Commit 8a411b06 authored by Christoffer Dall's avatar Christoffer Dall Committed by Marc Zyngier
Browse files

KVM: arm/arm64: Remove arch timer workqueue 



The use of a work queue in the hrtimer expire function for the bg_timer
is a leftover from the time when we would inject interrupts when the
bg_timer expired.

Since we are no longer doing that, we can instead call
kvm_vcpu_wake_up() directly from the hrtimer function and remove all
workqueue functionality from the arch timer code.

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 71a7e47f

include/kvm/arm_arch_timer.h

+0 −4
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ 


#include <linux/clocksource.h>

#include <linux/hrtimer.h>

#include <linux/workqueue.h>



struct arch_timer_context {

	/* Registers: control register, timer value */
@@ -52,9 +51,6 @@ struct arch_timer_cpu { 
	/* Background timer used when the guest is not running */

	struct hrtimer			bg_timer;



	/* Work queued with the above timer expires */

	struct work_struct		expired;



	/* Physical timer emulation */

	struct hrtimer			phys_timer;

virt/kvm/arm/arch_timer.c

+7 −27
Original line number Diff line number Diff line
@@ -70,11 +70,9 @@ static void soft_timer_start(struct hrtimer *hrt, u64 ns) 
		      HRTIMER_MODE_ABS);

}



static void soft_timer_cancel(struct hrtimer *hrt, struct work_struct *work)

static void soft_timer_cancel(struct hrtimer *hrt)

{

	hrtimer_cancel(hrt);

	if (work)

		cancel_work_sync(work);

}



static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
@@ -102,23 +100,6 @@ static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



/*

 * Work function for handling the backup timer that we schedule when a vcpu is

 * no longer running, but had a timer programmed to fire in the future.

 */

static void kvm_timer_inject_irq_work(struct work_struct *work)

{

	struct kvm_vcpu *vcpu;



	vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired);



	/*

	 * If the vcpu is blocked we want to wake it up so that it will see

	 * the timer has expired when entering the guest.

	 */

	kvm_vcpu_wake_up(vcpu);

}



static u64 kvm_timer_compute_delta(struct arch_timer_context *timer_ctx)

{

	u64 cval, now;
@@ -188,7 +169,7 @@ static enum hrtimer_restart kvm_bg_timer_expire(struct hrtimer *hrt) 
		return HRTIMER_RESTART;

	}



	schedule_work(&timer->expired);

	kvm_vcpu_wake_up(vcpu);

	return HRTIMER_NORESTART;

}
@@ -300,7 +281,7 @@ static void phys_timer_emulate(struct kvm_vcpu *vcpu) 
	 * then we also don't need a soft timer.

	 */

	if (kvm_timer_should_fire(ptimer) || !kvm_timer_irq_can_fire(ptimer)) {

		soft_timer_cancel(&timer->phys_timer, NULL);

		soft_timer_cancel(&timer->phys_timer);

		return;

	}
@@ -426,7 +407,7 @@ void kvm_timer_unschedule(struct kvm_vcpu *vcpu) 


	vtimer_restore_state(vcpu);



	soft_timer_cancel(&timer->bg_timer, &timer->expired);

	soft_timer_cancel(&timer->bg_timer);

}



static void set_cntvoff(u64 cntvoff)
@@ -544,7 +525,7 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) 
	 * In any case, we re-schedule the hrtimer for the physical timer when

	 * coming back to the VCPU thread in kvm_timer_vcpu_load().

	 */

	soft_timer_cancel(&timer->phys_timer, NULL);

	soft_timer_cancel(&timer->phys_timer);



	/*

	 * The kernel may decide to run userspace after calling vcpu_put, so
@@ -637,7 +618,6 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) 
	update_vtimer_cntvoff(vcpu, kvm_phys_timer_read());

	vcpu_ptimer(vcpu)->cntvoff = 0;



	INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);

	hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);

	timer->bg_timer.function = kvm_bg_timer_expire;
@@ -794,8 +774,8 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) 
	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;

	struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);



	soft_timer_cancel(&timer->bg_timer, &timer->expired);

	soft_timer_cancel(&timer->phys_timer, NULL);

	soft_timer_cancel(&timer->bg_timer);

	soft_timer_cancel(&timer->phys_timer);

	kvm_vgic_unmap_phys_irq(vcpu, vtimer->irq.irq);

}

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