[PATCH 2/3] kvm: virtual device support

["Michael S. Tsirkin" <mst@redhat.com>]

Implement virt_hypervisor in kvm, and add support for creating virtual devices.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/kvm.h      |   13 ++++++++++++
 include/linux/kvm_host.h |    3 ++
 virt/kvm/kvm_main.c      |   47 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 0 deletions(-)

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 8cc1379..8f6cc79 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -487,6 +487,8 @@ struct kvm_irq_routing {
 #define KVM_REINJECT_CONTROL      _IO(KVMIO, 0x71)
 #define KVM_DEASSIGN_PCI_DEVICE _IOW(KVMIO, 0x72, \
 				     struct kvm_assigned_pci_dev)
+#define KVM_CREATE_VIRT_DEVICE  _IOW(KVMIO, 0x73, \
+				     struct kvm_create_virt_device)
 
 /*
  * ioctls for vcpu fds
@@ -602,6 +604,17 @@ struct kvm_assigned_irq {
 	};
 };
 
+struct kvm_create_virt_device {
+	__s32 flags; /* flags from open(2). Only O_CLOEXEC supported for now. */
+	__u32 id_len;
+	union {
+		__u32 reserved[12];
+	};
+	/* Followed by up to MAX_ID_LEN byte id. */
+};
+
+#define KVM_VIRT_DEVICE_MAX_ID_LEN	200
+
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 
 #define KVM_DEV_IRQ_ASSIGN_MSI_ACTION	KVM_DEV_IRQ_ASSIGN_ENABLE_MSI
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 894a56e..7131851 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -26,6 +26,8 @@
 
 #include <asm/kvm_host.h>
 
+#include <linux/virt.h>
+
 /*
  * vcpu->requests bit members
  */
@@ -152,6 +154,7 @@ struct kvm {
 	unsigned long mmu_notifier_seq;
 	long mmu_notifier_count;
 #endif
+	struct virt_hypervisor hypervisor;
 };
 
 /* The guest did something we don't support. */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1ecbe23..c0487f0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -766,6 +766,24 @@ static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
 	kvm_arch_flush_shadow(kvm);
 }
 
+static void kvm_hypervisor_get(struct virt_hypervisor *h)
+{
+	struct kvm *kvm = container_of(h, struct kvm, hypervisor);
+	kvm_get_kvm(kvm);
+}
+
+static void kvm_hypervisor_put(struct virt_hypervisor *h)
+{
+	struct kvm *kvm = container_of(h, struct kvm, hypervisor);
+	kvm_put_kvm(kvm);
+}
+static int kvm_hypervisor_set_irq(struct virt_hypervisor *h,
+				  int source, int irq, int level)
+{
+	struct kvm *kvm = container_of(h, struct kvm, hypervisor);
+	return kvm_set_irq(kvm, source, irq, level);
+}
+
 static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
 	.invalidate_page	= kvm_mmu_notifier_invalidate_page,
 	.invalidate_range_start	= kvm_mmu_notifier_invalidate_range_start,
@@ -828,6 +846,10 @@ static struct kvm *kvm_create_vm(void)
 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
 	kvm_coalesced_mmio_init(kvm);
 #endif
+	kvm->hypervisor.get = kvm_hypervisor_get;
+	kvm->hypervisor.put = kvm_hypervisor_put;
+	kvm->hypervisor.set_irq = kvm_hypervisor_set_irq;
+	virt_hypervisor_register(&kvm->hypervisor);
 out:
 	return kvm;
 }
@@ -865,6 +887,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 {
 	struct mm_struct *mm = kvm->mm;
 
+	virt_hypervisor_unregister(&kvm->hypervisor);
 	kvm_arch_sync_events(kvm);
 	spin_lock(&kvm_lock);
 	list_del(&kvm->vm_list);
@@ -1917,6 +1940,30 @@ static long kvm_vm_ioctl(struct file *filp,
 		vfree(entries);
 		break;
 	}
+	case KVM_CREATE_VIRT_DEVICE: {
+		struct kvm_create_virt_device d;
+		u8 *id;
+		r = -EFAULT;
+		if (copy_from_user(&d, argp, sizeof d))
+			goto out;
+		r = -EINVAL;
+		if (d.id_len > KVM_VIRT_DEVICE_MAX_ID_LEN)
+			goto out;
+		if (d.flags & ~O_CLOEXEC)
+			goto out;
+		r = -ENOMEM;
+		id = kmalloc(d.id_len, GFP_KERNEL);
+		if (!id)
+			goto out_free_id;
+		r = -EFAULT;
+		if (copy_from_user(id, argp + sizeof d, d.id_len))
+			goto out_free_id;
+		r = virt_device_create(&kvm->hypervisor, d.flags,
+				       id, d.id_len);
+	out_free_id:
+		kfree(id);
+		break;
+	}
 #endif
 	default:
 		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
-- 
1.6.3.1.175.g3be7e0