linux-kernel - [PATCH 4/9] cpuidle-haltpoll: define arch_haltpoll

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Message-Id: <20240430183730.561960-5-ankur.a.arora@oracle.com>
Date: Tue, 30 Apr 2024 11:37:25 -0700
From: Ankur Arora <ankur.a.arora@...cle.com>
To: linux-pm@...r.kernel.org, kvm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: 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, peterz@...radead.org,
        arnd@...db.de, lenb@...nel.org, mark.rutland@....com,
        harisokn@...zon.com, joao.m.martins@...cle.com,
        boris.ostrovsky@...cle.com, konrad.wilk@...cle.com,
        ankur.a.arora@...cle.com
Subject: [PATCH 4/9] cpuidle-haltpoll: define arch_haltpoll_supported()

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

Right now kvm_para_has_hint(KVM_HINTS_REALTIME) is x86 only. In
pursuit of making cpuidle-haltpoll architecture independent, define
arch_haltpoll_supported() which handles the architectural check for
enabling haltpoll.

Move the (kvm_para_available() && kvm_para_has_hint(KVM_HINTS_REALTIME))
check to the x86 specific arch_haltpoll_supported().

Signed-off-by: Joao Martins <joao.m.martins@...cle.com>
Signed-off-by: Mihai Carabas <mihai.carabas@...cle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>

---
Changelog:

  - s/arch_haltpoll_want/arch_haltpoll_supported/
  - change the check in haltpoll_want() from:
      (kvm_para_available() && arch_haltpoll_want()) || force;
    to
      arch_haltpoll_supported() || force;

Dropped Rafael's acked-by due to these changes.

---
 arch/x86/include/asm/cpuidle_haltpoll.h |  1 +
 arch/x86/kernel/kvm.c                   | 10 ++++++++++
 drivers/cpuidle/cpuidle-haltpoll.c      |  9 ++-------
 include/linux/cpuidle_haltpoll.h        |  5 +++++
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
index c8b39c6716ff..43ce79b88662 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_supported(void);
 
 #endif
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 7f0732bc0ccd..e4dcbe9acc07 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -1151,4 +1151,14 @@ 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_supported(void)
+{
+	/* Do not load haltpoll if idle= is passed */
+	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
+		return false;
+
+	return kvm_para_available() && kvm_para_has_hint(KVM_HINTS_REALTIME);
+}
+EXPORT_SYMBOL_GPL(arch_haltpoll_supported);
 #endif
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index d8515d5c0853..70f585383171 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -15,7 +15,6 @@
 #include <linux/cpuidle.h>
 #include <linux/module.h>
 #include <linux/sched/idle.h>
-#include <linux/kvm_para.h>
 #include <linux/cpuidle_haltpoll.h>
 
 static bool force __read_mostly;
@@ -95,7 +94,7 @@ static void haltpoll_uninit(void)
 
 static bool haltpoll_want(void)
 {
-	return kvm_para_has_hint(KVM_HINTS_REALTIME) || force;
+	return arch_haltpoll_supported() || force;
 }
 
 static int __init haltpoll_init(void)
@@ -103,11 +102,7 @@ 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..a3caf01d3f0e 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_supported(void)
+{
+	return false;
+}
 #endif
 #endif
-- 
2.39.3