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FAILED: patch "[PATCH] x86/topology: Fix multiple packages shown on a single-package" failed to apply to 5.10-stable tree

PATCH [email protected] 1 participant 1 message Oct 26, 2022

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The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

2b12a7a126d6 ("x86/topology: Fix multiple packages shown on a single-package system") cb09a379724d ("x86/topology: Set cpu_die_id only if DIE_TYPE found")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2b12a7a126d62bdbd81f4923c21bf6e9a7fbd069 Mon Sep 17 00:00:00 2001
From: Zhang Rui <[email protected]>
Date: Fri, 14 Oct 2022 17:01:46 +0800
Subject: [PATCH] x86/topology: Fix multiple packages shown on a single-package
system

CPUID.1F/B does not enumerate Package level explicitly, instead, all the APIC-ID bits above the enumerated levels are assumed to be package ID bits.

Current code gets package ID by shifting out all the APIC-ID bits that Linux supports, rather than shifting out all the APIC-ID bits that CPUID.1F enumerates. This introduces problems when CPUID.1F enumerates a level that Linux does not support.

For example, on a single package AlderLake-N, there are 2 Ecore Modules with 4 atom cores in each module. Linux does not support the Module level and interprets the Module ID bits as package ID and erroneously reports a multi module system as a multi-package system.

Fix this by using APIC-ID bits above all the CPUID.1F enumerated levels as package ID.

[ dhansen: spelling fix ]

Fixes 7745f03eb395 ("x86/topology: Add CPUID.1F multi-die/package support")
Suggested-by Len Brown <[email protected]>
Signed-off-by Zhang Rui <[email protected]>
Signed-off-by Dave Hansen <[email protected]>
Reviewed-by Len Brown <[email protected]>
Cc [email protected]
Link https://lkml.kernel.org/r/[email protected] open here
arch/x86/kernel/cpu/topology.c +10 -4
index 132a2de44d2f..f7592814e5d5 100644
@@ -96,6 +96,7 @@ int detect_extended_topology(struct cpuinfo_x86 *c)
 	unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width;
 	unsigned int core_select_mask, core_level_siblings;
 	unsigned int die_select_mask, die_level_siblings;
+	unsigned int pkg_mask_width;
 	bool die_level_present = false;
 	int leaf;
 

@@ -111,10 +112,10 @@ int detect_extended_topology(struct cpuinfo_x86 *c)
 	core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
 	core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
 	die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
-	die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+	pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
 
 	sub_index = 1;
-	do {
+	while (true) {
 		cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
 
 		/*

@@ -132,8 +133,13 @@ int detect_extended_topology(struct cpuinfo_x86 *c)
 			die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
 		}
 
+		if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE)
+			pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+		else
+			break;
+
 		sub_index++;
-	} while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);
+	}
 
 	core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
 	die_select_mask = (~(-1 << die_plus_mask_width)) >>

@@ -148,7 +154,7 @@ int detect_extended_topology(struct cpuinfo_x86 *c)
 	}
 
 	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
-				die_plus_mask_width);
+				pkg_mask_width);
 	/*
 	 * Reinit the apicid, now that we have extended initial_apicid.
 	 */