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From: Dave Hansen <dave.hansen@intel.com>
To: Tony Battersby <tonyb@cybernetics.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Mario Limonciello <mario.limonciello@amd.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff
Date: Tue, 25 Apr 2023 13:03:22 -0700	[thread overview]
Message-ID: <f5c7a104-d422-bd02-d361-e9e9f433d41d@intel.com> (raw)
In-Reply-To: <3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com>

On 4/25/23 12:26, Tony Battersby wrote:
> -	if (cpuid_eax(0x8000001f) & BIT(0))
> +	if (c->extended_cpuid_level >= 0x8000001f &&
> +	    (cpuid_eax(0x8000001f) & BIT(0)))
>  		native_wbinvd();

Oh, so the existing code is running into the

> If a value entered for CPUID.EAX is higher than the maximum input
> value for basic or extended function for that processor then the data
> for the highest basic information leaf is returned
behavior.  It's basically looking at BIT(0) of some random extended
leaf.  Probably 0x80000008 based on your 'cpuid -r' output.



  parent reply	other threads:[~2023-04-25 20:03 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-25 19:26 [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff Tony Battersby
2023-04-25 19:39 ` Borislav Petkov
2023-04-25 19:58   ` Tony Battersby
2023-04-25 20:03 ` Dave Hansen [this message]
2023-04-25 20:34   ` Dave Hansen
2023-04-25 21:06     ` Borislav Petkov
2023-04-25 21:05   ` Thomas Gleixner
2023-04-25 22:29     ` Dave Hansen
2023-04-25 23:00       ` Thomas Gleixner
2023-04-26  0:10       ` H. Peter Anvin
2023-04-26 14:45     ` Tony Battersby
2023-04-26 16:37       ` Thomas Gleixner
2023-04-26 17:37         ` Tony Battersby
2023-04-26 17:41           ` [PATCH v2] x86/cpu: fix SME test in stop_this_cpu() Tony Battersby
2023-05-22 14:07             ` [PATCH v2 RESEND] " Tony Battersby
2023-04-26 17:51           ` [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff Tom Lendacky
2023-04-26 18:15             ` Dave Hansen
2023-04-26 19:18               ` Tom Lendacky
2023-04-26 22:02                 ` Andi Kleen
2023-04-26 23:20                   ` Thomas Gleixner
2023-04-26 20:00             ` Thomas Gleixner
2023-06-20 13:00 ` [tip: x86/core] x86/smp: Make stop_other_cpus() more robust tip-bot2 for Thomas Gleixner
2023-06-20 13:00 ` [tip: x86/core] x86/smp: Dont access non-existing CPUID leaf tip-bot2 for Tony Battersby

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