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>

1 files changed, 388 insertions, 0 deletions

diff --git a/drivers/kvm/ioapic.c b/drivers/kvm/ioapic.c
new file mode 100644
index 000000000000..c7992e667fdb
--- /dev/null
+++ b/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;
+}