variable
>> + * which expects to on a fixed location in the NMI IST stack.  For early
>> + * booting stage, asm_noist_exc_nmi() is used for NMI.
>>   */
>>  static const __initconst struct idt_data def_idts[] = {
>>  	INTG(X86_TRAP_DE,		asm_exc_divide_error),
>> -	INTG(X86_TRAP_NMI,		asm_exc_nmi),
>> +	INTG(X86_TRAP_NMI,		asm_noist_exc_nmi),
>
> Actually this is a x86_64 only problem. The 32bit variant is fine, but
> for consistency there is no problem to have that extra entry point on
> 32bit as well.

Bah, no. This patch breaks 32bit because on 32bit nothing sets the entry
to asm_exc_nmi() later on.

Thanks,

        tglx

  reply	other threads:[~2021-05-03 20:24 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26 23:09 [PATCH 0/4] x86: Don't invoke asm_exc_nmi() on the kernel stack Lai Jiangshan
2021-04-26 23:09 ` [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi Lai Jiangshan
2021-04-28 21:27   ` Steven Rostedt
2021-04-30  7:15     ` Paolo Bonzini
2021-04-30 12:05       ` Steven Rostedt
2021-05-03 19:05   ` Thomas Gleixner
2021-05-03 19:41     ` Thomas Gleixner
2021-05-10  7:59   ` Juergen Gross
2021-04-26 23:09 ` [PATCH 2/4] x86/entry: Use asm_noist_exc_nmi() for NMI in early booting stage Lai Jiangshan
2021-04-28 21:30   ` Steven Rostedt
2021-05-03 20:13   ` Thomas Gleixner
2021-05-03 20:24     ` Thomas Gleixner [this message]
2021-05-03 21:45       ` Thomas Gleixner
2021-05-04 12:43         ` Thomas Gleixner
2021-05-04 19:50           ` [PATCH] KVM/VMX: Invoke NMI non-IST entry instead of IST entry Thomas Gleixner
2021-05-04 21:05             ` Maxim Levitsky
2021-05-04 21:12               ` Paolo Bonzini
2021-05-04 21:21                 ` Sean Christopherson
2021-05-04 21:23                   ` Andy Lutomirski
2021-05-04 21:25                     ` Paolo Bonzini
2021-05-04 21:51                       ` Sean Christopherson
2021-05-04 21:56                         ` Paolo Bonzini
2021-05-05  0:00                           ` Thomas Gleixner
2021-05-05 15:44                             ` Lai Jiangshan
2021-05-05  1:07                     ` Lai Jiangshan
2021-05-05  1:11                       ` Andy Lutomirski
2021-05-06 12:14             ` [tip: x86/urgent] " tip-bot2 for Lai Jiangshan
2021-04-26 23:09 ` [PATCH 3/4] " Lai Jiangshan
2021-04-30  2:46   ` Lai Jiangshan
2021-05-03 19:37   ` Thomas Gleixner
2021-05-03 20:02   ` Thomas Gleixner
2021-05-04  8:10     ` Paolo Bonzini
2021-04-26 23:09 ` [PATCH 4/4] KVM/VMX: Fold handle_interrupt_nmi_irqoff() into its solo caller Lai Jiangshan
2021-04-30  9:03   ` Thomas Gleixner
2021-04-30  9:06     ` Paolo Bonzini
2021-04-30 23:28       ` Thomas Gleixner
2021-04-30  7:14 ` [PATCH 0/4] x86: Don't invoke asm_exc_nmi() on the kernel stack Paolo Bonzini
2021-05-03 14:36   ` Thomas Gleixner

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