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Commit 7b6b4631 authored by Jintack Lim's avatar Jintack Lim Committed by Marc Zyngier
Browse files

KVM: arm/arm64: Emulate the EL1 phys timer registers 



Emulate read and write operations to CNTP_TVAL, CNTP_CVAL and CNTP_CTL.
Now VMs are able to use the EL1 physical timer.

Signed-off-by: default avatarJintack Lim <jintack@cs.columbia.edu>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent c9a3c58f

arch/arm64/kvm/sys_regs.c

+34 −3
Original line number Diff line number Diff line
@@ -824,7 +824,14 @@ static bool access_cntp_tval(struct kvm_vcpu *vcpu, 
		struct sys_reg_params *p,

		const struct sys_reg_desc *r)

{

	kvm_inject_undefined(vcpu);

	struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);

	u64 now = kvm_phys_timer_read();



	if (p->is_write)

		ptimer->cnt_cval = p->regval + now;

	else

		p->regval = ptimer->cnt_cval - now;



	return true;

}
@@ -832,7 +839,25 @@ static bool access_cntp_ctl(struct kvm_vcpu *vcpu, 
		struct sys_reg_params *p,

		const struct sys_reg_desc *r)

{

	kvm_inject_undefined(vcpu);

	struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);



	if (p->is_write) {

		/* ISTATUS bit is read-only */

		ptimer->cnt_ctl = p->regval & ~ARCH_TIMER_CTRL_IT_STAT;

	} else {

		u64 now = kvm_phys_timer_read();



		p->regval = ptimer->cnt_ctl;

		/*

		 * Set ISTATUS bit if it's expired.

		 * Note that according to ARMv8 ARM Issue A.k, ISTATUS bit is

		 * UNKNOWN when ENABLE bit is 0, so we chose to set ISTATUS bit

		 * regardless of ENABLE bit for our implementation convenience.

		 */

		if (ptimer->cnt_cval <= now)

			p->regval |= ARCH_TIMER_CTRL_IT_STAT;

	}



	return true;

}
@@ -840,7 +865,13 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu, 
		struct sys_reg_params *p,

		const struct sys_reg_desc *r)

{

	kvm_inject_undefined(vcpu);

	struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);



	if (p->is_write)

		ptimer->cnt_cval = p->regval;

	else

		p->regval = ptimer->cnt_cval;



	return true;

}

include/kvm/arm_arch_timer.h

+2 −0
Original line number Diff line number Diff line
@@ -72,6 +72,8 @@ bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx); 
void kvm_timer_schedule(struct kvm_vcpu *vcpu);

void kvm_timer_unschedule(struct kvm_vcpu *vcpu);



u64 kvm_phys_timer_read(void);



void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu);



void kvm_timer_init_vhe(void);

virt/kvm/arm/arch_timer.c

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) 
	vcpu_vtimer(vcpu)->active_cleared_last = false;

}



static u64 kvm_phys_timer_read(void)

u64 kvm_phys_timer_read(void)

{

	return timecounter->cc->read(timecounter->cc);

}