Add a blocking notifier that triggers when the host sends a hint
change notification.
Suggested-by: Joao Martins <[email protected]>
Signed-off-by: Ankur Arora <[email protected]>
---
arch/x86/include/asm/kvm_para.h | 10 ++++++++++
arch/x86/kernel/kvm.c | 16 ++++++++++++++++
include/asm-generic/kvm_para.h | 8 ++++++++
3 files changed, 34 insertions(+)
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 5a7ca5639c2e..54c3c7a3225e 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -2,6 +2,7 @@
#ifndef _ASM_X86_KVM_PARA_H
#define _ASM_X86_KVM_PARA_H
+#include <linux/notifier.h>
#include <asm/processor.h>
#include <asm/alternative.h>
#include <uapi/asm/kvm_para.h>
@@ -96,6 +97,9 @@ extern void kvm_disable_steal_time(void);
void do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
void kvm_callback_vector(struct pt_regs *regs);
+void kvm_realtime_notifier_register(struct notifier_block *nb);
+void kvm_realtime_notifier_unregister(struct notifier_block *nb);
+
#ifdef CONFIG_PARAVIRT_SPINLOCKS
void __init kvm_spinlock_init(void);
#else /* !CONFIG_PARAVIRT_SPINLOCKS */
@@ -137,6 +141,14 @@ static inline void kvm_disable_steal_time(void)
{
return;
}
+
+static inline void kvm_realtime_notifier_register(struct notifier_block *nb)
+{
+}
+
+static inline void kvm_realtime_notifier_unregister(struct notifier_block *nb)
+{
+}
#endif
#endif /* _ASM_X86_KVM_PARA_H */
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 163b7a7ec5f9..35ba4a837027 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -951,6 +951,20 @@ void __init kvm_spinlock_init(void)
static inline bool kvm_pv_spinlock(void) { return false; }
#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+static BLOCKING_NOTIFIER_HEAD(realtime_notifier);
+
+void kvm_realtime_notifier_register(struct notifier_block *nb)
+{
+ blocking_notifier_chain_register(&realtime_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(kvm_realtime_notifier_register);
+
+void kvm_realtime_notifier_unregister(struct notifier_block *nb)
+{
+ blocking_notifier_chain_unregister(&realtime_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(kvm_realtime_notifier_unregister);
+
#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
static void kvm_disable_host_haltpoll(void *i)
@@ -1004,6 +1018,8 @@ void kvm_trigger_reprobe_cpuid(struct work_struct *work)
paravirt_runtime_patch(true);
mutex_unlock(&text_mutex);
+
+ blocking_notifier_call_chain(&realtime_notifier, 0, NULL);
}
static DECLARE_WORK(trigger_reprobe, kvm_trigger_reprobe_cpuid);
diff --git a/include/asm-generic/kvm_para.h b/include/asm-generic/kvm_para.h
index 4a575299ad62..d443531b49ac 100644
--- a/include/asm-generic/kvm_para.h
+++ b/include/asm-generic/kvm_para.h
@@ -33,4 +33,12 @@ static inline bool kvm_para_available(void)
return false;
}
+static inline void kvm_realtime_notifier_register(struct notifier_block *nb)
+{
+}
+
+static inline void kvm_realtime_notifier_unregister(struct notifier_block *nb)
+{
+}
+
#endif
--
2.20.1