kvm tools: add generic device registration mechanism

PCI devices are currently registered into the pci_devices array via the
pci__register function, which can then be indexed later by architecture
code to construct device tree nodes. For MMIO devices, there is no such
utility.

Rather than invent a similar mechanism for MMIO, this patch creates a
global device registration mechanism, which allows the device type to be
specified when registered or indexing a device. Current users of the pci
registration code are migrated to the new infrastructure and virtio MMIO
devices are registered at init time.

As part of the device registration, allocation of the device number is
moved out of irq__register_device and performed when adding the device
header to the relevant bus tree, allowing us to maintain separate device
numberspaces for each bus.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

5 files changed, 31 insertions, 3 deletions

diff --git a/include/kvm/devices.h b/include/kvm/devices.h
new file mode 100644
index 00000000..c5de3de2
--- /dev/null
+++ b/include/kvm/devices.h
@@ -0,0 +1,27 @@
+#ifndef KVM__DEVICES_H
+#define KVM__DEVICES_H
+
+#include <linux/rbtree.h>
+#include <linux/types.h>
+
+enum device_bus_type {
+	DEVICE_BUS_PCI,
+	DEVICE_BUS_MMIO,
+	DEVICE_BUS_MAX,
+};
+
+struct device_header {
+	enum device_bus_type	bus_type;
+	void			*data;
+	int			dev_num;
+	struct rb_node		node;
+};
+
+int device__register(struct device_header *dev);
+struct device_header *device__find_dev(enum device_bus_type bus_type,
+				       u8 dev_num);
+
+struct device_header *device__first_dev(enum device_bus_type bus_type);
+struct device_header *device__next_dev(struct device_header *dev);
+
+#endif /* KVM__DEVICES_H */
diff --git a/include/kvm/irq.h b/include/kvm/irq.h
index 43fecaf5..5c1274b9 100644
--- a/include/kvm/irq.h
+++ b/include/kvm/irq.h
@@ -22,7 +22,7 @@ struct pci_dev {
 	struct list_head	lines;
 };
 
-int irq__register_device(u32 dev, u8 *num, u8 *pin, u8 *line);
+int irq__register_device(u32 dev, u8 *pin, u8 *line);
 
 struct rb_node *irq__get_pci_tree(void);
 
diff --git a/include/kvm/pci.h b/include/kvm/pci.h
index 26639b5a..3da38117 100644
--- a/include/kvm/pci.h
+++ b/include/kvm/pci.h
@@ -9,7 +9,6 @@
 #include "kvm/kvm.h"
 #include "kvm/msi.h"
 
-#define PCI_MAX_DEVICES		256
 /*
  * PCI Configuration Mechanism #1 I/O ports. See Section 3.7.4.1.
  * ("Configuration Mechanism #1") of the PCI Local Bus Specification 2.1 for
@@ -86,7 +85,6 @@ struct pci_device_header {
 
 int pci__init(struct kvm *kvm);
 int pci__exit(struct kvm *kvm);
-int pci__register(struct pci_device_header *dev, u8 dev_num);
 struct pci_device_header *pci__find_dev(u8 dev_num);
 u32 pci_get_io_space_block(u32 size);
 void pci__config_wr(struct kvm *kvm, union pci_config_address addr, void *data, int size);
diff --git a/include/kvm/virtio-mmio.h b/include/kvm/virtio-mmio.h
index e0ede3c6..983c8fc1 100644
--- a/include/kvm/virtio-mmio.h
+++ b/include/kvm/virtio-mmio.h
@@ -47,6 +47,7 @@ struct virtio_mmio {
 	struct kvm		*kvm;
 	u8			irq;
 	struct virtio_mmio_hdr	hdr;
+	struct device_header	dev_hdr;
 	struct virtio_mmio_ioevent_param ioeventfds[VIRTIO_MMIO_MAX_VQ];
 };
 
diff --git a/include/kvm/virtio-pci.h b/include/kvm/virtio-pci.h
index 44130e0c..6d9a5586 100644
--- a/include/kvm/virtio-pci.h
+++ b/include/kvm/virtio-pci.h
@@ -1,6 +1,7 @@
 #ifndef KVM__VIRTIO_PCI_H
 #define KVM__VIRTIO_PCI_H
 
+#include "kvm/devices.h"
 #include "kvm/pci.h"
 
 #include <linux/types.h>
@@ -19,6 +20,7 @@ struct virtio_pci_ioevent_param {
 
 struct virtio_pci {
 	struct pci_device_header pci_hdr;
+	struct device_header	dev_hdr;
 	void			*dev;
 
 	u16			base_addr;