KVM: In-kernel I/O APIC model

This allows in-kernel host-side device drivers to raise guest interrupts
without going to userspace.

[avi: fix level-triggered interrupt redelivery on eoi]
[avi: add missing #include]
[avi: avoid redelivery of edge-triggered interrupt]
[avi: implement polarity]
[avi: don't deliver edge-triggered interrupts when unmasking]
[avi: fix host oops on invalid guest access]

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/Makefile

@@ -2,7 +2,7 @@
 # Makefile for Kernel-based Virtual Machine module
 #
 
-kvm-objs := kvm_main.o mmu.o x86_emulate.o i8259.o irq.o lapic.o
+kvm-objs := kvm_main.o mmu.o x86_emulate.o i8259.o irq.o lapic.o ioapic.o
 obj-$(CONFIG_KVM) += kvm.o
 kvm-intel-objs = vmx.o
 obj-$(CONFIG_KVM_INTEL) += kvm-intel.o

drivers/kvm/ioapic.c

@@ -0,0 +1,388 @@
+/*
+ *  Copyright (C) 2001  MandrakeSoft S.A.
+ *
+ *    MandrakeSoft S.A.
+ *    43, rue d'Aboukir
+ *    75002 Paris - France
+ *    http://www.linux-mandrake.com/
+ *    http://www.mandrakesoft.com/
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ *  Yunhong Jiang <yunhong.jiang@intel.com>
+ *  Yaozu (Eddie) Dong <eddie.dong@intel.com>
+ *  Based on Xen 3.1 code.
+ */
+
+#include "kvm.h"
+#include <linux/kvm.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/smp.h>
+#include <linux/hrtimer.h>
+#include <linux/io.h>
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/page.h>
+#include <asm/current.h>
+#include <asm/apicdef.h>
+#include <asm/io_apic.h>
+#include "irq.h"
+/* #define ioapic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg) */
+#define ioapic_debug(fmt, arg...)
+static void ioapic_deliver(struct kvm_ioapic *vioapic, int irq);
+
+static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
+					  unsigned long addr,
+					  unsigned long length)
+{
+	unsigned long result = 0;
+
+	switch (ioapic->ioregsel) {
+	case IOAPIC_REG_VERSION:
+		result = ((((IOAPIC_NUM_PINS - 1) & 0xff) << 16)
+			  | (IOAPIC_VERSION_ID & 0xff));
+		break;
+
+	case IOAPIC_REG_APIC_ID:
+	case IOAPIC_REG_ARB_ID:
+		result = ((ioapic->id & 0xf) << 24);
+		break;
+
+	default:
+		{
+			u32 redir_index = (ioapic->ioregsel - 0x10) >> 1;
+			u64 redir_content;
+
+			ASSERT(redir_index < IOAPIC_NUM_PINS);
+
+			redir_content = ioapic->redirtbl[redir_index].bits;
+			result = (ioapic->ioregsel & 0x1) ?
+			    (redir_content >> 32) & 0xffffffff :
+			    redir_content & 0xffffffff;
+			break;
+		}
+	}
+
+	return result;
+}
+
+static void ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
+{
+	union ioapic_redir_entry *pent;
+
+	pent = &ioapic->redirtbl[idx];
+
+	if (!pent->fields.mask) {
+		ioapic_deliver(ioapic, idx);
+		if (pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
+			pent->fields.remote_irr = 1;
+	}
+	if (!pent->fields.trig_mode)
+		ioapic->irr &= ~(1 << idx);
+}
+
+static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
+{
+	unsigned index;
+
+	switch (ioapic->ioregsel) {
+	case IOAPIC_REG_VERSION:
+		/* Writes are ignored. */
+		break;
+
+	case IOAPIC_REG_APIC_ID:
+		ioapic->id = (val >> 24) & 0xf;
+		break;
+
+	case IOAPIC_REG_ARB_ID:
+		break;
+
+	default:
+		index = (ioapic->ioregsel - 0x10) >> 1;
+
+		ioapic_debug("change redir index %x val %x", index, val);
+		if (index >= IOAPIC_NUM_PINS)
+			return;
+		if (ioapic->ioregsel & 1) {
+			ioapic->redirtbl[index].bits &= 0xffffffff;
+			ioapic->redirtbl[index].bits |= (u64) val << 32;
+		} else {
+			ioapic->redirtbl[index].bits &= ~0xffffffffULL;
+			ioapic->redirtbl[index].bits |= (u32) val;
+			ioapic->redirtbl[index].fields.remote_irr = 0;
+		}
+		if (ioapic->irr & (1 << index))
+			ioapic_service(ioapic, index);
+		break;
+	}
+}
+
+static void ioapic_inj_irq(struct kvm_ioapic *ioapic,
+			   struct kvm_lapic *target,
+			   u8 vector, u8 trig_mode, u8 delivery_mode)
+{
+	ioapic_debug("irq %d trig %d deliv %d", vector, trig_mode,
+		     delivery_mode);
+
+	ASSERT((delivery_mode == dest_Fixed) ||
+	       (delivery_mode == dest_LowestPrio));
+
+	kvm_apic_set_irq(target, vector, trig_mode);
+}
+
+static u32 ioapic_get_delivery_bitmask(struct kvm_ioapic *ioapic, u8 dest,
+				       u8 dest_mode)
+{
+	u32 mask = 0;
+	int i;
+	struct kvm *kvm = ioapic->kvm;
+	struct kvm_vcpu *vcpu;
+
+	ioapic_debug("dest %d dest_mode %d", dest, dest_mode);
+
+	if (dest_mode == 0) {	/* Physical mode. */
+		if (dest == 0xFF) {	/* Broadcast. */
+			for (i = 0; i < KVM_MAX_VCPUS; ++i)
+				if (kvm->vcpus[i] && kvm->vcpus[i]->apic)
+					mask |= 1 << i;
+			return mask;
+		}
+		for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+			vcpu = kvm->vcpus[i];
+			if (!vcpu)
+				continue;
+			if (kvm_apic_match_physical_addr(vcpu->apic, dest)) {
+				if (vcpu->apic)
+					mask = 1 << i;
+				break;
+			}
+		}
+	} else if (dest != 0)	/* Logical mode, MDA non-zero. */
+		for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+			vcpu = kvm->vcpus[i];
+			if (!vcpu)
+				continue;
+			if (vcpu->apic &&
+			    kvm_apic_match_logical_addr(vcpu->apic, dest))
+				mask |= 1 << vcpu->vcpu_id;
+		}
+	ioapic_debug("mask %x", mask);
+	return mask;
+}
+
+static void ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
+{
+	u8 dest = ioapic->redirtbl[irq].fields.dest_id;
+	u8 dest_mode = ioapic->redirtbl[irq].fields.dest_mode;
+	u8 delivery_mode = ioapic->redirtbl[irq].fields.delivery_mode;
+	u8 vector = ioapic->redirtbl[irq].fields.vector;
+	u8 trig_mode = ioapic->redirtbl[irq].fields.trig_mode;
+	u32 deliver_bitmask;
+	struct kvm_lapic *target;
+	struct kvm_vcpu *vcpu;
+	int vcpu_id;
+
+	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
+		     "vector=%x trig_mode=%x",
+		     dest, dest_mode, delivery_mode, vector, trig_mode);
+
+	deliver_bitmask = ioapic_get_delivery_bitmask(ioapic, dest, dest_mode);
+	if (!deliver_bitmask) {
+		ioapic_debug("no target on destination");
+		return;
+	}
+
+	switch (delivery_mode) {
+	case dest_LowestPrio:
+		target =
+		    kvm_apic_round_robin(ioapic->kvm, vector, deliver_bitmask);
+		if (target != NULL)
+			ioapic_inj_irq(ioapic, target, vector,
+				       trig_mode, delivery_mode);
+		else
+			ioapic_debug("null round robin: "
+				     "mask=%x vector=%x delivery_mode=%x",
+				     deliver_bitmask, vector, dest_LowestPrio);
+		break;
+	case dest_Fixed:
+		for (vcpu_id = 0; deliver_bitmask != 0; vcpu_id++) {
+			if (!(deliver_bitmask & (1 << vcpu_id)))
+				continue;
+			deliver_bitmask &= ~(1 << vcpu_id);
+			vcpu = ioapic->kvm->vcpus[vcpu_id];
+			if (vcpu) {
+				target = vcpu->apic;
+				ioapic_inj_irq(ioapic, target, vector,
+					       trig_mode, delivery_mode);
+			}
+		}
+		break;
+
+		/* TODO: NMI */
+	default:
+		printk(KERN_WARNING "Unsupported delivery mode %d\n",
+		       delivery_mode);
+		break;
+	}
+}
+
+void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
+{
+	u32 old_irr = ioapic->irr;
+	u32 mask = 1 << irq;
+	union ioapic_redir_entry entry;
+
+	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
+		entry = ioapic->redirtbl[irq];
+		level ^= entry.fields.polarity;
+		if (!level)
+			ioapic->irr &= ~mask;
+		else {
+			ioapic->irr |= mask;
+			if ((!entry.fields.trig_mode && old_irr != ioapic->irr)
+			    || !entry.fields.remote_irr)
+				ioapic_service(ioapic, irq);
+		}
+	}
+}
+
+static int get_eoi_gsi(struct kvm_ioapic *ioapic, int vector)
+{
+	int i;
+
+	for (i = 0; i < IOAPIC_NUM_PINS; i++)
+		if (ioapic->redirtbl[i].fields.vector == vector)
+			return i;
+	return -1;
+}
+
+void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)
+{
+	struct kvm_ioapic *ioapic = kvm->vioapic;
+	union ioapic_redir_entry *ent;
+	int gsi;
+
+	gsi = get_eoi_gsi(ioapic, vector);
+	if (gsi == -1) {
+		printk(KERN_WARNING "Can't find redir item for %d EOI\n",
+		       vector);
+		return;
+	}
+
+	ent = &ioapic->redirtbl[gsi];
+	ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);
+
+	ent->fields.remote_irr = 0;
+	if (!ent->fields.mask && (ioapic->irr & (1 << gsi)))
+		ioapic_deliver(ioapic, gsi);
+}
+
+static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr)
+{
+	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
+
+	return ((addr >= ioapic->base_address &&
+		 (addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
+}
+
+static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
+			     void *val)
+{
+	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
+	u32 result;
+
+	ioapic_debug("addr %lx", (unsigned long)addr);
+	ASSERT(!(addr & 0xf));	/* check alignment */
+
+	addr &= 0xff;
+	switch (addr) {
+	case IOAPIC_REG_SELECT:
+		result = ioapic->ioregsel;
+		break;
+
+	case IOAPIC_REG_WINDOW:
+		result = ioapic_read_indirect(ioapic, addr, len);
+		break;
+
+	default:
+		result = 0;
+		break;
+	}
+	switch (len) {
+	case 8:
+		*(u64 *) val = result;
+		break;
+	case 1:
+	case 2:
+	case 4:
+		memcpy(val, (char *)&result, len);
+		break;
+	default:
+		printk(KERN_WARNING "ioapic: wrong length %d\n", len);
+	}
+}
+
+static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
+			      const void *val)
+{
+	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
+	u32 data;
+
+	ioapic_debug("ioapic_mmio_write addr=%lx len=%d val=%p\n",
+		     addr, len, val);
+	ASSERT(!(addr & 0xf));	/* check alignment */
+	if (len == 4 || len == 8)
+		data = *(u32 *) val;
+	else {
+		printk(KERN_WARNING "ioapic: Unsupported size %d\n", len);
+		return;
+	}
+
+	addr &= 0xff;
+	switch (addr) {
+	case IOAPIC_REG_SELECT:
+		ioapic->ioregsel = data;
+		break;
+
+	case IOAPIC_REG_WINDOW:
+		ioapic_write_indirect(ioapic, data);
+		break;
+
+	default:
+		break;
+	}
+}
+
+int kvm_ioapic_init(struct kvm *kvm)
+{
+	struct kvm_ioapic *ioapic;
+	int i;
+
+	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
+	if (!ioapic)
+		return -ENOMEM;
+	kvm->vioapic = ioapic;
+	for (i = 0; i < IOAPIC_NUM_PINS; i++)
+		ioapic->redirtbl[i].fields.mask = 1;
+	ioapic->base_address = IOAPIC_DEFAULT_BASE_ADDRESS;
+	ioapic->dev.read = ioapic_mmio_read;
+	ioapic->dev.write = ioapic_mmio_write;
+	ioapic->dev.in_range = ioapic_in_range;
+	ioapic->dev.private = ioapic;
+	ioapic->kvm = kvm;
+	kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
+	return 0;
+}