@@ -14,7 +14,8 @@ OUT=out/
SRCBOTH=misc.c pmm.c stacks.c output.c util.c block.c floppy.c ata.c mouse.c \
kbd.c pci.c serial.c clock.c pic.c cdrom.c ps2port.c smp.c resume.c \
pnpbios.c pirtable.c vgahooks.c ramdisk.c pcibios.c blockcmd.c \
- usb.c usb-uhci.c usb-ohci.c usb-ehci.c usb-hid.c usb-msc.c
+ usb.c usb-uhci.c usb-ohci.c usb-ehci.c usb-hid.c usb-msc.c \
+ virtio-ring.c virtio-pci.c virtio-blk.c
SRC16=$(SRCBOTH) system.c disk.c apm.c font.c
SRC32FLAT=$(SRCBOTH) post.c shadow.c memmap.c coreboot.c boot.c \
acpi.c smm.c mptable.c smbios.c pciinit.c optionroms.c mtrr.c \
@@ -11,6 +11,7 @@
#include "util.h" // dprintf
#include "ata.h" // process_ata_op
#include "usb-msc.h" // process_usb_op
+#include "virtio-blk.h" // process_virtio_op
struct drives_s Drives VAR16VISIBLE;
@@ -289,6 +290,8 @@ process_op(struct disk_op_s *op)
return process_cdemu_op(op);
case DTYPE_USB:
return process_usb_op(op);
+ case DTYPE_VIRTIO:
+ return process_virtio_op(op);
default:
op->count = 0;
return DISK_RET_EPARAM;
@@ -136,6 +136,9 @@
#define CONFIG_SUBMODEL_ID 0x00
#define CONFIG_BIOS_REVISION 0x01
+// Support boot from virtio storage
+#define CONFIG_VIRTIO_BLK 1
+
// Various memory addresses used by the code.
#define BUILD_STACK_ADDR 0x7000
#define BUILD_S3RESUME_STACK_ADDR 0x1000
@@ -197,6 +197,7 @@ struct drive_s {
#define DTYPE_RAMDISK 0x04
#define DTYPE_CDEMU 0x05
#define DTYPE_USB 0x06
+#define DTYPE_VIRTIO 0x07
#define MAXDESCSIZE 80
@@ -2605,3 +2605,6 @@
#define PCI_DEVICE_ID_RME_DIGI32 0x9896
#define PCI_DEVICE_ID_RME_DIGI32_PRO 0x9897
#define PCI_DEVICE_ID_RME_DIGI32_8 0x9898
+
+#define PCI_VENDOR_ID_REDHAT_QUMRANET 0x1af4
+#define PCI_DEVICE_ID_VIRTIO_BLK 0x1001
@@ -23,6 +23,7 @@
#include "smbios.h" // smbios_init
#include "paravirt.h" // qemu_cfg_port_probe
#include "ps2port.h" // ps2port_setup
+#include "virtio-blk.h" // virtio_blk_setup
void
__set_irq(int vector, void *loc)
@@ -184,6 +185,7 @@ init_hw(void)
floppy_setup();
ata_setup();
ramdisk_setup();
+ virtio_blk_setup();
}
// Main setup code.
new file mode 100644
@@ -0,0 +1,158 @@
+// Virtio block boot support.
+//
+// Copyright (C) 2010 Red Hat Inc.
+//
+// Authors:
+// Gleb Natapov <gnatapov@redhat.com>
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+
+#include "util.h" // dprintf
+#include "pci.h" // foreachpci
+#include "config.h" // CONFIG_*
+#include "virtio-pci.h"
+#include "virtio-blk.h"
+#include "disk.h"
+
+struct virtiodrive_s {
+ struct drive_s drive;
+ struct vring_virtqueue *vq;
+ u16 ioaddr;
+};
+
+static int
+virtio_blk_read(struct disk_op_s *op)
+{
+ struct virtiodrive_s *vdrive_g =
+ container_of(op->drive_g, struct virtiodrive_s, drive);
+ struct vring_virtqueue *vq = GET_GLOBAL(vdrive_g->vq);
+ struct virtio_blk_outhdr hdr = {
+ .type = VIRTIO_BLK_T_IN,
+ .ioprio = 0,
+ .sector = op->lba,
+ };
+ u8 status = VIRTIO_BLK_S_UNSUPP;
+ struct vring_list sg[] = {
+ {
+ .addr = MAKE_FLATPTR(GET_SEG(SS), &hdr),
+ .length = sizeof(hdr),
+ },
+ {
+ .addr = op->buf_fl,
+ .length = GET_GLOBAL(vdrive_g->drive.blksize) * op->count,
+ },
+ {
+ .addr = MAKE_FLATPTR(GET_SEG(SS), &status),
+ .length = sizeof(status),
+ },
+ };
+
+ /* Add to virtqueue and kick host */
+ vring_add_buf(vq, sg, 1, 2, 0, 0);
+ vring_kick(GET_GLOBAL(vdrive_g->ioaddr), vq, 1);
+
+ /* Wait for reply */
+ while (!vring_more_used(vq))
+ udelay(5);
+
+ /* Reclaim virtqueue element */
+ vring_get_buf(vq, NULL);
+ return status == VIRTIO_BLK_S_OK ? DISK_RET_SUCCESS : DISK_RET_EBADTRACK;
+}
+
+int
+process_virtio_op(struct disk_op_s *op)
+{
+ switch (op->command) {
+ case CMD_READ:
+ return virtio_blk_read(op);
+ case CMD_FORMAT:
+ case CMD_WRITE:
+ return DISK_RET_EWRITEPROTECT;
+ case CMD_RESET:
+ case CMD_ISREADY:
+ case CMD_VERIFY:
+ case CMD_SEEK:
+ return DISK_RET_SUCCESS;
+ default:
+ op->count = 0;
+ return DISK_RET_EPARAM;
+ }
+}
+
+void
+virtio_blk_setup(void)
+{
+ ASSERT32FLAT();
+ if (! CONFIG_VIRTIO_BLK)
+ return;
+
+ dprintf(3, "init virtio-blk\n");
+
+ int bdf, max;
+ u32 id = PCI_VENDOR_ID_REDHAT_QUMRANET | (PCI_DEVICE_ID_VIRTIO_BLK << 16);
+ foreachpci(bdf, max) {
+ u32 v = pci_config_readl(bdf, PCI_VENDOR_ID);
+ if (v != id)
+ continue;
+ dprintf(3, "found virtio-blk at %x:%x\n", pci_bdf_to_bus(bdf),
+ pci_bdf_to_dev(bdf));
+ char *desc = malloc_tmphigh(MAXDESCSIZE);
+ struct virtiodrive_s *vdrive_g = malloc_fseg(sizeof(*vdrive_g));
+ struct vring_virtqueue *vq = malloc_low(sizeof(*vq));
+ if (!vdrive_g || !desc || !vq) {
+ free(vdrive_g);
+ free(desc);
+ free(vq);
+ warn_noalloc();
+ return;
+ }
+ memset(vdrive_g, 0, sizeof(*vdrive_g));
+ vdrive_g->drive.type = DTYPE_VIRTIO;
+ vdrive_g->drive.cntl_id = bdf;
+ vdrive_g->vq = vq;
+
+ u16 ioaddr = pci_config_readl(bdf, PCI_BASE_ADDRESS_0) &
+ PCI_BASE_ADDRESS_IO_MASK;
+
+ vdrive_g->ioaddr = ioaddr;
+
+ vp_reset(ioaddr);
+ vp_set_status(ioaddr, VIRTIO_CONFIG_S_ACKNOWLEDGE |
+ VIRTIO_CONFIG_S_DRIVER );
+
+ if (vp_find_vq(ioaddr, 0, vdrive_g->vq) < 0 ) {
+ free(vdrive_g);
+ free(desc);
+ free(vq);
+ dprintf(1, "fail to find vq for virtio-blk %x:%x\n",
+ pci_bdf_to_bus (bdf), pci_bdf_to_dev(bdf));
+ continue;
+ }
+
+ struct virtio_blk_config cfg;
+ vp_get(ioaddr, 0, &cfg, sizeof(cfg));
+
+ vdrive_g->drive.blksize = cfg.blk_size;
+ vdrive_g->drive.sectors = cfg.capacity;
+ dprintf(3, "virtio-blk %x:%x blksize=%d sectors=%u\n",
+ pci_bdf_to_bus (bdf), pci_bdf_to_dev(bdf),
+ vdrive_g->drive.blksize, (u32)vdrive_g->drive.sectors);
+
+ vdrive_g->drive.pchs.cylinders = cfg.cylinders;
+ vdrive_g->drive.pchs.heads = cfg.heads;
+ vdrive_g->drive.pchs.spt = cfg.sectors;
+
+ setup_translation(&vdrive_g->drive);
+ add_bcv_internal(&vdrive_g->drive);
+
+ snprintf(desc, MAXDESCSIZE, "Virtio disk PCI:%x:%x",
+ pci_bdf_to_bus(bdf), pci_bdf_to_dev(bdf));
+
+ vdrive_g->drive.desc = desc;
+
+ vp_set_status(ioaddr, VIRTIO_CONFIG_S_ACKNOWLEDGE |
+ VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK);
+ }
+}
+
new file mode 100644
@@ -0,0 +1,40 @@
+#ifndef _VIRTIO_BLK_H
+#define _VIRTIO_BLK_H
+
+struct virtio_blk_config
+{
+ u64 capacity;
+ u32 size_max;
+ u32 seg_max;
+ u16 cylinders;
+ u8 heads;
+ u8 sectors;
+ u32 blk_size;
+ u8 physical_block_exp;
+ u8 alignment_offset;
+ u16 min_io_size;
+ u32 opt_io_size;
+} __attribute__((packed));
+
+/* These two define direction. */
+#define VIRTIO_BLK_T_IN 0
+#define VIRTIO_BLK_T_OUT 1
+
+/* This is the first element of the read scatter-gather list. */
+struct virtio_blk_outhdr {
+ /* VIRTIO_BLK_T* */
+ u32 type;
+ /* io priority. */
+ u32 ioprio;
+ /* Sector (ie. 512 byte offset) */
+ u64 sector;
+};
+
+#define VIRTIO_BLK_S_OK 0
+#define VIRTIO_BLK_S_IOERR 1
+#define VIRTIO_BLK_S_UNSUPP 2
+
+int process_virtio_op(struct disk_op_s *op);
+void virtio_blk_setup(void);
+
+#endif /* _VIRTIO_BLK_H */
new file mode 100644
@@ -0,0 +1,67 @@
+/* virtio-pci.c - pci interface for virtio interface
+ *
+ * (c) Copyright 2008 Bull S.A.S.
+ *
+ * Author: Laurent Vivier <Laurent.Vivier@bull.net>
+ *
+ * some parts from Linux Virtio PCI driver
+ *
+ * Copyright IBM Corp. 2007
+ * Authors: Anthony Liguori <aliguori@us.ibm.com>
+ *
+ * Adopted for Seabios: Gleb Natapov <gleb@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPLv3
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "virtio-ring.h"
+#include "virtio-pci.h"
+
+int vp_find_vq(unsigned int ioaddr, int queue_index,
+ struct vring_virtqueue *vq)
+{
+ struct vring * vr = &vq->vring;
+ u16 num;
+
+ ASSERT32FLAT();
+ /* 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) {
+ dprintf(1, "ERROR: queue size is 0\n");
+ return -1;
+ }
+
+ if (num > MAX_QUEUE_NUM) {
+ dprintf(1, "ERROR: queue size %d > %d\n", num, MAX_QUEUE_NUM);
+ return -1;
+ }
+
+ /* check if the queue is already active */
+
+ if (inl(ioaddr + VIRTIO_PCI_QUEUE_PFN)) {
+ dprintf(1, "ERROR: queue already active\n");
+ return -1;
+ }
+
+ vq->queue_index = queue_index;
+
+ /* initialize the queue */
+
+ vring_init(vr, num, (unsigned char*)&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;
+}
new file mode 100644
@@ -0,0 +1,97 @@
+#ifndef _VIRTIO_PCI_H
+#define _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
+
+/* The bit of the ISR which indicates a device configuration change. */
+#define VIRTIO_PCI_ISR_CONFIG 0x2
+
+/* The remaining space is defined by each driver as the per-driver
+ * configuration space */
+#define VIRTIO_PCI_CONFIG 20
+
+/* Virtio ABI version, this must match exactly */
+#define VIRTIO_PCI_ABI_VERSION 0
+
+static inline u32 vp_get_features(unsigned int ioaddr)
+{
+ return inl(ioaddr + VIRTIO_PCI_HOST_FEATURES);
+}
+
+static inline void vp_set_features(unsigned int ioaddr, u32 features)
+{
+ outl(features, ioaddr + VIRTIO_PCI_GUEST_FEATURES);
+}
+
+static inline void vp_get(unsigned int ioaddr, unsigned offset,
+ void *buf, unsigned len)
+{
+ u8 *ptr = buf;
+ unsigned i;
+
+ for (i = 0; i < len; i++)
+ ptr[i] = inb(ioaddr + VIRTIO_PCI_CONFIG + offset + i);
+}
+
+static inline u8 vp_get_status(unsigned int ioaddr)
+{
+ return inb(ioaddr + VIRTIO_PCI_STATUS);
+}
+
+static inline void vp_set_status(unsigned int ioaddr, u8 status)
+{
+ if (status == 0) /* reset */
+ return;
+ outb(status, ioaddr + VIRTIO_PCI_STATUS);
+}
+
+
+static inline void vp_reset(unsigned int ioaddr)
+{
+ outb(0, ioaddr + VIRTIO_PCI_STATUS);
+ (void)inb(ioaddr + VIRTIO_PCI_ISR);
+}
+
+static inline void vp_notify(unsigned int ioaddr, int queue_index)
+{
+ outw(queue_index, ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
+}
+
+static inline void vp_del_vq(unsigned int ioaddr, int queue_index)
+{
+ /* select the queue */
+
+ outw(queue_index, ioaddr + VIRTIO_PCI_QUEUE_SEL);
+
+ /* deactivate the queue */
+
+ outl(0, ioaddr + VIRTIO_PCI_QUEUE_PFN);
+}
+
+int vp_find_vq(unsigned int ioaddr, int queue_index,
+ struct vring_virtqueue *vq);
+#endif /* _VIRTIO_PCI_H_ */
new file mode 100644
@@ -0,0 +1,152 @@
+/* virtio-pci.c - virtio ring management
+ *
+ * (c) Copyright 2008 Bull S.A.S.
+ *
+ * Author: Laurent Vivier <Laurent.Vivier@bull.net>
+ *
+ * some parts from Linux Virtio Ring
+ *
+ * Copyright Rusty Russell IBM Corporation 2007
+ *
+ * Adopted for Seabios: Gleb Natapov <gleb@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPLv3
+ * See the COPYING file in the top-level directory.
+ *
+ *
+ */
+
+#include "virtio-ring.h"
+#include "virtio-pci.h"
+
+#define BUG() do { \
+ dprintf(1, "BUG: failure at %s:%d/%s()!\n", \
+ __FILE__, __LINE__, __FUNCTION__); \
+ while(1); \
+ } while (0)
+#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
+
+/*
+ * vring_more_used
+ *
+ * is there some used buffers ?
+ *
+ */
+
+int vring_more_used(struct vring_virtqueue *vq)
+{
+ struct vring_used *used = GET_FLATPTR(vq->vring.used);
+ wmb();
+ return GET_FLATPTR(vq->last_used_idx) != GET_FLATPTR(used->idx);
+}
+
+/*
+ * vring_free
+ *
+ * put at the begin of the free list the current desc[head]
+ */
+
+void vring_detach(struct vring_virtqueue *vq, unsigned int head)
+{
+ struct vring *vr = &vq->vring;
+ struct vring_desc *desc = GET_FLATPTR(vr->desc);
+ unsigned int i;
+
+ /* find end of given descriptor */
+
+ i = head;
+ while (GET_FLATPTR(desc[i].flags) & VRING_DESC_F_NEXT)
+ i = GET_FLATPTR(desc[i].next);
+
+ /* link it with free list and point to it */
+
+ SET_FLATPTR(desc[i].next, GET_FLATPTR(vq->free_head));
+ wmb();
+ SET_FLATPTR(vq->free_head, head);
+}
+
+/*
+ * vring_get_buf
+ *
+ * get a buffer from the used list
+ *
+ */
+
+int vring_get_buf(struct vring_virtqueue *vq, unsigned int *len)
+{
+ struct vring *vr = &vq->vring;
+ struct vring_used_elem *elem;
+ struct vring_used *used = GET_FLATPTR(vq->vring.used);
+ u32 id;
+ int ret;
+
+// BUG_ON(!vring_more_used(vq));
+
+ elem = &used->ring[GET_FLATPTR(vq->last_used_idx) % GET_FLATPTR(vr->num)];
+ wmb();
+ id = GET_FLATPTR(elem->id);
+ if (len != NULL)
+ *len = GET_FLATPTR(elem->len);
+
+ ret = GET_FLATPTR(vq->vdata[id]);
+
+ vring_detach(vq, id);
+
+ SET_FLATPTR(vq->last_used_idx, GET_FLATPTR(vq->last_used_idx) + 1);
+
+ return ret;
+}
+
+void vring_add_buf(struct vring_virtqueue *vq,
+ struct vring_list list[],
+ unsigned int out, unsigned int in,
+ int index, int num_added)
+{
+ struct vring *vr = &vq->vring;
+ int i, av, head, prev;
+ struct vring_desc *desc = GET_FLATPTR(vr->desc);
+ struct vring_avail *avail = GET_FLATPTR(vr->avail);
+
+ BUG_ON(out + in == 0);
+
+ prev = 0;
+ head = GET_FLATPTR(vq->free_head);
+ for (i = head; out; i = GET_FLATPTR(desc[i].next), out--) {
+ SET_FLATPTR(desc[i].flags, VRING_DESC_F_NEXT);
+ SET_FLATPTR(desc[i].addr, (u64)virt_to_phys(list->addr));
+ SET_FLATPTR(desc[i].len, list->length);
+ prev = i;
+ list++;
+ }
+ for ( ; in; i = GET_FLATPTR(desc[i].next), in--) {
+ SET_FLATPTR(desc[i].flags, VRING_DESC_F_NEXT|VRING_DESC_F_WRITE);
+ SET_FLATPTR(desc[i].addr, (u64)virt_to_phys(list->addr));
+ SET_FLATPTR(desc[i].len, list->length);
+ prev = i;
+ list++;
+ }
+ SET_FLATPTR(desc[prev].flags,
+ GET_FLATPTR(desc[prev].flags) & ~VRING_DESC_F_NEXT);
+
+ SET_FLATPTR(vq->free_head, i);
+
+ SET_FLATPTR(vq->vdata[head], index);
+
+ av = (GET_FLATPTR(avail->idx) + num_added) % GET_FLATPTR(vr->num);
+ SET_FLATPTR(avail->ring[av], head);
+ wmb();
+}
+
+void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added)
+{
+ struct vring *vr = &vq->vring;
+ struct vring_avail *avail = GET_FLATPTR(vr->avail);
+ struct vring_used *used = GET_FLATPTR(vq->vring.used);
+
+ wmb();
+ SET_FLATPTR(avail->idx, GET_FLATPTR(avail->idx) + num_added);
+
+ mb();
+ if (!(GET_FLATPTR(used->flags) & VRING_USED_F_NO_NOTIFY))
+ vp_notify(ioaddr, GET_FLATPTR(vq->queue_index));
+}
new file mode 100644
@@ -0,0 +1,125 @@
+#ifndef _VIRTIO_RING_H
+#define _VIRTIO_RING_H
+
+#define PAGE_SHIFT 12
+#define PAGE_MASK (PAGE_SIZE-1)
+
+#define virt_to_phys(v) (unsigned long)(v)
+#define phys_to_virt(p) (void*)(p)
+#define wmb() barrier()
+#define mb() barrier()
+
+/* 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
+
+#define MAX_QUEUE_NUM (128)
+
+#define VRING_DESC_F_NEXT 1
+#define VRING_DESC_F_WRITE 2
+
+#define VRING_AVAIL_F_NO_INTERRUPT 1
+
+#define VRING_USED_F_NO_NOTIFY 1
+
+struct vring_desc
+{
+ u64 addr;
+ u32 len;
+ u16 flags;
+ u16 next;
+};
+
+struct vring_avail
+{
+ u16 flags;
+ u16 idx;
+ u16 ring[0];
+};
+
+struct vring_used_elem
+{
+ u32 id;
+ u32 len;
+};
+
+struct vring_used
+{
+ u16 flags;
+ u16 idx;
+ struct vring_used_elem ring[];
+};
+
+struct vring {
+ unsigned int num;
+ struct vring_desc *desc;
+ struct vring_avail *avail;
+ struct vring_used *used;
+};
+
+#define vring_size(num) \
+ (((((sizeof(struct vring_desc) * num) + \
+ (sizeof(struct vring_avail) + sizeof(u16) * num)) \
+ + PAGE_MASK) & ~PAGE_MASK) + \
+ (sizeof(struct vring_used) + sizeof(struct vring_used_elem) * num))
+
+typedef unsigned char virtio_queue_t[PAGE_MASK + vring_size(MAX_QUEUE_NUM)];
+
+struct vring_virtqueue {
+ virtio_queue_t queue;
+ struct vring vring;
+ u16 free_head;
+ u16 last_used_idx;
+ u16 vdata[MAX_QUEUE_NUM];
+ /* PCI */
+ int queue_index;
+};
+
+struct vring_list {
+ char *addr;
+ unsigned int length;
+};
+
+static inline void vring_init(struct vring *vr,
+ unsigned int num, unsigned char *queue)
+{
+ unsigned int i;
+ unsigned long pa;
+
+ ASSERT32FLAT();
+ vr->num = num;
+
+ /* physical address of desc must be page aligned */
+
+ pa = virt_to_phys(queue);
+ pa = (pa + PAGE_MASK) & ~PAGE_MASK;
+ vr->desc = phys_to_virt(pa);
+
+ vr->avail = (struct vring_avail *)&vr->desc[num];
+
+ /* physical address of used must be page aligned */
+
+ pa = virt_to_phys(&vr->avail->ring[num]);
+ pa = (pa + PAGE_MASK) & ~PAGE_MASK;
+ vr->used = phys_to_virt(pa);
+
+ for (i = 0; i < num - 1; i++)
+ vr->desc[i].next = i + 1;
+ vr->desc[i].next = 0;
+}
+
+int vring_more_used(struct vring_virtqueue *vq);
+void vring_detach(struct vring_virtqueue *vq, unsigned int head);
+int vring_get_buf(struct vring_virtqueue *vq, unsigned int *len);
+void vring_add_buf(struct vring_virtqueue *vq, struct vring_list list[],
+ unsigned int out, unsigned int in,
+ int index, int num_added);
+void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added);
+
+#endif /* _VIRTIO_RING_H_ */