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Subject[PATCH 16/43] KVM: unify part of generic timer handling
Date
From: Marcelo Tosatti <mtosatti@redhat.com>

Hide the internals of vcpu awakening / injection from the in-kernel
emulated timers. This makes future changes in this logic easier and
decreases the distance to more generic timer handling.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/Makefile | 2 +-
arch/x86/kvm/i8254.c | 57 ++++++++++------------------
arch/x86/kvm/i8254.h | 11 +----
arch/x86/kvm/kvm_timer.h | 18 +++++++++
arch/x86/kvm/lapic.c | 94 +++++++++++++++++++---------------------------
arch/x86/kvm/lapic.h | 9 +---
arch/x86/kvm/timer.c | 46 ++++++++++++++++++++++
7 files changed, 129 insertions(+), 108 deletions(-)
create mode 100644 arch/x86/kvm/kvm_timer.h
create mode 100644 arch/x86/kvm/timer.c

diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index d3ec292..b43c4ef 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -14,7 +14,7 @@ endif
EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm

kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o \
- i8254.o
+ i8254.o timer.o
obj-$(CONFIG_KVM) += kvm.o
kvm-intel-objs = vmx.o
obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 09ae841..4e2e3f2 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -219,25 +219,6 @@ static void pit_latch_status(struct kvm *kvm, int channel)
}
}

-static int __pit_timer_fn(struct kvm_kpit_state *ps)
-{
- struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0];
- struct kvm_kpit_timer *pt = &ps->pit_timer;
-
- if (!atomic_inc_and_test(&pt->pending))
- set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests);
-
- if (!pt->reinject)
- atomic_set(&pt->pending, 1);
-
- if (vcpu0 && waitqueue_active(&vcpu0->wq))
- wake_up_interruptible(&vcpu0->wq);
-
- hrtimer_add_expires_ns(&pt->timer, pt->period);
-
- return (pt->period == 0 ? 0 : 1);
-}
-
int pit_has_pending_timer(struct kvm_vcpu *vcpu)
{
struct kvm_pit *pit = vcpu->kvm->arch.vpit;
@@ -258,21 +239,6 @@ static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
spin_unlock(&ps->inject_lock);
}

-static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
-{
- struct kvm_kpit_state *ps;
- int restart_timer = 0;
-
- ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
-
- restart_timer = __pit_timer_fn(ps);
-
- if (restart_timer)
- return HRTIMER_RESTART;
- else
- return HRTIMER_NORESTART;
-}
-
void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
{
struct kvm_pit *pit = vcpu->kvm->arch.vpit;
@@ -286,15 +252,26 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}

-static void destroy_pit_timer(struct kvm_kpit_timer *pt)
+static void destroy_pit_timer(struct kvm_timer *pt)
{
pr_debug("pit: execute del timer!\n");
hrtimer_cancel(&pt->timer);
}

+static bool kpit_is_periodic(struct kvm_timer *ktimer)
+{
+ struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
+ pit_timer);
+ return ps->is_periodic;
+}
+
+struct kvm_timer_ops kpit_ops = {
+ .is_periodic = kpit_is_periodic,
+};
+
static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
{
- struct kvm_kpit_timer *pt = &ps->pit_timer;
+ struct kvm_timer *pt = &ps->pit_timer;
s64 interval;

interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
@@ -304,7 +281,13 @@ static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
/* TODO The new value only affected after the retriggered */
hrtimer_cancel(&pt->timer);
pt->period = (is_period == 0) ? 0 : interval;
- pt->timer.function = pit_timer_fn;
+ ps->is_periodic = is_period;
+
+ pt->timer.function = kvm_timer_fn;
+ pt->t_ops = &kpit_ops;
+ pt->kvm = ps->pit->kvm;
+ pt->vcpu_id = 0;
+
atomic_set(&pt->pending, 0);
ps->irq_ack = 1;

diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index 521accf..bbd863f 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -3,14 +3,6 @@

#include "iodev.h"

-struct kvm_kpit_timer {
- struct hrtimer timer;
- int irq;
- s64 period; /* unit: ns */
- atomic_t pending;
- bool reinject;
-};
-
struct kvm_kpit_channel_state {
u32 count; /* can be 65536 */
u16 latched_count;
@@ -29,7 +21,8 @@ struct kvm_kpit_channel_state {

struct kvm_kpit_state {
struct kvm_kpit_channel_state channels[3];
- struct kvm_kpit_timer pit_timer;
+ struct kvm_timer pit_timer;
+ bool is_periodic;
u32 speaker_data_on;
struct mutex lock;
struct kvm_pit *pit;
diff --git a/arch/x86/kvm/kvm_timer.h b/arch/x86/kvm/kvm_timer.h
new file mode 100644
index 0000000..26bd6ba
--- /dev/null
+++ b/arch/x86/kvm/kvm_timer.h
@@ -0,0 +1,18 @@
+
+struct kvm_timer {
+ struct hrtimer timer;
+ s64 period; /* unit: ns */
+ atomic_t pending; /* accumulated triggered timers */
+ bool reinject;
+ struct kvm_timer_ops *t_ops;
+ struct kvm *kvm;
+ int vcpu_id;
+};
+
+struct kvm_timer_ops {
+ bool (*is_periodic)(struct kvm_timer *);
+};
+
+
+enum hrtimer_restart kvm_timer_fn(struct hrtimer *data);
+
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index afc59b2..27ca43e 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -528,12 +528,13 @@ static u32 apic_get_tmcct(struct kvm_lapic *apic)
if (apic_get_reg(apic, APIC_TMICT) == 0)
return 0;

- remaining = hrtimer_expires_remaining(&apic->timer.dev);
+ remaining = hrtimer_expires_remaining(&apic->lapic_timer.timer);
if (ktime_to_ns(remaining) < 0)
remaining = ktime_set(0, 0);

- ns = mod_64(ktime_to_ns(remaining), apic->timer.period);
- tmcct = div64_u64(ns, (APIC_BUS_CYCLE_NS * apic->timer.divide_count));
+ ns = mod_64(ktime_to_ns(remaining), apic->lapic_timer.period);
+ tmcct = div64_u64(ns,
+ (APIC_BUS_CYCLE_NS * apic->divide_count));

return tmcct;
}
@@ -620,25 +621,25 @@ static void update_divide_count(struct kvm_lapic *apic)
tdcr = apic_get_reg(apic, APIC_TDCR);
tmp1 = tdcr & 0xf;
tmp2 = ((tmp1 & 0x3) | ((tmp1 & 0x8) >> 1)) + 1;
- apic->timer.divide_count = 0x1 << (tmp2 & 0x7);
+ apic->divide_count = 0x1 << (tmp2 & 0x7);

apic_debug("timer divide count is 0x%x\n",
- apic->timer.divide_count);
+ apic->lapic_timer.divide_count);
}

static void start_apic_timer(struct kvm_lapic *apic)
{
- ktime_t now = apic->timer.dev.base->get_time();
+ ktime_t now = apic->lapic_timer.timer.base->get_time();

- apic->timer.period = apic_get_reg(apic, APIC_TMICT) *
- APIC_BUS_CYCLE_NS * apic->timer.divide_count;
- atomic_set(&apic->timer.pending, 0);
+ apic->lapic_timer.period = apic_get_reg(apic, APIC_TMICT) *
+ APIC_BUS_CYCLE_NS * apic->divide_count;
+ atomic_set(&apic->lapic_timer.pending, 0);

- if (!apic->timer.period)
+ if (!apic->lapic_timer.period)
return;

- hrtimer_start(&apic->timer.dev,
- ktime_add_ns(now, apic->timer.period),
+ hrtimer_start(&apic->lapic_timer.timer,
+ ktime_add_ns(now, apic->lapic_timer.period),
HRTIMER_MODE_ABS);

apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
@@ -647,9 +648,9 @@ static void start_apic_timer(struct kvm_lapic *apic)
"expire @ 0x%016" PRIx64 ".\n", __func__,
APIC_BUS_CYCLE_NS, ktime_to_ns(now),
apic_get_reg(apic, APIC_TMICT),
- apic->timer.period,
+ apic->lapic_timer.period,
ktime_to_ns(ktime_add_ns(now,
- apic->timer.period)));
+ apic->lapic_timer.period)));
}

static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
@@ -731,7 +732,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
apic_set_reg(apic, APIC_LVTT + 0x10 * i,
lvt_val | APIC_LVT_MASKED);
}
- atomic_set(&apic->timer.pending, 0);
+ atomic_set(&apic->lapic_timer.pending, 0);

}
break;
@@ -763,7 +764,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
break;

case APIC_TMICT:
- hrtimer_cancel(&apic->timer.dev);
+ hrtimer_cancel(&apic->lapic_timer.timer);
apic_set_reg(apic, APIC_TMICT, val);
start_apic_timer(apic);
return;
@@ -803,7 +804,7 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu)
if (!vcpu->arch.apic)
return;

- hrtimer_cancel(&vcpu->arch.apic->timer.dev);
+ hrtimer_cancel(&vcpu->arch.apic->lapic_timer.timer);

if (vcpu->arch.apic->regs_page)
__free_page(vcpu->arch.apic->regs_page);
@@ -881,7 +882,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu)
ASSERT(apic != NULL);

/* Stop the timer in case it's a reset to an active apic */
- hrtimer_cancel(&apic->timer.dev);
+ hrtimer_cancel(&apic->lapic_timer.timer);

apic_set_reg(apic, APIC_ID, vcpu->vcpu_id << 24);
apic_set_reg(apic, APIC_LVR, APIC_VERSION);
@@ -906,7 +907,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu)
apic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
}
update_divide_count(apic);
- atomic_set(&apic->timer.pending, 0);
+ atomic_set(&apic->lapic_timer.pending, 0);
if (vcpu->vcpu_id == 0)
vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;
apic_update_ppr(apic);
@@ -937,22 +938,11 @@ EXPORT_SYMBOL_GPL(kvm_lapic_enabled);
*----------------------------------------------------------------------
*/

-/* TODO: make sure __apic_timer_fn runs in current pCPU */
-static int __apic_timer_fn(struct kvm_lapic *apic)
+static bool lapic_is_periodic(struct kvm_timer *ktimer)
{
- int result = 0;
- wait_queue_head_t *q = &apic->vcpu->wq;
-
- if(!atomic_inc_and_test(&apic->timer.pending))
- set_bit(KVM_REQ_PENDING_TIMER, &apic->vcpu->requests);
- if (waitqueue_active(q))
- wake_up_interruptible(q);
-
- if (apic_lvtt_period(apic)) {
- result = 1;
- hrtimer_add_expires_ns(&apic->timer.dev, apic->timer.period);
- }
- return result;
+ struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic,
+ lapic_timer);
+ return apic_lvtt_period(apic);
}

int apic_has_pending_timer(struct kvm_vcpu *vcpu)
@@ -960,7 +950,7 @@ int apic_has_pending_timer(struct kvm_vcpu *vcpu)
struct kvm_lapic *lapic = vcpu->arch.apic;

if (lapic && apic_enabled(lapic) && apic_lvt_enabled(lapic, APIC_LVTT))
- return atomic_read(&lapic->timer.pending);
+ return atomic_read(&lapic->lapic_timer.pending);

return 0;
}
@@ -987,20 +977,9 @@ void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu)
kvm_apic_local_deliver(apic, APIC_LVT0);
}

-static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
-{
- struct kvm_lapic *apic;
- int restart_timer = 0;
-
- apic = container_of(data, struct kvm_lapic, timer.dev);
-
- restart_timer = __apic_timer_fn(apic);
-
- if (restart_timer)
- return HRTIMER_RESTART;
- else
- return HRTIMER_NORESTART;
-}
+struct kvm_timer_ops lapic_timer_ops = {
+ .is_periodic = lapic_is_periodic,
+};

int kvm_create_lapic(struct kvm_vcpu *vcpu)
{
@@ -1025,8 +1004,13 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
memset(apic->regs, 0, PAGE_SIZE);
apic->vcpu = vcpu;

- hrtimer_init(&apic->timer.dev, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
- apic->timer.dev.function = apic_timer_fn;
+ hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_ABS);
+ apic->lapic_timer.timer.function = kvm_timer_fn;
+ apic->lapic_timer.t_ops = &lapic_timer_ops;
+ apic->lapic_timer.kvm = vcpu->kvm;
+ apic->lapic_timer.vcpu_id = vcpu->vcpu_id;
+
apic->base_address = APIC_DEFAULT_PHYS_BASE;
vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE;

@@ -1079,9 +1063,9 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;

- if (apic && atomic_read(&apic->timer.pending) > 0) {
+ if (apic && atomic_read(&apic->lapic_timer.pending) > 0) {
if (kvm_apic_local_deliver(apic, APIC_LVTT))
- atomic_dec(&apic->timer.pending);
+ atomic_dec(&apic->lapic_timer.pending);
}
}

@@ -1107,7 +1091,7 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu)
MSR_IA32_APICBASE_BASE;
apic_set_reg(apic, APIC_LVR, APIC_VERSION);
apic_update_ppr(apic);
- hrtimer_cancel(&apic->timer.dev);
+ hrtimer_cancel(&apic->lapic_timer.timer);
update_divide_count(apic);
start_apic_timer(apic);
}
@@ -1120,7 +1104,7 @@ void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
if (!apic)
return;

- timer = &apic->timer.dev;
+ timer = &apic->lapic_timer.timer;
if (hrtimer_cancel(timer))
hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 45ab6ee..2fc0d3c 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -2,18 +2,15 @@
#define __KVM_X86_LAPIC_H

#include "iodev.h"
+#include "kvm_timer.h"

#include <linux/kvm_host.h>

struct kvm_lapic {
unsigned long base_address;
struct kvm_io_device dev;
- struct {
- atomic_t pending;
- s64 period; /* unit: ns */
- u32 divide_count;
- struct hrtimer dev;
- } timer;
+ struct kvm_timer lapic_timer;
+ u32 divide_count;
struct kvm_vcpu *vcpu;
struct page *regs_page;
void *regs;
diff --git a/arch/x86/kvm/timer.c b/arch/x86/kvm/timer.c
new file mode 100644
index 0000000..86dbac0
--- /dev/null
+++ b/arch/x86/kvm/timer.c
@@ -0,0 +1,46 @@
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+#include <linux/hrtimer.h>
+#include <asm/atomic.h>
+#include "kvm_timer.h"
+
+static int __kvm_timer_fn(struct kvm_vcpu *vcpu, struct kvm_timer *ktimer)
+{
+ int restart_timer = 0;
+ wait_queue_head_t *q = &vcpu->wq;
+
+ /* FIXME: this code should not know anything about vcpus */
+ if (!atomic_inc_and_test(&ktimer->pending))
+ set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
+
+ if (!ktimer->reinject)
+ atomic_set(&ktimer->pending, 1);
+
+ if (waitqueue_active(q))
+ wake_up_interruptible(q);
+
+ if (ktimer->t_ops->is_periodic(ktimer)) {
+ hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
+ restart_timer = 1;
+ }
+
+ return restart_timer;
+}
+
+enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
+{
+ int restart_timer;
+ struct kvm_vcpu *vcpu;
+ struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
+
+ vcpu = ktimer->kvm->vcpus[ktimer->vcpu_id];
+ if (!vcpu)
+ return HRTIMER_NORESTART;
+
+ restart_timer = __kvm_timer_fn(vcpu, ktimer);
+ if (restart_timer)
+ return HRTIMER_RESTART;
+ else
+ return HRTIMER_NORESTART;
+}
+
--
1.6.0.6


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