KVM: In kernel PIT model

The patch moves the PIT model from userspace to kernel, and increases
the timer accuracy greatly.

[marcelo: make last_injected_time per-guest]

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Tested-and-Acked-by: Alex Davis <alex14641@yahoo.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
new file mode 100644
index 00000000000..d77d6b795a1
--- /dev/null
+++ b/arch/x86/kvm/i8254.h
@@ -0,0 +1,61 @@
+#ifndef __I8254_H
+#define __I8254_H
+
+#include "iodev.h"
+
+struct kvm_kpit_timer {
+	struct hrtimer timer;
+	int irq;
+	s64 period; /* unit: ns */
+	s64 scheduled;
+	ktime_t last_update;
+	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;
+	bool inject_pending; /* if inject pending interrupts */
+	unsigned long last_injected_time;
+};
+
+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_timer_intr_post(struct kvm_vcpu *vcpu, int vec);
+struct kvm_pit *kvm_create_pit(struct kvm *kvm);
+void kvm_free_pit(struct kvm *kvm);
+
+#endif