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From: "Ahmed S. Darwish" <darwi@linutronix.de>
To: 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>,
	"Ahmed S. Darwish" <darwi@linutronix.de>
Subject: [PATCH v1 08/12] tools/x86/kcpuid: Restrict CPUID scanning to valid vendor ranges
Date: Thu,  6 Mar 2025 21:49:56 +0100	[thread overview]
Message-ID: <20250306205000.227399-9-darwi@linutronix.de> (raw)
In-Reply-To: <20250306205000.227399-1-darwi@linutronix.de>

kcpuid works in two runs: one run for invoking the CPUID instructions and
saving all their output in memory, and another for parsing that raw
in-memory output using the CSV file specification.  In both runs, kcpuid
should only process CPUID ranges that are valid for the current CPU
vendor.

Restrict for_each_cpuid_range() to only iterate over CPUID ranges that
are known to be valid for this CPU vendor.  Doing it at the iterator
level avoids sprinkling ugly CPU-vendor CPUID range validity conditionals
throughout the code.  Overall, this allows adding vendor-specific CPUID
rages to the CSV file at later commits.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
---
 tools/arch/x86/kcpuid/kcpuid.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/arch/x86/kcpuid/kcpuid.c b/tools/arch/x86/kcpuid/kcpuid.c
index 36efcb753b77..3153c8eba0c4 100644
--- a/tools/arch/x86/kcpuid/kcpuid.c
+++ b/tools/arch/x86/kcpuid/kcpuid.c
@@ -118,7 +118,9 @@ static char *range_to_str(struct cpuid_range *range)
 
 #define for_each_cpuid_range(range)				\
 	for (unsigned int i = 0;				\
-	     i < ARRAY_SIZE(ranges) && ((range) = &ranges[i]);	\
+	     i < ARRAY_SIZE(ranges)		&&		\
+		     ((range) = &ranges[i])	&&		\
+		     (range->vendors & this_cpu_vendor);	\
 	     i++)
 
 struct cpuid_range *index_to_cpuid_range(u32 index)
-- 
2.48.1


  parent reply	other threads:[~2025-03-06 20:50 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
2025-03-10 14:21     ` Ahmed S. Darwish
2025-03-06 20:49 ` Ahmed S. Darwish [this message]
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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