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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: Jintack Lim <jintack@cs.columbia.edu>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Jintack Lim 2017-02-03 10:20:08 -05:00 committed by Marc Zyngier
parent c9a3c58f01
commit 7b6b46311a
3 changed files with 37 additions and 4 deletions
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37
arch/arm64/kvm/sys_regs.c
View File

@ -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;
}

2
include/kvm/arm_arch_timer.h
View File

@ -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);

2
virt/kvm/arm/arch_timer.c
View File

@ -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);
}