From: Dave Hansen <dave.hansen@intel.com>
To: "Ahmed S. Darwish" <darwi@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Andrew Cooper <andrew.cooper3@citrix.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, John Ogness <john.ogness@linutronix.de>,
x86-cpuid@lists.linux.dev, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 07/12] tools/x86/kcpuid: Add rudimentary CPU vendor detection
Date: Fri, 7 Mar 2025 07:03:43 -0800 [thread overview]
Message-ID: <0ade78e7-7a3c-459d-bf1c-f0bb1f24baee@intel.com> (raw)
In-Reply-To: <20250306205000.227399-8-darwi@linutronix.de>
On 3/6/25 12:49, Ahmed S. Darwish wrote:
> The kcpuid CSV file will soon be updated with CPUID indices that are only
> valid for certain CPU vendors, such as Centaur or Transmeta. Thus,
> introduce rudimentary x86 vendor detection to kcpuid.
Do we really need the vendor detection? For example, look at the end of
cpuid(1)'s output:
# cpuid -1 --raw
...
0x20000000 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000
edx=0x00000000
...
0x80860000 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000
edx=0x00000000
0xc0000000 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000
edx=0x00000000
It seems to just blindly poke at all of the CPUID regions. There are
only a handful of these and there's no hard in poking at them other
than an extra couple of executions of CPUID.
next prev parent reply other threads:[~2025-03-07 15:03 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-06 20:49 [PATCH v1 00/12] tools/x86/kcpuid: x86-cpuid-db v2.2 update Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 01/12] tools/x86/kcpuid: Fix error handling Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 02/12] tools/x86/kcpuid: Remove unused local variable Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 03/12] tools/x86/kcpuid: Remove unused global variable Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 04/12] tools/x86/kcpuid: Simplify usage() handling Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 05/12] tools/x86/kcpuid: Refactor CPUID range handling for future expansion Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 06/12] tools/x86/kcpuid: Extend CPUID index mask macro Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 07/12] tools/x86/kcpuid: Add rudimentary CPU vendor detection Ahmed S. Darwish
2025-03-06 21:07 ` Andrew Cooper
2025-03-07 14:06 ` Ahmed S. Darwish
2025-03-06 22:00 ` Dave Hansen
2025-03-07 13:48 ` Ahmed S. Darwish
2025-03-07 15:46 ` H. Peter Anvin
2025-03-07 15:03 ` Dave Hansen [this message]
2025-03-10 14:21 ` Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 08/12] tools/x86/kcpuid: Restrict CPUID scanning to valid vendor ranges Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 09/12] tools/x86/kcpuid: Define Transmeta and Centaur index ranges Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 10/12] tools/x86/kcpuid: Update bitfields to x86-cpuid-db v2.0 Ahmed S. Darwish
2025-03-07 3:18 ` H. Peter Anvin
2025-03-07 15:07 ` Ahmed S. Darwish
2025-03-07 15:27 ` H. Peter Anvin
2025-03-10 14:47 ` Ahmed S. Darwish
2025-03-06 20:49 ` [PATCH v1 11/12] tools/x86/kcpuid: Update bitfields to x86-cpuid-db v2.2 Ahmed S. Darwish
2025-03-06 20:50 ` [PATCH v1 12/12] MAINTAINERS: Include kcpuid under X86 CPUID DATABASE Ahmed S. Darwish
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