This patch adds native support for booting from virtio disks to Seabios.
Signed-off-by: Gleb Natapov gleb@redhat.com ---
Changelog: v1->v2: - free memory in case of vq initialization error. - change license of virtio ring/pci to LGPLv3 with permission of Laurent Vivier (aka the author). v2->v3: - free memory in case one of allocations failed
diff --git a/Makefile b/Makefile index 327a1bf..d0b8881 100644 --- a/Makefile +++ b/Makefile @@ -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 \ diff --git a/src/block.c b/src/block.c index ddf441f..b6b1902 100644 --- a/src/block.c +++ b/src/block.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; diff --git a/src/config.h b/src/config.h index b101174..ad569c6 100644 --- a/src/config.h +++ b/src/config.h @@ -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 diff --git a/src/disk.h b/src/disk.h index 0cd1b74..9e5b083 100644 --- a/src/disk.h +++ b/src/disk.h @@ -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
diff --git a/src/pci_ids.h b/src/pci_ids.h index 1800f1d..e1cded2 100644 --- a/src/pci_ids.h +++ b/src/pci_ids.h @@ -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 diff --git a/src/post.c b/src/post.c index 638b0f7..25535e2 100644 --- a/src/post.c +++ b/src/post.c @@ -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. diff --git a/src/virtio-blk.c b/src/virtio-blk.c new file mode 100644 index 0000000..f106bdf --- /dev/null +++ b/src/virtio-blk.c @@ -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); + } +} + diff --git a/src/virtio-blk.h b/src/virtio-blk.h new file mode 100644 index 0000000..3369ea4 --- /dev/null +++ b/src/virtio-blk.h @@ -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 */ diff --git a/src/virtio-pci.c b/src/virtio-pci.c new file mode 100644 index 0000000..e171ea3 --- /dev/null +++ b/src/virtio-pci.c @@ -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; +} diff --git a/src/virtio-pci.h b/src/virtio-pci.h new file mode 100644 index 0000000..6932036 --- /dev/null +++ b/src/virtio-pci.h @@ -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_ */ diff --git a/src/virtio-ring.c b/src/virtio-ring.c new file mode 100644 index 0000000..f4a2efe --- /dev/null +++ b/src/virtio-ring.c @@ -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)); +} diff --git a/src/virtio-ring.h b/src/virtio-ring.h new file mode 100644 index 0000000..b97d572 --- /dev/null +++ b/src/virtio-ring.h @@ -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_ */ -- Gleb.