Commit 1d6e31e3 authored by Yanan Wang's avatar Yanan Wang Committed by Dongxu Sun
Browse files

KVM:arm64:Add a module param to enable/disable pv_preempted dynamically 

virt inclusion
category: performance
bugzilla: https://gitee.com/openeuler/kernel/issues/IBNSBL



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

Pv_preempted can not ensure performance improvement in any scenario,
so add a module param to enable/disable pv_preempted dynamically if
we don't need it.

Signed-off-by: default avatarYanan Wang <wangyanan55@huawei.com>
Signed-off-by: default avatarDongxu Sun <sundongxu3@huawei.com>
parent 0f19fd14

arch/arm64/include/asm/kvm_host.h

+4 −1
Original line number Diff line number Diff line
@@ -412,6 +412,7 @@ struct kvm_vcpu_arch { 
	/* Guest PV sched state */

	struct {

		bool pv_unhalted;

		bool preempted;

		gpa_t base;

	} pvsched;
@@ -645,12 +646,14 @@ long kvm_hypercall_pvsched_features(struct kvm_vcpu *vcpu); 
void kvm_update_pvsched_preempted(struct kvm_vcpu *vcpu, u32 preempted);

long kvm_pvsched_kick_vcpu(struct kvm_vcpu *vcpu);



extern bool pv_preempted_enable;

static inline void kvm_arm_pvsched_vcpu_init(struct kvm_vcpu_arch *vcpu_arch)

{

	vcpu_arch->pvsched.base = GPA_INVALID;

	vcpu_arch->pvsched.preempted = false;

}



static inline bool kvm_arm_is_pvsched_enabled(struct kvm_vcpu_arch *vcpu_arch)

static inline bool kvm_arm_is_pvsched_valid(struct kvm_vcpu_arch *vcpu_arch)

{

	return (vcpu_arch->pvsched.base != GPA_INVALID);

}

arch/arm64/kvm/arm.c

+24 −3
Original line number Diff line number Diff line
@@ -84,6 +84,15 @@ unsigned int twedel = 0; 
module_param(twedel, uint, S_IRUGO | S_IWUSR);

#endif



static const struct kernel_param_ops pv_preempted_enable_ops = {

	.set = param_set_bool,

	.get = param_get_bool,

};



bool pv_preempted_enable = true;

MODULE_PARM_DESC(pv_preempted_enable, "bool");

module_param_cb(pv_preempted_enable, &pv_preempted_enable_ops, &pv_preempted_enable, 0644);



static int vcpu_req_reload_wfi_traps(const char *val, const struct kernel_param *kp);



static const struct kernel_param_ops force_wfi_trap_ops = {
@@ -575,8 +584,20 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
	if (vcpu_has_ptrauth(vcpu))

		vcpu_ptrauth_disable(vcpu);



	if (kvm_arm_is_pvsched_enabled(&vcpu->arch))

	/*

	 * When pv_preempted is changed from enabled to disabled, preempted

	 * state will not be updated in kvm_arch_vcpu_put/load. So we must

	 * update the preempted state to 0 for every vCPU in case some vCPUs'

	 * preempted state will always be 1.

	 */

	if (kvm_arm_is_pvsched_valid(&vcpu->arch)) {

		if (pv_preempted_enable)

			kvm_update_pvsched_preempted(vcpu, 0);

		else {

			if (vcpu->arch.pvsched.preempted)

				kvm_update_pvsched_preempted(vcpu, 0);

		}

	}



#ifdef CONFIG_KVM_HISI_VIRT

	kvm_hisi_dvmbm_load(vcpu);
@@ -600,7 +621,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) 


	vcpu->cpu = -1;



	if (kvm_arm_is_pvsched_enabled(&vcpu->arch))

	if (kvm_arm_is_pvsched_valid(&vcpu->arch) && pv_preempted_enable)

		kvm_update_pvsched_preempted(vcpu, 1);



#ifdef CONFIG_KVM_HISI_VIRT

arch/arm64/kvm/pvsched.c

+2 −0
Original line number Diff line number Diff line
@@ -34,6 +34,8 @@ void kvm_update_pvsched_preempted(struct kvm_vcpu *vcpu, u32 preempted) 
	srcu_read_unlock(&kvm->srcu, idx);



	pagefault_enable();



	vcpu->arch.pvsched.preempted = !!preempted;

}



long kvm_pvsched_kick_vcpu(struct kvm_vcpu *vcpu)