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From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org,
	x86@kernel.org
Cc: Juergen Gross <jgross@suse.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH 1/2] x86/cpu: fix BSP detection when running as Xen PV guest
Date: Fri,  5 Apr 2024 14:34:33 +0200
Message-Id: <20240405123434.24822-2-jgross@suse.com>
In-Reply-To: <20240405123434.24822-1-jgross@suse.com>
References: <20240405123434.24822-1-jgross@suse.com>
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When booting as a Xen PV guest the boot processor isn't detected
correctly and the following message is shown:

  CPU topo: Boot CPU APIC ID not the first enumerated APIC ID: 0 > 1

Additionally this results in one CPU being ignored.

Fix that by calling the BSP detection logic when registering the boot
CPU's APIC, too.

Fixes: 5c5682b9f87a ("x86/cpu: Detect real BSP on crash kernels")
Signed-off-by: Juergen Gross <jgross@suse.com>
---
 arch/x86/kernel/cpu/topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index aaca8d235dc2..23c3db5e6396 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -255,7 +255,7 @@ void __init topology_register_boot_apic(u32 apic_id)
 	WARN_ON_ONCE(topo_info.boot_cpu_apic_id != BAD_APICID);
 
 	topo_info.boot_cpu_apic_id = apic_id;
-	topo_register_apic(apic_id, CPU_ACPIID_INVALID, true);
+	topology_register_apic(apic_id, CPU_ACPIID_INVALID, true);
 }
 
 /**
-- 
2.35.3