linux-kernel - [PATCH v2 11/38] x86/kvmclock: Setup kvmclock for secondary CPUs iff CONFIG

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Message-ID: <20250227021855.3257188-12-seanjc@google.com>
Date: Wed, 26 Feb 2025 18:18:27 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Sean Christopherson <seanjc@...gle.com>, Juergen Gross <jgross@...e.com>, 
	"K. Y. Srinivasan" <kys@...rosoft.com>, Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>, 
	Dexuan Cui <decui@...rosoft.com>, Ajay Kaher <ajay.kaher@...adcom.com>, 
	Jan Kiszka <jan.kiszka@...mens.com>, Andy Lutomirski <luto@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>, Daniel Lezcano <daniel.lezcano@...aro.org>, 
	John Stultz <jstultz@...gle.com>
Cc: linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev, 
	kvm@...r.kernel.org, virtualization@...ts.linux.dev, 
	linux-hyperv@...r.kernel.org, xen-devel@...ts.xenproject.org, 
	Tom Lendacky <thomas.lendacky@....com>, Nikunj A Dadhania <nikunj@....com>
Subject: [PATCH v2 11/38] x86/kvmclock: Setup kvmclock for secondary CPUs iff CONFIG_SMP=y

Gate kvmclock's secondary CPU code on CONFIG_SMP, not CONFIG_X86_LOCAL_APIC.
Originally, kvmclock piggybacked PV APIC ops to setup secondary CPUs.
When that wart was fixed by commit df156f90a0f9 ("x86: Introduce
x86_cpuinit.early_percpu_clock_init hook"), the dependency on a local APIC
got carried forward unnecessarily.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kernel/kvmclock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index b898b95a7d50..80d1a06609c8 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -186,7 +186,7 @@ static void kvm_restore_sched_clock_state(void)
 	kvm_register_clock("primary cpu clock, resume");
 }
 
-#ifdef CONFIG_X86_LOCAL_APIC
+#ifdef CONFIG_SMP
 static void kvm_setup_secondary_clock(void)
 {
 	kvm_register_clock("secondary cpu clock");
@@ -324,7 +324,7 @@ void __init kvmclock_init(void)
 
 	x86_platform.get_wallclock = kvm_get_wallclock;
 	x86_platform.set_wallclock = kvm_set_wallclock;
-#ifdef CONFIG_X86_LOCAL_APIC
+#ifdef CONFIG_SMP
 	x86_cpuinit.early_percpu_clock_init = kvm_setup_secondary_clock;
 #endif
 	x86_platform.save_sched_clock_state = kvm_save_sched_clock_state;
-- 
2.48.1.711.g2feabab25a-goog