linux-kernel - [PATCH v4 2/8] x86/kvm: Move haltpoll

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Date: Thu, 15 Feb 2024 09:41:44 +0200
From: Mihai Carabas <mihai.carabas@...cle.com>
To: linux-arm-kernel@...ts.infradead.org
Cc: kvm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, catalin.marinas@....com, will@...nel.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, pbonzini@...hat.com, wanpengli@...cent.com,
        vkuznets@...hat.com, rafael@...nel.org, daniel.lezcano@...aro.org,
        akpm@...ux-foundation.org, pmladek@...e.com, peterz@...radead.org,
        dianders@...omium.org, npiggin@...il.com, rick.p.edgecombe@...el.com,
        joao.m.martins@...cle.com, juerg.haefliger@...onical.com,
        mic@...ikod.net, mihai.carabas@...cle.com, arnd@...db.de,
        ankur.a.arora@...cle.com
Subject: [PATCH v4 2/8] x86/kvm: Move haltpoll_want() to be arch defined

From: Joao Martins <joao.m.martins@...cle.com>

Right now, kvm_para_has_hint(KVM_HINTS_REALTIME) is x86 only, and so in the
pursuit of making cpuidle-haltpoll arch independent, move the check for
haltpoll enablement to be defined per architecture. Same thing for
boot_option_idle_override. To that end, add a arch_haltpoll_want() and move the
check there.

Signed-off-by: Joao Martins <joao.m.martins@...cle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>
Signed-off-by: Mihai Carabas <mihai.carabas@...cle.com>
Acked-by: Rafael J. Wysocki <rafael@...nel.org>
---
 arch/x86/include/asm/cpuidle_haltpoll.h |  1 +
 arch/x86/kernel/kvm.c                   | 10 ++++++++++
 drivers/cpuidle/cpuidle-haltpoll.c      |  8 ++------
 include/linux/cpuidle_haltpoll.h        |  5 +++++
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
index c8b39c6716ff..2c5a53ce266f 100644
--- a/arch/x86/include/asm/cpuidle_haltpoll.h
+++ b/arch/x86/include/asm/cpuidle_haltpoll.h
@@ -4,5 +4,6 @@
 
 void arch_haltpoll_enable(unsigned int cpu);
 void arch_haltpoll_disable(unsigned int cpu);
+bool arch_haltpoll_want(void);
 
 #endif
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 428ee74002e1..259212eb478d 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -1150,4 +1150,14 @@ void arch_haltpoll_disable(unsigned int cpu)
 	smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
+
+bool arch_haltpoll_want(void)
+{
+	/* Do not load haltpoll if idle= is passed */
+	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
+		return false;
+
+	return kvm_para_has_hint(KVM_HINTS_REALTIME);
+}
+EXPORT_SYMBOL_GPL(arch_haltpoll_want);
 #endif
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index d8515d5c0853..d68550270802 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -95,7 +95,7 @@ static void haltpoll_uninit(void)
 
 static bool haltpoll_want(void)
 {
-	return kvm_para_has_hint(KVM_HINTS_REALTIME) || force;
+	return (kvm_para_available() && arch_haltpoll_want()) || force;
 }
 
 static int __init haltpoll_init(void)
@@ -103,11 +103,7 @@ static int __init haltpoll_init(void)
 	int ret;
 	struct cpuidle_driver *drv = &haltpoll_driver;
 
-	/* Do not load haltpoll if idle= is passed */
-	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
-		return -ENODEV;
-
-	if (!kvm_para_available() || !haltpoll_want())
+	if (!haltpoll_want())
 		return -ENODEV;
 
 	cpuidle_poll_state_init(drv);
diff --git a/include/linux/cpuidle_haltpoll.h b/include/linux/cpuidle_haltpoll.h
index d50c1e0411a2..bae68a6603e3 100644
--- a/include/linux/cpuidle_haltpoll.h
+++ b/include/linux/cpuidle_haltpoll.h
@@ -12,5 +12,10 @@ static inline void arch_haltpoll_enable(unsigned int cpu)
 static inline void arch_haltpoll_disable(unsigned int cpu)
 {
 }
+
+static inline bool arch_haltpoll_want(void)
+{
+	return false;
+}
 #endif
 #endif
-- 
1.8.3.1