2 * 8259 interrupt controller emulation
4 * Copyright (c) 2003-2004 Fabrice Bellard
5 * Copyright (c) 2007 Intel Corporation
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 * Yaozu (Eddie) Dong <Eddie.dong@intel.com>
29 #include <linux/bitops.h>
32 #include <linux/kvm_host.h>
35 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
37 s->isr &= ~(1 << irq);
38 s->isr_ack |= (1 << irq);
39 if (s != &s->pics_state->pics[0])
41 kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
44 void kvm_pic_clear_isr_ack(struct kvm *kvm)
46 struct kvm_pic *s = pic_irqchip(kvm);
48 s->pics[0].isr_ack = 0xff;
49 s->pics[1].isr_ack = 0xff;
50 spin_unlock(&s->lock);
54 * set irq level. If an edge is detected, then the IRR is set to 1
56 static inline int pic_set_irq1(struct kvm_kpic_state *s, int irq, int level)
60 if (s->elcr & mask) /* level triggered */
62 ret = !(s->irr & mask);
69 else /* edge triggered */
71 if ((s->last_irr & mask) == 0) {
72 ret = !(s->irr & mask);
79 return (s->imr & mask) ? -1 : ret;
83 * return the highest priority found in mask (highest = smallest
84 * number). Return 8 if no irq
86 static inline int get_priority(struct kvm_kpic_state *s, int mask)
92 while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
98 * return the pic wanted interrupt. return -1 if none
100 static int pic_get_irq(struct kvm_kpic_state *s)
102 int mask, cur_priority, priority;
104 mask = s->irr & ~s->imr;
105 priority = get_priority(s, mask);
109 * compute current priority. If special fully nested mode on the
110 * master, the IRQ coming from the slave is not taken into account
111 * for the priority computation.
114 if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
116 cur_priority = get_priority(s, mask);
117 if (priority < cur_priority)
119 * higher priority found: an irq should be generated
121 return (priority + s->priority_add) & 7;
127 * raise irq to CPU if necessary. must be called every time the active
130 static void pic_update_irq(struct kvm_pic *s)
134 irq2 = pic_get_irq(&s->pics[1]);
137 * if irq request by slave pic, signal master PIC
139 pic_set_irq1(&s->pics[0], 2, 1);
140 pic_set_irq1(&s->pics[0], 2, 0);
142 irq = pic_get_irq(&s->pics[0]);
144 s->irq_request(s->irq_request_opaque, 1);
146 s->irq_request(s->irq_request_opaque, 0);
149 void kvm_pic_update_irq(struct kvm_pic *s)
153 spin_unlock(&s->lock);
156 int kvm_pic_set_irq(void *opaque, int irq, int level)
158 struct kvm_pic *s = opaque;
162 if (irq >= 0 && irq < PIC_NUM_PINS) {
163 ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
165 trace_kvm_pic_set_irq(irq >> 3, irq & 7, s->pics[irq >> 3].elcr,
166 s->pics[irq >> 3].imr, ret == 0);
168 spin_unlock(&s->lock);
174 * acknowledge interrupt 'irq'
176 static inline void pic_intack(struct kvm_kpic_state *s, int irq)
180 if (s->rotate_on_auto_eoi)
181 s->priority_add = (irq + 1) & 7;
182 pic_clear_isr(s, irq);
185 * We don't clear a level sensitive interrupt here
187 if (!(s->elcr & (1 << irq)))
188 s->irr &= ~(1 << irq);
191 int kvm_pic_read_irq(struct kvm *kvm)
193 int irq, irq2, intno;
194 struct kvm_pic *s = pic_irqchip(kvm);
197 irq = pic_get_irq(&s->pics[0]);
199 pic_intack(&s->pics[0], irq);
201 irq2 = pic_get_irq(&s->pics[1]);
203 pic_intack(&s->pics[1], irq2);
206 * spurious IRQ on slave controller
209 intno = s->pics[1].irq_base + irq2;
212 intno = s->pics[0].irq_base + irq;
215 * spurious IRQ on host controller
218 intno = s->pics[0].irq_base + irq;
221 spin_unlock(&s->lock);
226 void kvm_pic_reset(struct kvm_kpic_state *s)
229 struct kvm *kvm = s->pics_state->irq_request_opaque;
230 struct kvm_vcpu *vcpu0 = kvm->bsp_vcpu;
232 if (s == &s->pics_state->pics[0])
237 for (irq = 0; irq < PIC_NUM_PINS/2; irq++) {
238 if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
239 if (s->irr & (1 << irq) || s->isr & (1 << irq)) {
241 kvm_notify_acked_irq(kvm, SELECT_PIC(n), n);
251 s->read_reg_select = 0;
256 s->rotate_on_auto_eoi = 0;
257 s->special_fully_nested_mode = 0;
261 static void pic_ioport_write(void *opaque, u32 addr, u32 val)
263 struct kvm_kpic_state *s = opaque;
264 int priority, cmd, irq;
269 kvm_pic_reset(s); /* init */
271 * deassert a pending interrupt
273 s->pics_state->irq_request(s->pics_state->
274 irq_request_opaque, 0);
278 printk(KERN_ERR "single mode not supported");
281 "level sensitive irq not supported");
282 } else if (val & 0x08) {
286 s->read_reg_select = val & 1;
288 s->special_mask = (val >> 5) & 1;
294 s->rotate_on_auto_eoi = cmd >> 2;
296 case 1: /* end of interrupt */
298 priority = get_priority(s, s->isr);
300 irq = (priority + s->priority_add) & 7;
301 pic_clear_isr(s, irq);
303 s->priority_add = (irq + 1) & 7;
304 pic_update_irq(s->pics_state);
309 pic_clear_isr(s, irq);
310 pic_update_irq(s->pics_state);
313 s->priority_add = (val + 1) & 7;
314 pic_update_irq(s->pics_state);
318 s->priority_add = (irq + 1) & 7;
319 pic_clear_isr(s, irq);
320 pic_update_irq(s->pics_state);
323 break; /* no operation */
327 switch (s->init_state) {
328 case 0: /* normal mode */
330 pic_update_irq(s->pics_state);
333 s->irq_base = val & 0xf8;
343 s->special_fully_nested_mode = (val >> 4) & 1;
344 s->auto_eoi = (val >> 1) & 1;
350 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
354 ret = pic_get_irq(s);
357 s->pics_state->pics[0].isr &= ~(1 << 2);
358 s->pics_state->pics[0].irr &= ~(1 << 2);
360 s->irr &= ~(1 << ret);
361 pic_clear_isr(s, ret);
362 if (addr1 >> 7 || ret != 2)
363 pic_update_irq(s->pics_state);
366 pic_update_irq(s->pics_state);
372 static u32 pic_ioport_read(void *opaque, u32 addr1)
374 struct kvm_kpic_state *s = opaque;
381 ret = pic_poll_read(s, addr1);
385 if (s->read_reg_select)
394 static void elcr_ioport_write(void *opaque, u32 addr, u32 val)
396 struct kvm_kpic_state *s = opaque;
397 s->elcr = val & s->elcr_mask;
400 static u32 elcr_ioport_read(void *opaque, u32 addr1)
402 struct kvm_kpic_state *s = opaque;
406 static int picdev_in_range(gpa_t addr)
421 static inline struct kvm_pic *to_pic(struct kvm_io_device *dev)
423 return container_of(dev, struct kvm_pic, dev);
426 static int picdev_write(struct kvm_io_device *this,
427 gpa_t addr, int len, const void *val)
429 struct kvm_pic *s = to_pic(this);
430 unsigned char data = *(unsigned char *)val;
431 if (!picdev_in_range(addr))
435 if (printk_ratelimit())
436 printk(KERN_ERR "PIC: non byte write\n");
445 pic_ioport_write(&s->pics[addr >> 7], addr, data);
449 elcr_ioport_write(&s->pics[addr & 1], addr, data);
452 spin_unlock(&s->lock);
456 static int picdev_read(struct kvm_io_device *this,
457 gpa_t addr, int len, void *val)
459 struct kvm_pic *s = to_pic(this);
460 unsigned char data = 0;
461 if (!picdev_in_range(addr))
465 if (printk_ratelimit())
466 printk(KERN_ERR "PIC: non byte read\n");
475 data = pic_ioport_read(&s->pics[addr >> 7], addr);
479 data = elcr_ioport_read(&s->pics[addr & 1], addr);
482 *(unsigned char *)val = data;
483 spin_unlock(&s->lock);
488 * callback when PIC0 irq status changed
490 static void pic_irq_request(void *opaque, int level)
492 struct kvm *kvm = opaque;
493 struct kvm_vcpu *vcpu = kvm->bsp_vcpu;
494 struct kvm_pic *s = pic_irqchip(kvm);
495 int irq = pic_get_irq(&s->pics[0]);
498 if (vcpu && level && (s->pics[0].isr_ack & (1 << irq))) {
499 s->pics[0].isr_ack &= ~(1 << irq);
504 static const struct kvm_io_device_ops picdev_ops = {
506 .write = picdev_write,
509 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
514 s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
517 spin_lock_init(&s->lock);
519 s->pics[0].elcr_mask = 0xf8;
520 s->pics[1].elcr_mask = 0xde;
521 s->irq_request = pic_irq_request;
522 s->irq_request_opaque = kvm;
523 s->pics[0].pics_state = s;
524 s->pics[1].pics_state = s;
527 * Initialize PIO device
529 kvm_iodevice_init(&s->dev, &picdev_ops);
530 ret = kvm_io_bus_register_dev(kvm, &kvm->pio_bus, &s->dev);