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