xref: /kvmtool/virtio/rng.c (revision 407475bf94de5be1e8057c919cfa4af1900b7025)

#include "kvm/virtio-rng.h"

#include "kvm/virtio-pci.h"

#include "kvm/disk-image.h"
#include "kvm/virtio.h"
#include "kvm/ioport.h"
#include "kvm/mutex.h"
#include "kvm/util.h"
#include "kvm/kvm.h"
#include "kvm/pci.h"
#include "kvm/threadpool.h"

#include <linux/virtio_ring.h>
#include <linux/virtio_rng.h>

#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <pthread.h>

#define PCI_VENDOR_ID_REDHAT_QUMRANET		0x1af4
#define PCI_DEVICE_ID_VIRTIO_RNG		0x1004
#define PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET	0x1af4
#define PCI_SUBSYSTEM_ID_VIRTIO_RNG		0x0004
#define PCI_VIRTIO_RNG_DEVNUM			4

#define VIRTIO_RNG_IRQ				11
#define VIRTIO_RNG_PIN				1

#define NUM_VIRT_QUEUES				1
#define VIRTIO_RNG_QUEUE_SIZE			128

struct rng_dev {
	u8					status;
	u16					config_vector;
	int					fd;

	/* virtio queue */
	u16					queue_selector;
	struct virt_queue			vqs[NUM_VIRT_QUEUES];
	void					*jobs[NUM_VIRT_QUEUES];
};

static struct rng_dev rdev;

static bool virtio_rng_pci_io_in(struct kvm *kvm, u16 port, void *data, int size, u32 count)
{
	unsigned long offset;
	bool ret = true;

	offset = port - IOPORT_VIRTIO_RNG;

	switch (offset) {
	case VIRTIO_PCI_HOST_FEATURES:
	case VIRTIO_PCI_GUEST_FEATURES:
	case VIRTIO_PCI_QUEUE_SEL:
	case VIRTIO_PCI_QUEUE_NOTIFY:
		ret		= false;
		break;
	case VIRTIO_PCI_QUEUE_PFN:
		ioport__write32(data, rdev.vqs[rdev.queue_selector].pfn);
		break;
	case VIRTIO_PCI_QUEUE_NUM:
		ioport__write16(data, VIRTIO_RNG_QUEUE_SIZE);
		break;
	case VIRTIO_PCI_STATUS:
		ioport__write8(data, rdev.status);
		break;
	case VIRTIO_PCI_ISR:
		ioport__write8(data, 0x1);
		kvm__irq_line(kvm, VIRTIO_RNG_IRQ, 0);
		break;
	case VIRTIO_MSI_CONFIG_VECTOR:
		ioport__write16(data, rdev.config_vector);
		break;
	default:
		ret		= false;
		break;
	};

	return ret;
}

static bool virtio_rng_do_io_request(struct kvm *kvm, struct virt_queue *queue)
{
	struct iovec iov[VIRTIO_RNG_QUEUE_SIZE];
	unsigned int len = 0;
	u16 out, in, head;

	head		= virt_queue__get_iov(queue, iov, &out, &in, kvm);
	len		= readv(rdev.fd, iov, in);

	virt_queue__set_used_elem(queue, head, len);

	return true;
}

static void virtio_rng_do_io(struct kvm *kvm, void *param)
{
	struct virt_queue *vq = param;

	while (virt_queue__available(vq)) {
		virtio_rng_do_io_request(kvm, vq);
		kvm__irq_line(kvm, VIRTIO_RNG_IRQ, 1);
	}
}

static bool virtio_rng_pci_io_out(struct kvm *kvm, u16 port, void *data, int size, u32 count)
{
	unsigned long offset;
	bool ret = true;

	offset		= port - IOPORT_VIRTIO_RNG;

	switch (offset) {
	case VIRTIO_MSI_QUEUE_VECTOR:
	case VIRTIO_PCI_GUEST_FEATURES:
		break;
	case VIRTIO_PCI_QUEUE_PFN: {
		struct virt_queue *queue;
		void *p;

		queue			= &rdev.vqs[rdev.queue_selector];
		queue->pfn		= ioport__read32(data);
		p			= guest_flat_to_host(kvm, queue->pfn << 12);

		vring_init(&queue->vring, VIRTIO_RNG_QUEUE_SIZE, p, 4096);

		rdev.jobs[rdev.queue_selector] = thread_pool__add_job(kvm, virtio_rng_do_io, queue);

		break;
	}
	case VIRTIO_PCI_QUEUE_SEL:
		rdev.queue_selector	= ioport__read16(data);
		break;
	case VIRTIO_PCI_QUEUE_NOTIFY: {
		u16 queue_index;
		queue_index		= ioport__read16(data);
		thread_pool__do_job(rdev.jobs[queue_index]);
		break;
	}
	case VIRTIO_PCI_STATUS:
		rdev.status		= ioport__read8(data);
		break;
	case VIRTIO_MSI_CONFIG_VECTOR:
		rdev.config_vector	= VIRTIO_MSI_NO_VECTOR;
		break;
	default:
		ret			= false;
		break;
	};

	return ret;
}

static struct ioport_operations virtio_rng_io_ops = {
	.io_in				= virtio_rng_pci_io_in,
	.io_out				= virtio_rng_pci_io_out,
};

static struct pci_device_header virtio_rng_pci_device = {
	.vendor_id			= PCI_VENDOR_ID_REDHAT_QUMRANET,
	.device_id			= PCI_DEVICE_ID_VIRTIO_RNG,
	.header_type			= PCI_HEADER_TYPE_NORMAL,
	.revision_id			= 0,
	.class				= 0x010000,
	.subsys_vendor_id		= PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET,
	.subsys_id			= PCI_SUBSYSTEM_ID_VIRTIO_RNG,
	.bar[0]				= IOPORT_VIRTIO_RNG | PCI_BASE_ADDRESS_SPACE_IO,
	.irq_pin			= VIRTIO_RNG_PIN,
	.irq_line			= VIRTIO_RNG_IRQ,
};

void virtio_rng__init(struct kvm *kvm)
{
	rdev.fd = open("/dev/urandom", O_RDONLY);
	if (rdev.fd < 0)
		die("Failed initializing RNG");

	pci__register(&virtio_rng_pci_device, PCI_VIRTIO_RNG_DEVNUM);

	ioport__register(IOPORT_VIRTIO_RNG, &virtio_rng_io_ops, IOPORT_VIRTIO_RNG_SIZE);
}