Commit 7c0e37ce authored by Zhiqiang Ni's avatar Zhiqiang Ni Committed by ni-zhiqiang111
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KVM:arm64:Add a kvm parameter to control guest wfi trapping 

virt inclusion
category: performance
bugzilla: https://gitee.com/openeuler/kernel/issues/IAQV1W



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

Currently, on GICv4+ system if a vCPU is only runnable process
on a pCPU and we are using direct injection of interrupts, the
guest WFI trapping will be turn off. So in host view, the vcpu
process's CPU util is almost 100%, which may confuse someone.
Let's add a kvm parameter to control guest wfi trapping.

Signed-off-by: default avatarZhiqiang Ni <nizhiqiang1@huawei.com>
parent ea308216

arch/arm64/include/asm/kvm_emulate.h

+3 −0
Original line number Diff line number Diff line
@@ -119,6 +119,9 @@ static inline void vcpu_clear_wfx_traps(struct kvm_vcpu *vcpu) 
		vcpu->arch.hcr_el2 &= ~HCR_TWI;

	else

		vcpu->arch.hcr_el2 |= HCR_TWI;



	if (force_wfi_trap)

		vcpu->arch.hcr_el2 |= HCR_TWI;

}



static inline void vcpu_set_wfx_traps(struct kvm_vcpu *vcpu)

arch/arm64/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ 
#define KVM_REQ_SUSPEND		KVM_ARCH_REQ(6)

#define KVM_REQ_RESYNC_PMU_EL0	KVM_ARCH_REQ(7)

#define KVM_REQ_RELOAD_TLBI_DVMBM	KVM_ARCH_REQ(8)

#define KVM_REQ_RELOAD_WFI_TRAPS       KVM_ARCH_REQ(9)



#define KVM_DIRTY_LOG_MANUAL_CAPS   (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | \

				     KVM_DIRTY_LOG_INITIALLY_SET)
@@ -1284,6 +1285,7 @@ extern unsigned int twedel; 
void kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu);

bool kvm_arm_vcpu_stopped(struct kvm_vcpu *vcpu);



extern bool force_wfi_trap;

extern bool kvm_ncsnp_support;

extern bool kvm_dvmbm_support;

arch/arm64/kvm/arm.c

+49 −0
Original line number Diff line number Diff line
@@ -83,6 +83,48 @@ unsigned int twedel; 
module_param(twedel, uint, 0644);

#endif



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 = {

	.set = vcpu_req_reload_wfi_traps,

	.get = param_get_bool,

};



bool force_wfi_trap;

module_param_cb(force_wfi_trap, &force_wfi_trap_ops, &force_wfi_trap, 0644);



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

{

	struct kvm *kvm;

	bool oldvalue;

	int err;



	oldvalue = force_wfi_trap;

	err = param_set_bool(val, kp);

	if (err)

		return err;



	if (oldvalue == force_wfi_trap)

		return err;



	/*

	 * If set the force_wfi_trap from 1 to 0, no need to kick vcpus here.

	 * The HCR_TWI flag will be cleared in kvm_arch_vcpu_load().

	 */

	if (force_wfi_trap == 0)

		return 0;



	/*

	 * We need to kick vcpus out of guest mode here to reload

	 * wfx trapping config when re-enter guest mode.

	 */

	mutex_lock(&kvm_lock);

	list_for_each_entry(kvm, &vm_list, vm_list)

		kvm_make_all_cpus_request(kvm, KVM_REQ_RELOAD_WFI_TRAPS);

	mutex_unlock(&kvm_lock);

	return err;

}



int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)

{

	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
@@ -956,6 +998,13 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu) 


		if (kvm_check_request(KVM_REQ_RELOAD_TLBI_DVMBM, vcpu))

			kvm_hisi_reload_lsudvmbm(vcpu->kvm);



		if (kvm_check_request(KVM_REQ_RELOAD_WFI_TRAPS, vcpu)) {

			if (single_task_running())

				vcpu_clear_wfx_traps(vcpu);

			else

				vcpu_set_wfx_traps(vcpu);

		}

	}



	return 1;