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linux/arch/x86/kvm/i8254.h
Marcelo Tosatti 3cf57fed21 KVM: PIT: fix injection logic and count
The PIT injection logic is problematic under the following cases:

1) If there is a higher priority vector to be delivered by the time
kvm_pit_timer_intr_post is invoked ps->inject_pending won't be set.
This opens the possibility for missing many PIT event injections (say if
guest executes hlt at this point).

2) ps->inject_pending is racy with more than two vcpus. Since there's no locking
around read/dec of pt->pending, two vcpu's can inject two interrupts for a single
pt->pending count.

Fix 1 by using an irq ack notifier: only reinject when the previous irq
has been acked. Fix 2 with appropriate locking around manipulation of
pending count and irq_ack by the injection / ack paths.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:17 +02:00

63 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;
};
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;
};
#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