Commit 63042c58 authored by Zengruan Ye's avatar Zengruan Ye Committed by Zheng Zengkai
Browse files

KVM: arm64: Add interface to support vCPU preempted check 



virt inclusion
category: feature
bugzilla: 47624
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: default avatarZengruan Ye <yezengruan@huawei.com>
Reviewed-by: default avatarZhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 76732c97

arch/arm64/include/asm/paravirt.h

+11 −0
Original line number Diff line number Diff line
@@ -11,8 +11,13 @@ 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_time_ops time;

	struct pv_sched_ops sched;

};



extern struct paravirt_patch_template pv_ops;
@@ -24,6 +29,12 @@ static inline u64 paravirt_steal_clock(int cpu) 


int __init pv_time_init(void);



__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);

}



#else



#define pv_time_init() do {} while (0)

arch/arm64/include/asm/spinlock.h

+10 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 


#include <asm/qrwlock.h>

#include <asm/qspinlock.h>

#include <asm/paravirt.h>



/* See include/linux/spinlock.h */

#define smp_mb__after_spinlock()	smp_mb()
@@ -19,9 +20,18 @@ 
 * 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

+1 −1
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o 
obj-$(CONFIG_ACPI)			+= acpi.o

obj-$(CONFIG_ACPI_NUMA)			+= acpi_numa.o

obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL)	+= acpi_parking_protocol.o

obj-$(CONFIG_PARAVIRT)			+= paravirt.o

obj-$(CONFIG_PARAVIRT)			+= paravirt.o paravirt-spinlocks.o

obj-$(CONFIG_RANDOMIZE_BASE)		+= kaslr.o

obj-$(CONFIG_HIBERNATION)		+= hibernate.o hibernate-asm.o

obj-$(CONFIG_KEXEC_CORE)		+= machine_kexec.o relocate_kernel.o	\

arch/arm64/kernel/paravirt-spinlocks.c

0 → 100644
+13 −0
Original line number Diff line number Diff line 
// 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

+3 −1
Original line number Diff line number Diff line
@@ -26,7 +26,9 @@ 
struct static_key paravirt_steal_enabled;

struct static_key paravirt_steal_rq_enabled;



struct paravirt_patch_template pv_ops;

struct paravirt_patch_template pv_ops = {

	.sched.vcpu_is_preempted		= __native_vcpu_is_preempted,

};

EXPORT_SYMBOL_GPL(pv_ops);



struct pv_time_stolen_time_region {