From: Fenghua Yu <fenghua.yu@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, H Peter Anvin <hpa@zytor.com>,
Christopherson Sean J <sean.j.christopherson@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Radim Krcmar <rkrcmar@redhat.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v2 2/2] x86/cpufeatures: Enumerate new AVX512 BFLOAT16 instructions
Date: Thu, 20 Jun 2019 07:06:15 -0700 [thread overview]
Message-ID: <20190620140614.GA238683@romley-ivt3.sc.intel.com> (raw)
In-Reply-To: <20190620103720.GB28032@zn.tnic>
On Thu, Jun 20, 2019 at 12:37:20PM +0200, Borislav Petkov wrote:
> On Wed, Jun 19, 2019 at 02:34:04PM -0700, Fenghua Yu wrote:
> You need to test the sub-leaf index validity here before accessing
> subleaf 1:
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 4910cb421b82..dad20bc891d5 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -848,8 +848,11 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
> c->x86_capability[CPUID_7_ECX] = ecx;
> c->x86_capability[CPUID_7_EDX] = edx;
>
> - cpuid_count(0x00000007, 1, &eax, &ebx, &ecx, &edx);
> - c->x86_capability[CPUID_7_1_EAX] = eax;
> + /* Check valid sub-leaf index before accessing it */
> + if (eax >= 1) {
> + cpuid_count(0x00000007, 1, &eax, &ebx, &ecx, &edx);
> + c->x86_capability[CPUID_7_1_EAX] = eax;
> + }
You are right.
I tested the three patches in tip tree and they work as expected.
Thank you very much!
-Fenghua
next prev parent reply other threads:[~2019-06-20 14:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 18:00 [PATCH v2 0/2] x86/cpufeatures: Re-arrange a few features and enumerate AVX512 BFLOAT16 intructions Fenghua Yu
2019-06-17 18:00 ` [PATCH v2 1/2] x86/cpufeatures: Combine word 11 and 12 into new scattered features word 11 Fenghua Yu
2019-06-19 17:36 ` Borislav Petkov
2019-06-19 21:24 ` Fenghua Yu
2019-06-20 11:37 ` [tip:x86/cpu] x86/cpufeatures: Combine word 11 and 12 into a new scattered features word tip-bot for Fenghua Yu
2019-06-17 18:00 ` [PATCH v2 2/2] x86/cpufeatures: Enumerate new AVX512 BFLOAT16 instructions Fenghua Yu
2019-06-19 17:31 ` Borislav Petkov
2019-06-19 21:34 ` Fenghua Yu
2019-06-20 10:37 ` Borislav Petkov
2019-06-20 14:06 ` Fenghua Yu [this message]
2019-06-20 11:38 ` [tip:x86/cpu] x86/cpufeatures: Enumerate the " tip-bot for Fenghua Yu
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