Re: [PATCH] [PATCH 1/3] virtio infrastructure

[Dor Laor <dor.laor-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Anthony Liguori wrote:
> Dor Laor wrote:
>> Anthony Liguori wrote:
>>  
>>> Hi Dor,
>>>
>>> I can't tell if you made any changes to this series.  I have to look 
>>> back to my notes, but I believe it would be okay to pull this series 
>>> into KVM.  I still need to spend some time updating the patchset to 
>>> be more friendly for QEMU though before resubmitting to qemu-devel.  
>>> Any help on making it more cross-architecture friendly would be 
>>> appreciated!
>>>
>>>     
>> Hi,
>>
>> I didn't do any change (except maybe very very minor adjustments for 
>> it to match existing version, nothing risky).
>> The reason I sent it as it is + non-qemu-standard performance 
>> optimization is to finally have descent performance for KVM IO.
>> My next step is to add backward compatibility support for older 
>> guests and then to implement host kernel module for network.
>>   
>
> I have backports up to 2.6.18 although I need to write the awk scripts 
> to make it automatic.  If you can wait until the middle of the week 
> when I get back into the office, I'll post it.
>
> Regards,
>
> Anthony Liguori
>
Superb, I'll happily wait.
>> I hope that someone will pick up the qemu part since it's important 
>> too, especially the block device and new devices too.
>> There is also work in progress to move the balloon driver over virtio.
>> Thanks,
>> Dor.
>>  
>>> Regards,
>>>
>>> Anthony Liguori
>>>
>>> Dor.Laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org wrote:
>>>    
>>>> From: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
>>>>
>>>> This patch implements the basic infrastructure for virtio devices.  
>>>> These
>>>> devices are exposed to the guest as real PCI devices.  The PCI 
>>>> vendor/device
>>>> IDs have been donated by Qumranet and the subsystem IDs are used to 
>>>> distinguish
>>>> the virtio device itself.
>>>>
>>>> Virtio provides an abstraction for performing guest=>host and 
>>>> host=>guest
>>>> communications.  It also provides a standard ring queue interface 
>>>> and discovery
>>>> mechanism.  Finally, virtio provides a simple mechanism for passing
>>>> configuration between host and guest.
>>>>
>>>> In this virtio implementation, we provide these things via normal PCI
>>>> operations.  The Linux kernel support for this virtio device is 
>>>> pending in
>>>> Rusty's virtio patch queue[1].  They should be submitted once the 
>>>> merge window
>>>> opens again.
>>>>
>>>> Some future TODOs are to use endian/alignment safe routines when 
>>>> accessing the
>>>> virtqueue so that mixed mode host/guests are supported.
>>>>
>>>> [1] http://ozlabs.org/~rusty/kernel/hg
>>>>
>>>> Signed-off-by: Anthony Liguori <aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
>>>> Cc: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
>>>> Cc: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
>>>> Cc: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
>>>> ---
>>>>  qemu/Makefile.target |    3 +
>>>>  qemu/hw/virtio.c     |  422 
>>>> ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>  qemu/hw/virtio.h     |  143 +++++++++++++++++
>>>>  3 files changed, 568 insertions(+), 0 deletions(-)
>>>>  create mode 100644 qemu/hw/virtio.c
>>>>  create mode 100644 qemu/hw/virtio.h
>>>>
>>>> diff --git a/qemu/Makefile.target b/qemu/Makefile.target
>>>> index 12fb043..8b5853b 100644
>>>> --- a/qemu/Makefile.target
>>>> +++ b/qemu/Makefile.target
>>>> @@ -463,6 +463,9 @@ VL_OBJS += rtl8139.o
>>>>  # PCI Hypercall
>>>>  VL_OBJS+= hypercall.o
>>>>
>>>> +# virtio devices
>>>> +VL_OBJS += virtio.o
>>>> +
>>>>  ifeq ($(TARGET_BASE_ARCH), i386)
>>>>  # Hardware support
>>>>  VL_OBJS+= ide.o pckbd.o ps2.o vga.o $(SOUND_HW) dma.o
>>>> diff --git a/qemu/hw/virtio.c b/qemu/hw/virtio.c
>>>> new file mode 100644
>>>> index 0000000..6a1d380
>>>> --- /dev/null
>>>> +++ b/qemu/hw/virtio.c
>>>> @@ -0,0 +1,422 @@
>>>> +/*
>>>> + * Virtio Support
>>>> + *
>>>> + * Copyright IBM, Corp. 2007
>>>> + *
>>>> + * Authors:
>>>> + *  Anthony Liguori   <aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
>>>> + *
>>>> + * This work is licensed under the terms of the GNU GPL, version 
>>>> 2.  See
>>>> + * the COPYING file in the top-level directory.
>>>> + *
>>>> + */
>>>> +
>>>> +#include <inttypes.h>
>>>> +#include <err.h>
>>>> +
>>>> +#include "virtio.h"
>>>> +#include "sysemu.h"
>>>> +
>>>> +/* from Linux's linux/virtio_pci.h */
>>>> +
>>>> +/* A 32-bit r/o bitmask of the features supported by the host */
>>>> +#define VIRTIO_PCI_HOST_FEATURES    0
>>>> +
>>>> +/* A 32-bit r/w bitmask of features activated by the guest */
>>>> +#define VIRTIO_PCI_GUEST_FEATURES    4
>>>> +
>>>> +/* A 32-bit r/w PFN for the currently selected queue */
>>>> +#define VIRTIO_PCI_QUEUE_PFN        8
>>>> +
>>>> +/* A 16-bit r/o queue size for the currently selected queue */
>>>> +#define VIRTIO_PCI_QUEUE_NUM        12
>>>> +
>>>> +/* A 16-bit r/w queue selector */
>>>> +#define VIRTIO_PCI_QUEUE_SEL        14
>>>> +
>>>> +/* A 16-bit r/w queue notifier */
>>>> +#define VIRTIO_PCI_QUEUE_NOTIFY        16
>>>> +
>>>> +/* An 8-bit device status register.  */
>>>> +#define VIRTIO_PCI_STATUS        18
>>>> +
>>>> +/* An 8-bit r/o interrupt status register.  Reading the value will 
>>>> return the
>>>> + * current contents of the ISR and will also clear it.  This is 
>>>> effectively
>>>> + * a read-and-acknowledge. */
>>>> +#define VIRTIO_PCI_ISR            19
>>>> +
>>>> +#define VIRTIO_PCI_CONFIG        20
>>>> +
>>>> +/* QEMU doesn't strictly need write barriers since everything runs in
>>>> + * lock-step.  We'll leave the calls to wmb() in though to make it 
>>>> obvious for
>>>> + * KVM or if kqemu gets SMP support.
>>>> + */
>>>> +#define wmb() do { } while (0)
>>>> +
>>>> +/* virt queue functions */
>>>> +
>>>> +static void virtqueue_init(VirtQueue *vq, void *p)
>>>> +{
>>>> +    vq->vring.desc = p;
>>>> +    vq->vring.avail = p + vq->vring.num * sizeof(VRingDesc);
>>>> +    vq->vring.used = (void *)TARGET_PAGE_ALIGN((unsigned 
>>>> long)&vq->vring.avail->ring[vq->vring.num]);
>>>> +}
>>>> +
>>>> +static unsigned virtqueue_next_desc(VirtQueue *vq, unsigned int i)
>>>> +{
>>>> +    unsigned int next;
>>>> +
>>>> +    /* If this descriptor says it doesn't chain, we're done. */
>>>> +    if (!(vq->vring.desc[i].flags & VRING_DESC_F_NEXT))
>>>> +    return vq->vring.num;
>>>> +
>>>> +    /* Check they're not leading us off end of descriptors. */
>>>> +    next = vq->vring.desc[i].next;
>>>> +    /* Make sure compiler knows to grab that: we don't want it 
>>>> changing! */
>>>> +    wmb();
>>>> +
>>>> +    if (next >= vq->vring.num)
>>>> +    errx(1, "Desc next is %u", next);
>>>> +
>>>> +    return next;
>>>> +}
>>>> +
>>>> +void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
>>>> +            unsigned int len)
>>>> +{
>>>> +    VRingUsedElem *used;
>>>> +
>>>> +    /* Get a pointer to the next entry in the used ring. */
>>>> +    used = &vq->vring.used->ring[vq->vring.used->idx % 
>>>> vq->vring.num];
>>>> +    used->id = elem->index;
>>>> +    used->len = len;
>>>> +    /* Make sure buffer is written before we update index. */
>>>> +    wmb();
>>>> +    vq->vring.used->idx++;
>>>> +}
>>>> +
>>>> +int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
>>>> +{
>>>> +    unsigned int i, head;
>>>> +    unsigned int position;
>>>> +
>>>> +    /* Check it isn't doing very strange things with descriptor 
>>>> numbers. */
>>>> +    if ((uint16_t)(vq->vring.avail->idx - vq->last_avail_idx) > 
>>>> vq->vring.num)
>>>> +    errx(1, "Guest moved used index from %u to %u",
>>>> +         vq->last_avail_idx, vq->vring.avail->idx);
>>>> +
>>>> +    /* If there's nothing new since last we looked, return 
>>>> invalid. */
>>>> +    if (vq->vring.avail->idx == vq->last_avail_idx)
>>>> +    return 0;
>>>> +
>>>> +    /* Grab the next descriptor number they're advertising, and 
>>>> increment
>>>> +     * the index we've seen. */
>>>> +    head = vq->vring.avail->ring[vq->last_avail_idx++ % 
>>>> vq->vring.num];
>>>> +
>>>> +    /* If their number is silly, that's a fatal mistake. */
>>>> +    if (head >= vq->vring.num)
>>>> +    errx(1, "Guest says index %u is available", head);
>>>> +
>>>> +    /* When we start there are none of either input nor output. */
>>>> +    position = elem->out_num = elem->in_num = 0;
>>>> +
>>>> +    i = head;
>>>> +    do {
>>>> +    struct iovec *sg;
>>>> +
>>>> +    if ((vq->vring.desc[i].addr + vq->vring.desc[i].len) > ram_size)
>>>> +        errx(1, "Guest sent invalid pointer");
>>>> +
>>>> +    if (vq->vring.desc[i].flags & VRING_DESC_F_WRITE)
>>>> +        sg = &elem->in_sg[elem->in_num++];
>>>> +    else
>>>> +        sg = &elem->out_sg[elem->out_num++];
>>>> +
>>>> +    /* Grab the first descriptor, and check it's OK. */
>>>> +    sg->iov_len = vq->vring.desc[i].len;
>>>> +    sg->iov_base = phys_ram_base + vq->vring.desc[i].addr;
>>>> +
>>>> +    /* If we've got too many, that implies a descriptor loop. */
>>>> +    if ((elem->in_num + elem->out_num) > vq->vring.num)
>>>> +        errx(1, "Looped descriptor");
>>>> +    } while ((i = virtqueue_next_desc(vq, i)) != vq->vring.num);
>>>> +
>>>> +    elem->index = head;
>>>> +
>>>> +    return elem->in_num + elem->out_num;
>>>> +}
>>>> +
>>>> +/* virtio device */
>>>> +
>>>> +static VirtIODevice *to_virtio_device(PCIDevice *pci_dev)
>>>> +{
>>>> +    return (VirtIODevice *)pci_dev;
>>>> +}
>>>> +
>>>> +static void virtio_update_irq(VirtIODevice *vdev)
>>>> +{
>>>> +    qemu_set_irq(vdev->pci_dev.irq[0], vdev->isr & 1);
>>>> +}
>>>> +
>>>> +static void virtio_ioport_write(void *opaque, uint32_t addr, 
>>>> uint32_t val)
>>>> +{
>>>> +    VirtIODevice *vdev = to_virtio_device(opaque);
>>>> +    ram_addr_t pa;
>>>> +
>>>> +    addr -= vdev->addr;
>>>> +
>>>> +    switch (addr) {
>>>> +    case VIRTIO_PCI_GUEST_FEATURES:
>>>> +    if (vdev->set_features)
>>>> +        vdev->set_features(vdev, val);
>>>> +    vdev->features = val;
>>>> +    break;
>>>> +    case VIRTIO_PCI_QUEUE_PFN:
>>>> +    pa = (ram_addr_t)val << TARGET_PAGE_BITS;
>>>> +    vdev->vq[vdev->queue_sel].pfn = val;
>>>> +    if (pa == 0) {
>>>> +        vdev->vq[vdev->queue_sel].vring.desc = NULL;
>>>> +        vdev->vq[vdev->queue_sel].vring.avail = NULL;
>>>> +        vdev->vq[vdev->queue_sel].vring.used = NULL;
>>>> +    } else if (pa < (ram_size - TARGET_PAGE_SIZE)) {
>>>> +        virtqueue_init(&vdev->vq[vdev->queue_sel], phys_ram_base + 
>>>> pa);
>>>> +        /* FIXME if pa == 0, deal with device tear down */
>>>> +    }
>>>> +    break;
>>>> +    case VIRTIO_PCI_QUEUE_SEL:
>>>> +    if (val < VIRTIO_PCI_QUEUE_MAX)
>>>> +        vdev->queue_sel = val;
>>>> +    break;
>>>> +    case VIRTIO_PCI_QUEUE_NOTIFY:
>>>> +    if (val < VIRTIO_PCI_QUEUE_MAX && vdev->vq[val].vring.desc)
>>>> +        vdev->vq[val].handle_output(vdev, &vdev->vq[val]);
>>>> +    break;
>>>> +    case VIRTIO_PCI_STATUS:
>>>> +    vdev->status = val & 0xFF;
>>>> +    break;
>>>> +    }
>>>> +}
>>>> +
>>>> +static uint32_t virtio_ioport_read(void *opaque, uint32_t addr)
>>>> +{
>>>> +    VirtIODevice *vdev = to_virtio_device(opaque);
>>>> +    uint32_t ret = 0xFFFFFFFF;
>>>> +
>>>> +    addr -= vdev->addr;
>>>> +
>>>> +    switch (addr) {
>>>> +    case VIRTIO_PCI_HOST_FEATURES:
>>>> +    ret = vdev->get_features(vdev);
>>>> +    break;
>>>> +    case VIRTIO_PCI_GUEST_FEATURES:
>>>> +    ret = vdev->features;
>>>> +    break;
>>>> +    case VIRTIO_PCI_QUEUE_PFN:
>>>> +    ret = vdev->vq[vdev->queue_sel].pfn;
>>>> +    break;
>>>> +    case VIRTIO_PCI_QUEUE_NUM:
>>>> +    ret = vdev->vq[vdev->queue_sel].vring.num;
>>>> +    break;
>>>> +    case VIRTIO_PCI_QUEUE_SEL:
>>>> +    ret = vdev->queue_sel;
>>>> +    break;
>>>> +    case VIRTIO_PCI_STATUS:
>>>> +    ret = vdev->status;
>>>> +    break;
>>>> +    case VIRTIO_PCI_ISR:
>>>> +    /* reading from the ISR also clears it. */
>>>> +    ret = vdev->isr;
>>>> +    vdev->isr = 0;
>>>> +    virtio_update_irq(vdev);
>>>> +    break;
>>>> +    default:
>>>> +    break;
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static uint32_t virtio_config_readb(void *opaque, uint32_t addr)
>>>> +{
>>>> +    VirtIODevice *vdev = opaque;
>>>> +    uint8_t val;
>>>> +
>>>> +    addr -= vdev->addr + VIRTIO_PCI_CONFIG;
>>>> +    if (addr > (vdev->config_len - sizeof(val)))
>>>> +    return (uint32_t)-1;
>>>> +
>>>> +    memcpy(&val, vdev->config + addr, sizeof(val));
>>>> +    return val;
>>>> +}
>>>> +
>>>> +static uint32_t virtio_config_readw(void *opaque, uint32_t addr)
>>>> +{
>>>> +    VirtIODevice *vdev = opaque;
>>>> +    uint16_t val;
>>>> +
>>>> +    addr -= vdev->addr + VIRTIO_PCI_CONFIG;
>>>> +    if (addr > (vdev->config_len - sizeof(val)))
>>>> +    return (uint32_t)-1;
>>>> +
>>>> +    memcpy(&val, vdev->config + addr, sizeof(val));
>>>> +    return val;
>>>> +}
>>>> +
>>>> +static uint32_t virtio_config_readl(void *opaque, uint32_t addr)
>>>> +{
>>>> +    VirtIODevice *vdev = opaque;
>>>> +    uint32_t val;
>>>> +
>>>> +    addr -= vdev->addr + VIRTIO_PCI_CONFIG;
>>>> +    if (addr > (vdev->config_len - sizeof(val)))
>>>> +    return (uint32_t)-1;
>>>> +
>>>> +    memcpy(&val, vdev->config + addr, sizeof(val));
>>>> +    return val;
>>>> +}
>>>> +
>>>> +static void virtio_config_writeb(void *opaque, uint32_t addr, 
>>>> uint32_t data)
>>>> +{
>>>> +    VirtIODevice *vdev = opaque;
>>>> +    uint8_t val = data;
>>>> +
>>>> +    addr -= vdev->addr + VIRTIO_PCI_CONFIG;
>>>> +    if (addr > (vdev->config_len - sizeof(val)))
>>>> +    return;
>>>> +
>>>> +    memcpy(vdev->config + addr, &val, sizeof(val));
>>>> +}
>>>> +
>>>> +static void virtio_config_writew(void *opaque, uint32_t addr, 
>>>> uint32_t data)
>>>> +{
>>>> +    VirtIODevice *vdev = opaque;
>>>> +    uint16_t val = data;
>>>> +
>>>> +    addr -= vdev->addr + VIRTIO_PCI_CONFIG;
>>>> +    if (addr > (vdev->config_len - sizeof(val)))
>>>> +    return;
>>>> +
>>>> +    memcpy(vdev->config + addr, &val, sizeof(val));
>>>> +}
>>>> +
>>>> +static void virtio_config_writel(void *opaque, uint32_t addr, 
>>>> uint32_t data)
>>>> +{
>>>> +    VirtIODevice *vdev = opaque;
>>>> +    uint32_t val = data;
>>>> +
>>>> +    addr -= vdev->addr + VIRTIO_PCI_CONFIG;
>>>> +    if (addr > (vdev->config_len - sizeof(val)))
>>>> +    return;
>>>> +
>>>> +    memcpy(vdev->config + addr, &val, sizeof(val));
>>>> +}
>>>> +
>>>> +static void virtio_map(PCIDevice *pci_dev, int region_num,
>>>> +               uint32_t addr, uint32_t size, int type)
>>>> +{
>>>> +    VirtIODevice *vdev = to_virtio_device(pci_dev);
>>>> +    int i;
>>>> +
>>>> +    vdev->addr = addr;
>>>> +    for (i = 0; i < 3; i++) {
>>>> +    register_ioport_write(addr, 20, 1 << i, virtio_ioport_write, 
>>>> vdev);
>>>> +    register_ioport_read(addr, 20, 1 << i, virtio_ioport_read, vdev);
>>>> +    }
>>>> +
>>>> +    if (vdev->config_len) {
>>>> +    register_ioport_write(addr + 20, vdev->config_len, 1,
>>>> +                  virtio_config_writeb, vdev);
>>>> +    register_ioport_write(addr + 20, vdev->config_len, 2,
>>>> +                  virtio_config_writew, vdev);
>>>> +    register_ioport_write(addr + 20, vdev->config_len, 4,
>>>> +                  virtio_config_writel, vdev);
>>>> +    register_ioport_read(addr + 20, vdev->config_len, 1,
>>>> +                 virtio_config_readb, vdev);
>>>> +    register_ioport_read(addr + 20, vdev->config_len, 2,
>>>> +                 virtio_config_readw, vdev);
>>>> +    register_ioport_read(addr + 20, vdev->config_len, 4,
>>>> +                 virtio_config_readl, vdev);
>>>> +
>>>> +    vdev->update_config(vdev, vdev->config);
>>>> +    }
>>>> +}
>>>> +
>>>> +VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
>>>> +                void (*handle_output)(VirtIODevice *, VirtQueue *))
>>>> +{
>>>> +    int i;
>>>> +
>>>> +    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
>>>> +    if (vdev->vq[i].vring.num == 0)
>>>> +        break;
>>>> +    }
>>>> +
>>>> +    if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
>>>> +    abort();
>>>> +
>>>> +    vdev->vq[i].vring.num = queue_size;
>>>> +    vdev->vq[i].handle_output = handle_output;
>>>> +    vdev->vq[i].index = i;
>>>> +
>>>> +    return &vdev->vq[i];
>>>> +}
>>>> +
>>>> +void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
>>>> +{
>>>> +    if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
>>>> +    return;
>>>> +
>>>> +    vdev->isr = 1;
>>>> +    virtio_update_irq(vdev);
>>>> +}
>>>> +
>>>> +VirtIODevice *virtio_init_pci(PCIBus *bus, const char *name,
>>>> +                  uint16_t vendor, uint16_t device,
>>>> +                  uint16_t subvendor, uint16_t subdevice,
>>>> +                  uint8_t class_code, uint8_t subclass_code,
>>>> +                  uint8_t pif, size_t config_size,
>>>> +                  size_t struct_size)
>>>> +{
>>>> +    VirtIODevice *vdev;
>>>> +    PCIDevice *pci_dev;
>>>> +    uint8_t *config;
>>>> +
>>>> +    pci_dev = pci_register_device(bus, name, struct_size,
>>>> +                  -1, NULL, NULL);
>>>> +    vdev = to_virtio_device(pci_dev);
>>>> +
>>>> +    vdev->status = 0;
>>>> +    vdev->isr = 0;
>>>> +    vdev->queue_sel = 0;
>>>> +    memset(vdev->vq, 0, sizeof(vdev->vq));
>>>> +
>>>> +    config = pci_dev->config;
>>>> +    config[0x00] = vendor & 0xFF;
>>>> +    config[0x01] = (vendor >> 8) & 0xFF;
>>>> +    config[0x02] = device & 0xFF;
>>>> +    config[0x03] = (device >> 8) & 0xFF;
>>>> +
>>>> +    config[0x09] = pif;
>>>> +    config[0x0a] = subclass_code;
>>>> +    config[0x0b] = class_code;
>>>> +    config[0x0e] = 0x00;
>>>> +
>>>> +    config[0x2c] = subvendor & 0xFF;
>>>> +    config[0x2d] = (subvendor >> 8) & 0xFF;
>>>> +    config[0x2e] = subdevice & 0xFF;
>>>> +    config[0x2f] = (subdevice >> 8) & 0xFF;
>>>> +
>>>> +    config[0x3d] = 1;
>>>> +
>>>> +    vdev->name = name;
>>>> +    vdev->config_len = config_size;
>>>> +    if (vdev->config_len)
>>>> +    vdev->config = qemu_mallocz(config_size);
>>>> +    else
>>>> +    vdev->config = NULL;
>>>> +
>>>> +    pci_register_io_region(pci_dev, 0, 20 + config_size, 
>>>> PCI_ADDRESS_SPACE_IO,
>>>> +               virtio_map);
>>>> +
>>>> +    return vdev;
>>>> +}
>>>> diff --git a/qemu/hw/virtio.h b/qemu/hw/virtio.h
>>>> new file mode 100644
>>>> index 0000000..dee97ba
>>>> --- /dev/null
>>>> +++ b/qemu/hw/virtio.h
>>>> @@ -0,0 +1,143 @@
>>>> +/*
>>>> + * Virtio Support
>>>> + *
>>>> + * Copyright IBM, Corp. 2007
>>>> + *
>>>> + * Authors:
>>>> + *  Anthony Liguori   <aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
>>>> + *
>>>> + * This work is licensed under the terms of the GNU GPL, version 
>>>> 2.  See
>>>> + * the COPYING file in the top-level directory.
>>>> + *
>>>> + */
>>>> +
>>>> +#ifndef _QEMU_VIRTIO_H
>>>> +#define _QEMU_VIRTIO_H
>>>> +
>>>> +#include <sys/uio.h>
>>>> +#include "hw.h"
>>>> +#include "pci.h"
>>>> +
>>>> +/* from Linux's linux/virtio_config.h */
>>>> +
>>>> +/* Status byte for guest to report progress, and synchronize 
>>>> features. */
>>>> +/* We have seen device and processed generic fields 
>>>> (VIRTIO_CONFIG_F_VIRTIO) */
>>>> +#define VIRTIO_CONFIG_S_ACKNOWLEDGE    1
>>>> +/* We have found a driver for the device. */
>>>> +#define VIRTIO_CONFIG_S_DRIVER        2
>>>> +/* Driver has used its parts of the config, and is happy */
>>>> +#define VIRTIO_CONFIG_S_DRIVER_OK    4
>>>> +/* We've given up on this device. */
>>>> +#define VIRTIO_CONFIG_S_FAILED        0x80
>>>> +
>>>> +/* from Linux's linux/virtio_ring.h */
>>>> +
>>>> +/* This marks a buffer as continuing via the next field. */
>>>> +#define VRING_DESC_F_NEXT    1
>>>> +/* This marks a buffer as write-only (otherwise read-only). */
>>>> +#define VRING_DESC_F_WRITE    2
>>>> +
>>>> +/* This means don't notify other side when buffer added. */
>>>> +#define VRING_USED_F_NO_NOTIFY    1
>>>> +/* This means don't interrupt guest when buffer consumed. */
>>>> +#define VRING_AVAIL_F_NO_INTERRUPT    1
>>>> +
>>>> +typedef struct VirtQueue VirtQueue;
>>>> +typedef struct VirtIODevice VirtIODevice;
>>>> +
>>>> +typedef struct VRingDesc
>>>> +{
>>>> +    uint64_t addr;
>>>> +    uint32_t len;
>>>> +    uint16_t flags;
>>>> +    uint16_t next;
>>>> +} VRingDesc;
>>>> +
>>>> +typedef struct VRingAvail
>>>> +{
>>>> +    uint16_t flags;
>>>> +    uint16_t idx;
>>>> +    uint16_t ring[0];
>>>> +} VRingAvail;
>>>> +
>>>> +typedef struct VRingUsedElem
>>>> +{
>>>> +    uint32_t id;
>>>> +    uint32_t len;
>>>> +} VRingUsedElem;
>>>> +
>>>> +typedef struct VRingUsed
>>>> +{
>>>> +    uint16_t flags;
>>>> +    uint16_t idx;
>>>> +    VRingUsedElem ring[0];
>>>> +} VRingUsed;
>>>> +
>>>> +typedef struct VRing
>>>> +{
>>>> +    unsigned int num;
>>>> +    VRingDesc *desc;
>>>> +    VRingAvail *avail;
>>>> +    VRingUsed *used;
>>>> +} VRing;
>>>> +
>>>> +struct VirtQueue
>>>> +{
>>>> +    VRing vring;
>>>> +    uint32_t pfn;
>>>> +    uint16_t last_avail_idx;
>>>> +    void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
>>>> +    int index;
>>>> +};
>>>> +
>>>> +#define VIRTQUEUE_MAX_SIZE 1024
>>>> +
>>>> +typedef struct VirtQueueElement
>>>> +{
>>>> +    unsigned int index;
>>>> +    unsigned int out_num;
>>>> +    unsigned int in_num;
>>>> +    struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
>>>> +    struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
>>>> +} VirtQueueElement;
>>>> +
>>>> +#define VIRTIO_PCI_QUEUE_MAX    16
>>>> +
>>>> +struct VirtIODevice
>>>> +{
>>>> +    PCIDevice pci_dev;
>>>> +    const char *name;
>>>> +    uint32_t addr;
>>>> +    uint16_t vendor;
>>>> +    uint16_t device;
>>>> +    uint8_t status;
>>>> +    uint8_t isr;
>>>> +    uint16_t queue_sel;
>>>> +    uint32_t features;
>>>> +    size_t config_len;
>>>> +    void *config;
>>>> +    uint32_t (*get_features)(VirtIODevice *vdev);
>>>> +    void (*set_features)(VirtIODevice *vdev, uint32_t val);
>>>> +    void (*update_config)(VirtIODevice *vdev, uint8_t *config);
>>>> +    VirtQueue vq[VIRTIO_PCI_QUEUE_MAX];
>>>> +};
>>>> +
>>>> +VirtIODevice *virtio_init_pci(PCIBus *bus, const char *name,
>>>> +                  uint16_t vendor, uint16_t device,
>>>> +                  uint16_t subvendor, uint16_t subdevice,
>>>> +                  uint8_t class_code, uint8_t subclass_code,
>>>> +                  uint8_t pif, size_t config_size,
>>>> +                  size_t struct_size);
>>>> +
>>>> +VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
>>>> +                void (*handle_output)(VirtIODevice *,
>>>> +                          VirtQueue *));
>>>> +
>>>> +void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
>>>> +            unsigned int len);
>>>> +
>>>> +int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem);
>>>> +
>>>> +void virtio_notify(VirtIODevice *vdev, VirtQueue *vq);
>>>> +
>>>> +#endif
>>>>         
>>>     
>>
>>
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>>
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>
>


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