KVM: Adds support for in-kernel mmio handlers
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index b08272bc..31846b1 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -265,6 +265,65 @@
u32 efer_reload;
};
+struct kvm_io_device {
+ void (*read)(struct kvm_io_device *this,
+ gpa_t addr,
+ int len,
+ void *val);
+ void (*write)(struct kvm_io_device *this,
+ gpa_t addr,
+ int len,
+ const void *val);
+ int (*in_range)(struct kvm_io_device *this, gpa_t addr);
+ void (*destructor)(struct kvm_io_device *this);
+
+ void *private;
+};
+
+static inline void kvm_iodevice_read(struct kvm_io_device *dev,
+ gpa_t addr,
+ int len,
+ void *val)
+{
+ dev->read(dev, addr, len, val);
+}
+
+static inline void kvm_iodevice_write(struct kvm_io_device *dev,
+ gpa_t addr,
+ int len,
+ const void *val)
+{
+ dev->write(dev, addr, len, val);
+}
+
+static inline int kvm_iodevice_inrange(struct kvm_io_device *dev, gpa_t addr)
+{
+ return dev->in_range(dev, addr);
+}
+
+static inline void kvm_iodevice_destructor(struct kvm_io_device *dev)
+{
+ dev->destructor(dev);
+}
+
+/*
+ * It would be nice to use something smarter than a linear search, TBD...
+ * Thankfully we dont expect many devices to register (famous last words :),
+ * so until then it will suffice. At least its abstracted so we can change
+ * in one place.
+ */
+struct kvm_io_bus {
+ int dev_count;
+#define NR_IOBUS_DEVS 6
+ struct kvm_io_device *devs[NR_IOBUS_DEVS];
+};
+
+void kvm_io_bus_init(struct kvm_io_bus *bus);
+void kvm_io_bus_destroy(struct kvm_io_bus *bus);
+struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus, gpa_t addr);
+void kvm_io_bus_register_dev(struct kvm_io_bus *bus,
+ struct kvm_io_device *dev);
+
struct kvm_vcpu {
struct kvm *kvm;
union {
@@ -393,6 +452,7 @@
unsigned long rmap_overflow;
struct list_head vm_list;
struct file *filp;
+ struct kvm_io_bus mmio_bus;
};
struct descriptor_table {
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 633c2ed..e157e28 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -366,6 +366,7 @@
spin_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
spin_unlock(&kvm_lock);
+ kvm_io_bus_init(&kvm->mmio_bus);
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
struct kvm_vcpu *vcpu = &kvm->vcpus[i];
@@ -474,6 +475,7 @@
spin_lock(&kvm_lock);
list_del(&kvm->vm_list);
spin_unlock(&kvm_lock);
+ kvm_io_bus_destroy(&kvm->mmio_bus);
kvm_free_vcpus(kvm);
kvm_free_physmem(kvm);
kfree(kvm);
@@ -1097,12 +1099,25 @@
return X86EMUL_UNHANDLEABLE;
}
+static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
+ gpa_t addr)
+{
+ /*
+ * Note that its important to have this wrapper function because
+ * in the very near future we will be checking for MMIOs against
+ * the LAPIC as well as the general MMIO bus
+ */
+ return kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr);
+}
+
static int emulator_read_emulated(unsigned long addr,
void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
- struct kvm_vcpu *vcpu = ctxt->vcpu;
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+ struct kvm_io_device *mmio_dev;
+ gpa_t gpa;
if (vcpu->mmio_read_completed) {
memcpy(val, vcpu->mmio_data, bytes);
@@ -1111,18 +1126,26 @@
} else if (emulator_read_std(addr, val, bytes, ctxt)
== X86EMUL_CONTINUE)
return X86EMUL_CONTINUE;
- else {
- gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
- if (gpa == UNMAPPED_GVA)
- return X86EMUL_PROPAGATE_FAULT;
- vcpu->mmio_needed = 1;
- vcpu->mmio_phys_addr = gpa;
- vcpu->mmio_size = bytes;
- vcpu->mmio_is_write = 0;
+ gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
+ if (gpa == UNMAPPED_GVA)
+ return X86EMUL_PROPAGATE_FAULT;
- return X86EMUL_UNHANDLEABLE;
+ /*
+ * Is this MMIO handled locally?
+ */
+ mmio_dev = vcpu_find_mmio_dev(vcpu, gpa);
+ if (mmio_dev) {
+ kvm_iodevice_read(mmio_dev, gpa, bytes, val);
+ return X86EMUL_CONTINUE;
}
+
+ vcpu->mmio_needed = 1;
+ vcpu->mmio_phys_addr = gpa;
+ vcpu->mmio_size = bytes;
+ vcpu->mmio_is_write = 0;
+
+ return X86EMUL_UNHANDLEABLE;
}
static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
@@ -1150,8 +1173,9 @@
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
- struct kvm_vcpu *vcpu = ctxt->vcpu;
- gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+ struct kvm_io_device *mmio_dev;
+ gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
if (gpa == UNMAPPED_GVA) {
kvm_arch_ops->inject_page_fault(vcpu, addr, 2);
@@ -1161,6 +1185,15 @@
if (emulator_write_phys(vcpu, gpa, val, bytes))
return X86EMUL_CONTINUE;
+ /*
+ * Is this MMIO handled locally?
+ */
+ mmio_dev = vcpu_find_mmio_dev(vcpu, gpa);
+ if (mmio_dev) {
+ kvm_iodevice_write(mmio_dev, gpa, bytes, val);
+ return X86EMUL_CONTINUE;
+ }
+
vcpu->mmio_needed = 1;
vcpu->mmio_phys_addr = gpa;
vcpu->mmio_size = bytes;
@@ -3031,6 +3064,43 @@
return NOTIFY_OK;
}
+void kvm_io_bus_init(struct kvm_io_bus *bus)
+{
+ memset(bus, 0, sizeof(*bus));
+}
+
+void kvm_io_bus_destroy(struct kvm_io_bus *bus)
+{
+ int i;
+
+ for (i = 0; i < bus->dev_count; i++) {
+ struct kvm_io_device *pos = bus->devs[i];
+
+ kvm_iodevice_destructor(pos);
+ }
+}
+
+struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus, gpa_t addr)
+{
+ int i;
+
+ for (i = 0; i < bus->dev_count; i++) {
+ struct kvm_io_device *pos = bus->devs[i];
+
+ if (pos->in_range(pos, addr))
+ return pos;
+ }
+
+ return NULL;
+}
+
+void kvm_io_bus_register_dev(struct kvm_io_bus *bus, struct kvm_io_device *dev)
+{
+ BUG_ON(bus->dev_count > (NR_IOBUS_DEVS-1));
+
+ bus->devs[bus->dev_count++] = dev;
+}
+
static struct notifier_block kvm_cpu_notifier = {
.notifier_call = kvm_cpu_hotplug,
.priority = 20, /* must be > scheduler priority */