KVM: arm64: Add interface to support vCPU preempted check

euleros inclusion
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=35
CVE: NA

--------------------------------

This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself.
Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It
takes the CPU as parameter and return true if the CPU is preempted.
Then kernel can break the spin loops upon the retval of vcpu_is_preempted.

As kernel has used this interface, So lets support it.
Signed-off-by: NZengruan Ye <yezengruan@huawei.com>
Reviewed-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NChaochao Xing <xingchaochao@huawei.com>
Reviewed-by: NZengruan Ye <yezengruan@huawei.com>
Reviewed-by: NXiangyou Xie <xiexiangyou@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

arch/arm64/include/asm/paravirt.h

@@ -10,12 +10,29 @@ extern struct static_key paravirt_steal_rq_enabled;
 struct pv_time_ops {
 	unsigned long long (*steal_clock)(int cpu);
 };
+
+struct pv_sched_ops {
+	bool (*vcpu_is_preempted)(int cpu);
+};
+
+struct paravirt_patch_template {
+	struct pv_sched_ops sched;
+};
+
 extern struct pv_time_ops pv_time_ops;
+extern struct paravirt_patch_template pv_ops;
 
 static inline u64 paravirt_steal_clock(int cpu)
 {
 	return pv_time_ops.steal_clock(cpu);
 }
+
+__visible bool __native_vcpu_is_preempted(int cpu);
+static inline bool pv_vcpu_is_preempted(int cpu)
+{
+	return pv_ops.sched.vcpu_is_preempted(cpu);
+}
+
 #endif
 
 #endif

arch/arm64/include/asm/spinlock.h

@@ -18,6 +18,7 @@
 
 #include <asm/qrwlock.h>
 #include <asm/qspinlock.h>
+#include <asm/paravirt.h>
 
 /* See include/linux/spinlock.h */
 #define smp_mb__after_spinlock()	smp_mb()
@@ -30,9 +31,18 @@
  * https://lore.kernel.org/lkml/20200110100612.GC2827@hirez.programming.kicks-ass.net
  */
 #define vcpu_is_preempted vcpu_is_preempted
+#ifdef CONFIG_PARAVIRT
+static inline bool vcpu_is_preempted(int cpu)
+{
+	return pv_vcpu_is_preempted(cpu);
+}
+
+#else
+
 static inline bool vcpu_is_preempted(int cpu)
 {
 	return false;
 }
+#endif /* CONFIG_PARAVIRT */
 
 #endif /* __ASM_SPINLOCK_H */

arch/arm64/kernel/Makefile

@@ -51,7 +51,7 @@ arm64-obj-$(CONFIG_ACPI)		+= acpi.o
 arm64-obj-$(CONFIG_ARM64_ERR_RECOV)	+= ras.o
 arm64-obj-$(CONFIG_ACPI_NUMA)		+= acpi_numa.o
 arm64-obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL)	+= acpi_parking_protocol.o
-arm64-obj-$(CONFIG_PARAVIRT)		+= paravirt.o
+arm64-obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt-spinlocks.o
 arm64-obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
 arm64-obj-$(CONFIG_HIBERNATION)		+= hibernate.o hibernate-asm.o
 arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\

arch/arm64/kernel/paravirt-spinlocks.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ * Author: Zengruan Ye <yezengruan@huawei.com>
+ */
+
+#include <linux/spinlock.h>
+#include <asm/paravirt.h>
+
+__visible bool __native_vcpu_is_preempted(int cpu)
+{
+	return false;
+}

arch/arm64/kernel/paravirt.c

@@ -22,4 +22,9 @@ struct static_key paravirt_steal_enabled;
 struct static_key paravirt_steal_rq_enabled;
 
 struct pv_time_ops pv_time_ops;
+struct paravirt_patch_template pv_ops = {
+	.sched.vcpu_is_preempted		= __native_vcpu_is_preempted,
+};
+
 EXPORT_SYMBOL_GPL(pv_time_ops);
+EXPORT_SYMBOL_GPL(pv_ops);