linux_dsm_epyc7002/virt/kvm/arm/arch_timer.c
Linus Torvalds 3ddc76dfc7 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer type cleanups from Thomas Gleixner:
 "This series does a tree wide cleanup of types related to
  timers/timekeeping.

   - Get rid of cycles_t and use a plain u64. The type is not really
     helpful and caused more confusion than clarity

   - Get rid of the ktime union. The union has become useless as we use
     the scalar nanoseconds storage unconditionally now. The 32bit
     timespec alike storage got removed due to the Y2038 limitations
     some time ago.

     That leaves the odd union access around for no reason. Clean it up.

  Both changes have been done with coccinelle and a small amount of
  manual mopping up"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ktime: Get rid of ktime_equal()
  ktime: Cleanup ktime_set() usage
  ktime: Get rid of the union
  clocksource: Use a plain u64 instead of cycle_t
2016-12-25 14:30:04 -08:00

515 lines
13 KiB
C

/*
* Copyright (C) 2012 ARM Ltd.
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* 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/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <clocksource/arm_arch_timer.h>
#include <asm/arch_timer.h>
#include <kvm/arm_vgic.h>
#include <kvm/arm_arch_timer.h>
#include "trace.h"
static struct timecounter *timecounter;
static unsigned int host_vtimer_irq;
static u32 host_vtimer_irq_flags;
void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
{
vcpu->arch.timer_cpu.active_cleared_last = false;
}
static u64 kvm_phys_timer_read(void)
{
return timecounter->cc->read(timecounter->cc);
}
static bool timer_is_armed(struct arch_timer_cpu *timer)
{
return timer->armed;
}
/* timer_arm: as in "arm the timer", not as in ARM the company */
static void timer_arm(struct arch_timer_cpu *timer, u64 ns)
{
timer->armed = true;
hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
HRTIMER_MODE_ABS);
}
static void timer_disarm(struct arch_timer_cpu *timer)
{
if (timer_is_armed(timer)) {
hrtimer_cancel(&timer->timer);
cancel_work_sync(&timer->expired);
timer->armed = false;
}
}
static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
{
struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
/*
* We disable the timer in the world switch and let it be
* handled by kvm_timer_sync_hwstate(). Getting a timer
* interrupt at this point is a sure sign of some major
* breakage.
*/
pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
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);
vcpu->arch.timer_cpu.armed = false;
WARN_ON(!kvm_timer_should_fire(vcpu));
/*
* 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_kick(vcpu);
}
static u64 kvm_timer_compute_delta(struct kvm_vcpu *vcpu)
{
u64 cval, now;
cval = vcpu->arch.timer_cpu.cntv_cval;
now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
if (now < cval) {
u64 ns;
ns = cyclecounter_cyc2ns(timecounter->cc,
cval - now,
timecounter->mask,
&timecounter->frac);
return ns;
}
return 0;
}
static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
{
struct arch_timer_cpu *timer;
struct kvm_vcpu *vcpu;
u64 ns;
timer = container_of(hrt, struct arch_timer_cpu, timer);
vcpu = container_of(timer, struct kvm_vcpu, arch.timer_cpu);
/*
* Check that the timer has really expired from the guest's
* PoV (NTP on the host may have forced it to expire
* early). If we should have slept longer, restart it.
*/
ns = kvm_timer_compute_delta(vcpu);
if (unlikely(ns)) {
hrtimer_forward_now(hrt, ns_to_ktime(ns));
return HRTIMER_RESTART;
}
schedule_work(&timer->expired);
return HRTIMER_NORESTART;
}
static bool kvm_timer_irq_can_fire(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
return !(timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) &&
(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE);
}
bool kvm_timer_should_fire(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
u64 cval, now;
if (!kvm_timer_irq_can_fire(vcpu))
return false;
cval = timer->cntv_cval;
now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
return cval <= now;
}
static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level)
{
int ret;
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
BUG_ON(!vgic_initialized(vcpu->kvm));
timer->active_cleared_last = false;
timer->irq.level = new_level;
trace_kvm_timer_update_irq(vcpu->vcpu_id, timer->irq.irq,
timer->irq.level);
ret = kvm_vgic_inject_mapped_irq(vcpu->kvm, vcpu->vcpu_id,
timer->irq.irq,
timer->irq.level);
WARN_ON(ret);
}
/*
* Check if there was a change in the timer state (should we raise or lower
* the line level to the GIC).
*/
static int kvm_timer_update_state(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
/*
* If userspace modified the timer registers via SET_ONE_REG before
* the vgic was initialized, we mustn't set the timer->irq.level value
* because the guest would never see the interrupt. Instead wait
* until we call this function from kvm_timer_flush_hwstate.
*/
if (!vgic_initialized(vcpu->kvm) || !timer->enabled)
return -ENODEV;
if (kvm_timer_should_fire(vcpu) != timer->irq.level)
kvm_timer_update_irq(vcpu, !timer->irq.level);
return 0;
}
/*
* Schedule the background timer before calling kvm_vcpu_block, so that this
* thread is removed from its waitqueue and made runnable when there's a timer
* interrupt to handle.
*/
void kvm_timer_schedule(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
BUG_ON(timer_is_armed(timer));
/*
* No need to schedule a background timer if the guest timer has
* already expired, because kvm_vcpu_block will return before putting
* the thread to sleep.
*/
if (kvm_timer_should_fire(vcpu))
return;
/*
* If the timer is not capable of raising interrupts (disabled or
* masked), then there's no more work for us to do.
*/
if (!kvm_timer_irq_can_fire(vcpu))
return;
/* The timer has not yet expired, schedule a background timer */
timer_arm(timer, kvm_timer_compute_delta(vcpu));
}
void kvm_timer_unschedule(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
timer_disarm(timer);
}
/**
* kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
* @vcpu: The vcpu pointer
*
* Check if the virtual timer has expired while we were running in the host,
* and inject an interrupt if that was the case.
*/
void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
bool phys_active;
int ret;
if (kvm_timer_update_state(vcpu))
return;
/*
* If we enter the guest with the virtual input level to the VGIC
* asserted, then we have already told the VGIC what we need to, and
* we don't need to exit from the guest until the guest deactivates
* the already injected interrupt, so therefore we should set the
* hardware active state to prevent unnecessary exits from the guest.
*
* Also, if we enter the guest with the virtual timer interrupt active,
* then it must be active on the physical distributor, because we set
* the HW bit and the guest must be able to deactivate the virtual and
* physical interrupt at the same time.
*
* Conversely, if the virtual input level is deasserted and the virtual
* interrupt is not active, then always clear the hardware active state
* to ensure that hardware interrupts from the timer triggers a guest
* exit.
*/
phys_active = timer->irq.level ||
kvm_vgic_map_is_active(vcpu, timer->irq.irq);
/*
* We want to avoid hitting the (re)distributor as much as
* possible, as this is a potentially expensive MMIO access
* (not to mention locks in the irq layer), and a solution for
* this is to cache the "active" state in memory.
*
* Things to consider: we cannot cache an "active set" state,
* because the HW can change this behind our back (it becomes
* "clear" in the HW). We must then restrict the caching to
* the "clear" state.
*
* The cache is invalidated on:
* - vcpu put, indicating that the HW cannot be trusted to be
* in a sane state on the next vcpu load,
* - any change in the interrupt state
*
* Usage conditions:
* - cached value is "active clear"
* - value to be programmed is "active clear"
*/
if (timer->active_cleared_last && !phys_active)
return;
ret = irq_set_irqchip_state(host_vtimer_irq,
IRQCHIP_STATE_ACTIVE,
phys_active);
WARN_ON(ret);
timer->active_cleared_last = !phys_active;
}
/**
* kvm_timer_sync_hwstate - sync timer state from cpu
* @vcpu: The vcpu pointer
*
* Check if the virtual timer has expired while we were running in the guest,
* and inject an interrupt if that was the case.
*/
void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
BUG_ON(timer_is_armed(timer));
/*
* The guest could have modified the timer registers or the timer
* could have expired, update the timer state.
*/
kvm_timer_update_state(vcpu);
}
int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
const struct kvm_irq_level *irq)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
/*
* The vcpu timer irq number cannot be determined in
* kvm_timer_vcpu_init() because it is called much before
* kvm_vcpu_set_target(). To handle this, we determine
* vcpu timer irq number when the vcpu is reset.
*/
timer->irq.irq = irq->irq;
/*
* The bits in CNTV_CTL are architecturally reset to UNKNOWN for ARMv8
* and to 0 for ARMv7. We provide an implementation that always
* resets the timer to be disabled and unmasked and is compliant with
* the ARMv7 architecture.
*/
timer->cntv_ctl = 0;
kvm_timer_update_state(vcpu);
return 0;
}
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;
}
static void kvm_timer_init_interrupt(void *info)
{
enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
}
int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
switch (regid) {
case KVM_REG_ARM_TIMER_CTL:
timer->cntv_ctl = value;
break;
case KVM_REG_ARM_TIMER_CNT:
vcpu->kvm->arch.timer.cntvoff = kvm_phys_timer_read() - value;
break;
case KVM_REG_ARM_TIMER_CVAL:
timer->cntv_cval = value;
break;
default:
return -1;
}
kvm_timer_update_state(vcpu);
return 0;
}
u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
switch (regid) {
case KVM_REG_ARM_TIMER_CTL:
return timer->cntv_ctl;
case KVM_REG_ARM_TIMER_CNT:
return kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
case KVM_REG_ARM_TIMER_CVAL:
return timer->cntv_cval;
}
return (u64)-1;
}
static int kvm_timer_starting_cpu(unsigned int cpu)
{
kvm_timer_init_interrupt(NULL);
return 0;
}
static int kvm_timer_dying_cpu(unsigned int cpu)
{
disable_percpu_irq(host_vtimer_irq);
return 0;
}
int kvm_timer_hyp_init(void)
{
struct arch_timer_kvm_info *info;
int err;
info = arch_timer_get_kvm_info();
timecounter = &info->timecounter;
if (!timecounter->cc) {
kvm_err("kvm_arch_timer: uninitialized timecounter\n");
return -ENODEV;
}
if (info->virtual_irq <= 0) {
kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n",
info->virtual_irq);
return -ENODEV;
}
host_vtimer_irq = info->virtual_irq;
host_vtimer_irq_flags = irq_get_trigger_type(host_vtimer_irq);
if (host_vtimer_irq_flags != IRQF_TRIGGER_HIGH &&
host_vtimer_irq_flags != IRQF_TRIGGER_LOW) {
kvm_err("Invalid trigger for IRQ%d, assuming level low\n",
host_vtimer_irq);
host_vtimer_irq_flags = IRQF_TRIGGER_LOW;
}
err = request_percpu_irq(host_vtimer_irq, kvm_arch_timer_handler,
"kvm guest timer", kvm_get_running_vcpus());
if (err) {
kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
host_vtimer_irq, err);
return err;
}
kvm_info("virtual timer IRQ%d\n", host_vtimer_irq);
cpuhp_setup_state(CPUHP_AP_KVM_ARM_TIMER_STARTING,
"kvm/arm/timer:starting", kvm_timer_starting_cpu,
kvm_timer_dying_cpu);
return err;
}
void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
timer_disarm(timer);
kvm_vgic_unmap_phys_irq(vcpu, timer->irq.irq);
}
int kvm_timer_enable(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
struct irq_desc *desc;
struct irq_data *data;
int phys_irq;
int ret;
if (timer->enabled)
return 0;
/*
* Find the physical IRQ number corresponding to the host_vtimer_irq
*/
desc = irq_to_desc(host_vtimer_irq);
if (!desc) {
kvm_err("%s: no interrupt descriptor\n", __func__);
return -EINVAL;
}
data = irq_desc_get_irq_data(desc);
while (data->parent_data)
data = data->parent_data;
phys_irq = data->hwirq;
/*
* Tell the VGIC that the virtual interrupt is tied to a
* physical interrupt. We do that once per VCPU.
*/
ret = kvm_vgic_map_phys_irq(vcpu, timer->irq.irq, phys_irq);
if (ret)
return ret;
timer->enabled = 1;
return 0;
}
void kvm_timer_init(struct kvm *kvm)
{
kvm->arch.timer.cntvoff = kvm_phys_timer_read();
}