linux-stable/arch/x86/kvm/i8254.h
Marcelo Tosatti 52d939a0bf KVM: PIT: provide an option to disable interrupt reinjection
Certain clocks (such as TSC) in older 2.6 guests overaccount for lost
ticks, causing severe time drift. Interrupt reinjection magnifies the
problem.

Provide an option to disable it.

[avi: allow room for expansion in case we want to disable reinjection
      of other timers]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24 11:02:55 +02:00

64 lines
1.4 KiB
C

#ifndef __I8254_H
#define __I8254_H
#include "iodev.h"
struct kvm_kpit_timer {
struct hrtimer timer;
int irq;
s64 period; /* unit: ns */
s64 scheduled;
atomic_t pending;
bool reinject;
};
struct kvm_kpit_channel_state {
u32 count; /* can be 65536 */
u16 latched_count;
u8 count_latched;
u8 status_latched;
u8 status;
u8 read_state;
u8 write_state;
u8 write_latch;
u8 rw_mode;
u8 mode;
u8 bcd; /* not supported */
u8 gate; /* timer start */
ktime_t count_load_time;
};
struct kvm_kpit_state {
struct kvm_kpit_channel_state channels[3];
struct kvm_kpit_timer pit_timer;
u32 speaker_data_on;
struct mutex lock;
struct kvm_pit *pit;
spinlock_t inject_lock;
unsigned long irq_ack;
struct kvm_irq_ack_notifier irq_ack_notifier;
};
struct kvm_pit {
unsigned long base_addresss;
struct kvm_io_device dev;
struct kvm_io_device speaker_dev;
struct kvm *kvm;
struct kvm_kpit_state pit_state;
int irq_source_id;
};
#define KVM_PIT_BASE_ADDRESS 0x40
#define KVM_SPEAKER_BASE_ADDRESS 0x61
#define KVM_PIT_MEM_LENGTH 4
#define KVM_PIT_FREQ 1193181
#define KVM_MAX_PIT_INTR_INTERVAL HZ / 100
#define KVM_PIT_CHANNEL_MASK 0x3
void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu);
void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val);
struct kvm_pit *kvm_create_pit(struct kvm *kvm);
void kvm_free_pit(struct kvm *kvm);
void kvm_pit_reset(struct kvm_pit *pit);
#endif