Defines | Functions
virtio-pci.c File Reference
#include "errno.h"
#include "byteswap.h"
#include "etherboot.h"
#include "ipxe/io.h"
#include "ipxe/iomap.h"
#include "ipxe/pci.h"
#include "ipxe/reboot.h"
#include "ipxe/virtio-pci.h"
#include "ipxe/virtio-ring.h"

Go to the source code of this file.


#define CFG_POS(vdev, field)   (vdev->cfg_cap_pos + offsetof(struct virtio_pci_cfg_cap, field))


static int vp_alloc_vq (struct vring_virtqueue *vq, u16 num)
void vp_free_vq (struct vring_virtqueue *vq)
int vp_find_vq (unsigned int ioaddr, int queue_index, struct vring_virtqueue *vq)
static void prep_pci_cfg_cap (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, size_t offset, u32 length)
void vpm_iowrite8 (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, u8 data, size_t offset)
void vpm_iowrite16 (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, u16 data, size_t offset)
void vpm_iowrite32 (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, u32 data, size_t offset)
u8 vpm_ioread8 (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, size_t offset)
u16 vpm_ioread16 (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, size_t offset)
u32 vpm_ioread32 (struct virtio_pci_modern_device *vdev, struct virtio_pci_region *region, size_t offset)
int virtio_pci_find_capability (struct pci_device *pci, uint8_t cfg_type)
int virtio_pci_map_capability (struct pci_device *pci, int cap, size_t minlen, u32 align, u32 start, u32 size, struct virtio_pci_region *region)
void virtio_pci_unmap_capability (struct virtio_pci_region *region)
void vpm_notify (struct virtio_pci_modern_device *vdev, struct vring_virtqueue *vq)
int vpm_find_vqs (struct virtio_pci_modern_device *vdev, unsigned nvqs, struct vring_virtqueue *vqs)

Define Documentation

#define CFG_POS (   vdev,
)    (vdev->cfg_cap_pos + offsetof(struct virtio_pci_cfg_cap, field))

Function Documentation

static int vp_alloc_vq ( struct vring_virtqueue vq,
u16  num 
) [static]

Definition at line 24 of file virtio-pci.c.

References ENOMEM, PAGE_MASK, vring_virtqueue::queue, vring_virtqueue::vdata, vring_size, and zalloc().

Referenced by vp_find_vq(), and vpm_find_vqs().

    size_t queue_size = PAGE_MASK + vring_size(num);
    size_t vdata_size = num * sizeof(void *);

    vq->queue = zalloc(queue_size + vdata_size);
    if (!vq->queue) {
        return -ENOMEM;

    /* vdata immediately follows the ring */
    vq->vdata = (void **)(vq->queue + queue_size);

    return 0;
void vp_free_vq ( struct vring_virtqueue vq)

Definition at line 40 of file virtio-pci.c.

References free, NULL, vring_virtqueue::queue, and vring_virtqueue::vdata.

Referenced by virtnet_free_virtqueues().

    if (vq->queue) {
        vq->queue = NULL;
        vq->vdata = NULL;
int vp_find_vq ( unsigned int  ioaddr,
int  queue_index,
struct vring_virtqueue vq 

Definition at line 49 of file virtio-pci.c.

References DBG, vring::desc, inl(), inw(), num, outl(), outw(), PAGE_SHIFT, vring_virtqueue::queue, vring_virtqueue::queue_index, rc, virt_to_phys(), VIRTIO_PCI_QUEUE_NUM, VIRTIO_PCI_QUEUE_PFN, VIRTIO_PCI_QUEUE_SEL, vp_alloc_vq(), vring_virtqueue::vring, and vring_init().

Referenced by virtnet_open_legacy().

   struct vring * vr = &vq->vring;
   u16 num;
   int rc;

   /* select the queue */

   outw(queue_index, ioaddr + VIRTIO_PCI_QUEUE_SEL);

   /* check if the queue is available */

   num = inw(ioaddr + VIRTIO_PCI_QUEUE_NUM);
   if (!num) {
           DBG("VIRTIO-PCI ERROR: queue size is 0\n");
           return -1;

   /* check if the queue is already active */

   if (inl(ioaddr + VIRTIO_PCI_QUEUE_PFN)) {
           DBG("VIRTIO-PCI ERROR: queue already active\n");
           return -1;

   vq->queue_index = queue_index;

   /* initialize the queue */
   rc = vp_alloc_vq(vq, num);
   if (rc) {
           DBG("VIRTIO-PCI ERROR: failed to allocate queue memory\n");
           return rc;
   vring_init(vr, num, vq->queue);

   /* activate the queue
    * NOTE: vr->desc is initialized by vring_init()

   outl((unsigned long)virt_to_phys(vr->desc) >> PAGE_SHIFT,
        ioaddr + VIRTIO_PCI_QUEUE_PFN);

   return num;
static void prep_pci_cfg_cap ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
size_t  offset,
u32  length 
) [static]
void vpm_iowrite8 ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
u8  data,
size_t  offset 
void vpm_iowrite16 ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
u16  data,
size_t  offset 
void vpm_iowrite32 ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
u32  data,
size_t  offset 
u8 vpm_ioread8 ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
size_t  offset 
u16 vpm_ioread16 ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
size_t  offset 
u32 vpm_ioread32 ( struct virtio_pci_modern_device vdev,
struct virtio_pci_region region,
size_t  offset 
int virtio_pci_find_capability ( struct pci_device pci,
uint8_t  cfg_type 

Definition at line 240 of file virtio-pci.c.

References offsetof, PCI_CAP_ID_VNDR, pci_find_capability(), pci_find_next_capability(), pci_read_config_byte(), and type.

Referenced by virtnet_probe_modern().

    int pos;
    uint8_t type, bar;

    for (pos = pci_find_capability(pci, PCI_CAP_ID_VNDR);
         pos > 0;
         pos = pci_find_next_capability(pci, pos, PCI_CAP_ID_VNDR)) {

        pci_read_config_byte(pci, pos + offsetof(struct virtio_pci_cap,
            cfg_type), &type);
        pci_read_config_byte(pci, pos + offsetof(struct virtio_pci_cap,
            bar), &bar);

        /* Ignore structures with reserved BAR values */
        if (bar > 0x5) {

        if (type == cfg_type) {
            return pos;
    return 0;
int virtio_pci_map_capability ( struct pci_device pci,
int  cap,
size_t  minlen,
u32  align,
u32  start,
u32  size,
struct virtio_pci_region region 

Definition at line 266 of file virtio-pci.c.

References virtio_pci_region::bar, base, virtio_pci_region::base, DBG, EINVAL, virtio_pci_region::flags, ioremap(), length, virtio_pci_region::length, NULL, offset, offsetof, pci_bar_size(), pci_bar_start(), PCI_BASE_ADDRESS, PCI_BASE_ADDRESS_SPACE_IO, pci_read_config_byte(), pci_read_config_dword(), size, start, VIRTIO_PCI_REGION_MEMORY, VIRTIO_PCI_REGION_PCI_CONFIG, and VIRTIO_PCI_REGION_PORT.

Referenced by virtnet_probe_modern(), and vpm_find_vqs().

    u8 bar;
    u32 offset, length, base_raw;
    unsigned long base;

    pci_read_config_byte(pci, cap + offsetof(struct virtio_pci_cap, bar), &bar);
    pci_read_config_dword(pci, cap + offsetof(struct virtio_pci_cap, offset),
    pci_read_config_dword(pci, cap + offsetof(struct virtio_pci_cap, length),

    if (length <= start) {
        DBG("VIRTIO-PCI bad capability len %d (>%d expected)\n", length, start);
        return -EINVAL;
    if (length - start < minlen) {
        DBG("VIRTIO-PCI bad capability len %d (>=%zd expected)\n", length, minlen);
        return -EINVAL;
    length -= start;
    if (start + offset < offset) {
        DBG("VIRTIO-PCI map wrap-around %d+%d\n", start, offset);
        return -EINVAL;
    offset += start;
    if (offset & (align - 1)) {
        DBG("VIRTIO-PCI offset %d not aligned to %d\n", offset, align);
        return -EINVAL;
    if (length > size) {
        length = size;

    if (minlen + offset < minlen ||
        minlen + offset > pci_bar_size(pci, PCI_BASE_ADDRESS(bar))) {
        DBG("VIRTIO-PCI map virtio %zd@%d out of range on bar %i length %ld\n",
            minlen, offset,
            bar, pci_bar_size(pci, PCI_BASE_ADDRESS(bar)));
        return -EINVAL;

    region->base = NULL;
    region->length = length;
    region->bar = bar;

    base = pci_bar_start(pci, PCI_BASE_ADDRESS(bar));
    if (base) {
        pci_read_config_dword(pci, PCI_BASE_ADDRESS(bar), &base_raw);

        if (base_raw & PCI_BASE_ADDRESS_SPACE_IO) {
            /* Region accessed using port I/O */
            region->base = (void *)(base + offset);
            region->flags = VIRTIO_PCI_REGION_PORT;
        } else {
            /* Region mapped into memory space */
            region->base = ioremap(base + offset, length);
            region->flags = VIRTIO_PCI_REGION_MEMORY;
    if (!region->base) {
        /* Region accessed via PCI config space window */
            region->base = (void *)(intptr_t)offset;
        region->flags = VIRTIO_PCI_REGION_PCI_CONFIG;
    return 0;
void vpm_notify ( struct virtio_pci_modern_device vdev,
struct vring_virtqueue vq 

Definition at line 344 of file virtio-pci.c.

References vring_virtqueue::notification, vring_virtqueue::queue_index, and vpm_iowrite16().

Referenced by vring_kick().

    vpm_iowrite16(vdev, &vq->notification, (u16)vq->queue_index, 0);
int vpm_find_vqs ( struct virtio_pci_modern_device vdev,
unsigned  nvqs,
struct vring_virtqueue vqs 

Definition at line 350 of file virtio-pci.c.

References vring::avail, virtio_pci_modern_device::common, COMMON_OFFSET, DBG, vring::desc, EINVAL, ENOENT, MAX_QUEUE_NUM, vring_virtqueue::notification, virtio_pci_modern_device::notify_cap_pos, offsetof, virtio_pci_modern_device::pci, pci_read_config_dword(), vring_virtqueue::queue, vring_virtqueue::queue_index, size, vring::used, virt_to_phys(), virtio_pci_map_capability(), vp_alloc_vq(), vpm_ioread16(), vpm_iowrite16(), vpm_iowrite64(), vring_virtqueue::vring, and vring_init().

Referenced by virtnet_open_modern().

    unsigned i;
    struct vring_virtqueue *vq;
    u16 size, off;
    u32 notify_offset_multiplier;
    int err;

    if (nvqs > vpm_ioread16(vdev, &vdev->common, COMMON_OFFSET(num_queues))) {
        return -ENOENT;

    /* Read notify_off_multiplier from config space. */
        vdev->notify_cap_pos + offsetof(struct virtio_pci_notify_cap,

    for (i = 0; i < nvqs; i++) {
        /* Select the queue we're interested in */
        vpm_iowrite16(vdev, &vdev->common, (u16)i, COMMON_OFFSET(queue_select));

        /* Check if queue is either not available or already active. */
        size = vpm_ioread16(vdev, &vdev->common, COMMON_OFFSET(queue_size));
        /* QEMU has a bug where queues don't revert to inactive on device
         * reset. Skip checking the queue_enable field until it is fixed.
        if (!size /*|| vpm_ioread16(vdev, &vdev->common.queue_enable)*/)
            return -ENOENT;

        if (size & (size - 1)) {
            DBG("VIRTIO-PCI %p: bad queue size %d\n", vdev, size);
            return -EINVAL;

        if (size > MAX_QUEUE_NUM) {
            /* iPXE networking tends to be not perf critical so there's no
             * need to accept large queue sizes.
            size = MAX_QUEUE_NUM;

        vq = &vqs[i];
        vq->queue_index = i;

        /* get offset of notification word for this vq */
        off = vpm_ioread16(vdev, &vdev->common, COMMON_OFFSET(queue_notify_off));

        err = vp_alloc_vq(vq, size);
        if (err) {
            DBG("VIRTIO-PCI %p: failed to allocate queue memory\n", vdev);
            return err;
        vring_init(&vq->vring, size, vq->queue);

        /* activate the queue */
        vpm_iowrite16(vdev, &vdev->common, size, COMMON_OFFSET(queue_size));

        vpm_iowrite64(vdev, &vdev->common, virt_to_phys(vq->vring.desc),
        vpm_iowrite64(vdev, &vdev->common, virt_to_phys(vq->vring.avail),
        vpm_iowrite64(vdev, &vdev->common, virt_to_phys(vq->vring.used),

        err = virtio_pci_map_capability(vdev->pci,
            vdev->notify_cap_pos, 2, 2,
            off * notify_offset_multiplier, 2,
        if (err) {
            return err;

    /* Select and activate all queues. Has to be done last: once we do
     * this, there's no way to go back except reset.
    for (i = 0; i < nvqs; i++) {
        vq = &vqs[i];
        vpm_iowrite16(vdev, &vdev->common, (u16)vq->queue_index,
        vpm_iowrite16(vdev, &vdev->common, 1, COMMON_OFFSET(queue_enable));
    return 0;