On Thu, Jul 5, 2012 at 12:18 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
> We can inject a timer interrupt into the guest as a result of
> three possible events:
> - The virtual timer interrupt has fired while we were still
> executing the guest
> - The timer interrupt hasn't fired, but it expired while we
> were doing the world switch
> - A hrtimer we programmed earlier has fired
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm/include/asm/kvm_arch_timer.h | 34 ++++++-
> arch/arm/kvm/timer.c | 164 +++++++++++++++++++++++++++++++++
> 2 files changed, 197 insertions(+), 1 deletion(-)
> create mode 100644 arch/arm/kvm/timer.c
>
> diff --git a/arch/arm/include/asm/kvm_arch_timer.h b/arch/arm/include/asm/kvm_arch_timer.h
> index 491e336..191c541 100644
> --- a/arch/arm/include/asm/kvm_arch_timer.h
> +++ b/arch/arm/include/asm/kvm_arch_timer.h
> @@ -1,13 +1,45 @@
> #ifndef __ASM_ARM_KVM_ARCH_TIMER_H
> #define __ASM_ARM_KVM_ARCH_TIMER_H
>
> +#include <linux/clocksource.h>
> +#include <linux/hrtimer.h>
> +#include <linux/workqueue.h>
> +
> struct arch_timer_kvm {
> +#ifdef CONFIG_KVM_ARM_TIMER
> + bool enabled;
> + union {
> + cycle_t cntvoff;
> + struct {
> + u32 cntvoff_high; /* Restored only */
> + u32 cntvoff_low; /* Restored only */
> + } cntvoff32;
> + };
> +#endif
> };
>
> struct arch_timer_cpu {
> +#ifdef CONFIG_KVM_ARM_TIMER
> + struct hrtimer timer;
> + struct work_struct expired;
> + cycle_t cval;
> + bool armed;
> +
> + /* Registers */
> + u32 cntv_ctl; /* Saved/restored */
> + u32 cntv_cval_high; /* Saved/restored */
> + u32 cntv_cval_low; /* Saved/restored */
> +#endif
> };
I still think these structures wouldn't suffer too much from a comment
explaining their purpose and reason on earth.
>
> -#ifndef CONFIG_KVM_ARM_TIMER
> +#ifdef CONFIG_KVM_ARM_TIMER
> +int kvm_timer_hyp_init(void);
> +int kvm_timer_init(struct kvm *kvm);
> +void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
> +void kvm_timer_sync_to_cpu(struct kvm_vcpu *vcpu);
> +void kvm_timer_sync_from_cpu(struct kvm_vcpu *vcpu);
> +void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
> +#else
> static inline int kvm_timer_hyp_init(void)
> {
> return 0;
> diff --git a/arch/arm/kvm/timer.c b/arch/arm/kvm/timer.c
> new file mode 100644
> index 0000000..8642b4c
> --- /dev/null
> +++ b/arch/arm/kvm/timer.c
> @@ -0,0 +1,164 @@
> +/*
> + * Copyright (C) 2012 ARM Ltd.
> + * Author: Marc Zyngier <marc.zyngier@xxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +
> +#include <linux/kvm.h>
> +#include <linux/kvm_host.h>
> +#include <linux/interrupt.h>
> +
> +#include <asm/arch_timer.h>
> +
> +#include <asm/kvm_vgic.h>
> +#include <asm/kvm_arch_timer.h>
> +
> +static const struct kvm_irq_level virt_timer_ppi = {
> + .irq = 27, /* A7/A15 specific */
now we have this nice interface to set the emulation target, can you
adjust accordingly after rebasing?
> + .level = 1,
> +};
> +
> +static struct timecounter *timecounter;
> +static struct workqueue_struct *wqueue;
> +
> +static cycle_t kvm_phys_timer_read(void)
> +{
> + return timecounter->cc->read(timecounter->cc);
> +}
> +
> +static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> +
> + timer->cntv_ctl |= 1 << 1; /* Mask the interrupt in the guest */
> + kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, &virt_timer_ppi);
> +}
> +
> +static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
> +{
> + struct kvm_vcpu *vcpu = kvm_arm_get_running_vcpu();
> +
> + if (WARN_ON(!vcpu))
> + return IRQ_NONE;
> +
> + kvm_timer_inject_irq(vcpu);
> + return IRQ_HANDLED;
> +}
> +
> +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);
> + vcpu->arch.timer_cpu.armed = false;
> + kvm_timer_inject_irq(vcpu);
> +}
> +
> +static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
> +{
> + struct arch_timer_cpu *timer;
> + timer = container_of(hrt, struct arch_timer_cpu, timer);
> + queue_work(wqueue, &timer->expired);
> + return HRTIMER_NORESTART;
> +}
> +
> +void kvm_timer_sync_to_cpu(struct kvm_vcpu *vcpu)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> +
> + /*
> + * We're about to run this vcpu again, so there is no need to
> + * keep the background timer running, as we're about to
> + * populate the CPU timer again.
> + */
> + if (timer->armed) {
> + hrtimer_cancel(&timer->timer);
> + cancel_work_sync(&timer->expired);
> + timer->armed = false;
> + }
> +}
> +
> +void kvm_timer_sync_from_cpu(struct kvm_vcpu *vcpu)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> + cycle_t cval, now;
> + u64 ns;
> +
> + /* Check if the timer is enabled and unmasked first */
> + if ((timer->cntv_ctl & 3) != 1)
> + return;
> +
> + cval = ((cycle_t)timer->cntv_cval_high << 32) | timer->cntv_cval_low;
> + now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
> +
> + BUG_ON(timer->armed);
> +
> + if (cval <= now) {
> + /*
> + * Timer has already expired while we were not
> + * looking. Inject the interrupt and carry on.
> + */
> + kvm_timer_inject_irq(vcpu);
> + return;
> + }
> +
> + timer->cval = cval;
> + timer->armed = true;
> + ns = cyclecounter_cyc2ns(timecounter->cc, cval - now);
> + hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
> + HRTIMER_MODE_ABS);
> +}
> +
> +void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> +
> + INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
> + hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> + timer->timer.function = kvm_timer_expire;
> +}
> +
> +int kvm_timer_hyp_init(void)
> +{
> + timecounter = arch_timer_get_timecounter();
> + if (!timecounter)
> + return -ENODEV;
> +
> + wqueue = create_singlethread_workqueue("kvm_arch_timer");
> + if (!wqueue)
> + return -ENOMEM;
> +
> + arch_timer_switch_to_phys(kvm_arch_timer_handler);
> + return 0;
> +}
> +
> +void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> +
> + hrtimer_cancel(&timer->timer);
> + cancel_work_sync(&timer->expired);
> +}
> +
> +int kvm_timer_init(struct kvm *kvm)
> +{
> +#if 0
> + kvm->arch.timer.cntvoff = kvm_phys_timer_read();
> +#endif
> + if (timecounter && wqueue)
> + kvm->arch.timer.enabled = 1;
> +
> + return 0;
> +}
> --
> 1.7.10.3
>
>
looks good to me.
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
