/*
* Virtio driver bits
*
* Copyright (c) 2013 Alexander Graf <agraf@suse.de>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include "libc.h"
#include "s390-ccw.h"
#include "cio.h"
#include "virtio.h"
#include "virtio-scsi.h"
#include "bswap.h"
#include "helper.h"
#include "s390-time.h"
#define VRING_WAIT_REPLY_TIMEOUT 30
static VRing block[VIRTIO_MAX_VQS];
static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
__attribute__((__aligned__(PAGE_SIZE)));
static VDev vdev = {
.nr_vqs = 1,
.vrings = block,
.cmd_vr_idx = 0,
.ring_area = ring_area,
.wait_reply_timeout = VRING_WAIT_REPLY_TIMEOUT,
.schid = { .one = 1 },
.scsi_block_size = VIRTIO_SCSI_BLOCK_SIZE,
.blk_factor = 1,
};
VDev *virtio_get_device(void)
{
return &vdev;
}
VirtioDevType virtio_get_device_type(void)
{
return vdev.senseid.cu_model;
}
/* virtio spec v1.0 para 4.3.3.2 */
static long kvm_hypercall(unsigned long nr, unsigned long param1,
unsigned long param2, unsigned long param3)
{
register ulong r_nr asm("1") = nr;
register ulong r_param1 asm("2") = param1;
register ulong r_param2 asm("3") = param2;
register ulong r_param3 asm("4") = param3;
register long retval asm("2");
asm volatile ("diag 2,4,0x500"
: "=d" (retval)
: "d" (r_nr), "0" (r_param1), "r"(r_param2), "d"(r_param3)
: "memory", "cc");
return retval;
}
static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
{
return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
vq_idx, cookie);
}
/***********************************************
* Virtio functions *
***********************************************/
int drain_irqs(SubChannelId schid)
{
Irb irb = {};
int r = 0;
while (1) {
/* FIXME: make use of TPI, for that enable subchannel and isc */
if (tsch(schid, &irb)) {
/* Might want to differentiate error codes later on. */
if (irb.scsw.cstat) {
r = -EIO;
} else if (irb.scsw.dstat != 0xc) {
r = -EIO;
}
return r;
}
}
}
static int run_ccw(VDev *vdev, int cmd, void *ptr, int len, bool sli)
{
Ccw1 ccw = {};
ccw.cmd_code = cmd;
ccw.cda = (long)ptr;
ccw.count = len;
if (sli) {
ccw.flags |= CCW_FLAG_SLI;
}
return do_cio(vdev->schid, vdev->senseid.cu_type, ptr2u32(&ccw), CCW_FMT1);
}
static void vring_init(VRing *vr, VqInfo *info)
{
void *p = (void *) info->queue;
debug_print_addr("init p", p);
vr->id = info->index;
vr->num = info->num;
vr->desc = p;
vr->avail = p + info->num * sizeof(VRingDesc);
vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
+ info->align - 1) & ~(info->align - 1));
/* Zero out all relevant field */
vr->avail->flags = 0;
vr->avail->idx = 0;
/* We're running with interrupts off anyways, so don't bother */
vr->used->flags = VRING_USED_F_NO_NOTIFY;
vr->used->idx = 0;
vr->used_idx = 0;
vr->next_idx = 0;
vr->cookie = 0;
debug_print_addr("init vr", vr);
}
bool vring_notify(VRing *vr)
{
vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
return vr->cookie >= 0;
}
void vring_send_buf(VRing *vr, void *p, int len, int flags)
{
/* For follow-up chains we need to keep the first entry point */
if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
}
vr->desc[vr->next_idx].addr = (ulong)p;
vr->desc[vr->next_idx].len = len;
vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
vr->desc[vr->next_idx].next = vr->next_idx;
vr->desc[vr->next_idx].next++;
vr->next_idx++;
/* Chains only have a single ID */
if (!(flags & VRING_DESC_F_NEXT)) {
vr->avail->idx++;
}
}
int vr_poll(VRing *vr)
{
if (vr->used->idx == vr->used_idx) {
vring_notify(vr);
yield();
return 0;
}
vr->used_idx = vr->used->idx;
vr->next_idx = 0;
vr->desc[0].len = 0;
vr->desc[0].flags = 0;
return 1; /* vr has been updated */
}
/*
* Wait for the host to reply.
*
* timeout is in seconds if > 0.
*
* Returns 0 on success, 1 on timeout.
*/
int vring_wait_reply(void)
{
ulong target_second = get_time_seconds() + vdev.wait_reply_timeout;
/* Wait for any queue to be updated by the host */
do {
int i, r = 0;
for (i = 0; i < vdev.nr_vqs; i++) {
r += vr_poll(&vdev.vrings[i]);
}
yield();
if (r) {
return 0;
}
} while (!vdev.wait_reply_timeout || (get_time_seconds() < target_second));
return 1;
}
int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
{
VRing *vr = &vdev->vrings[vqid];
int i = 0;
do {
vring_send_buf(vr, cmd[i].data, cmd[i].size,
cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
} while (cmd[i++].flags & VRING_DESC_F_NEXT);
vring_wait_reply();
if (drain_irqs(vr->schid)) {
return -1;
}
return 0;
}
void virtio_setup_ccw(VDev *vdev)
{
int i, rc, cfg_size = 0;
unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;
struct VirtioFeatureDesc {
uint32_t features;
uint8_t index;
} __attribute__((packed)) feats;
IPL_assert(virtio_is_supported(vdev->schid), "PE");
/* device ID has been established now */
vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false);
switch (vdev->senseid.cu_model) {
case VIRTIO_ID_NET:
vdev->nr_vqs = 2;
vdev->cmd_vr_idx = 0;
cfg_size = sizeof(vdev->config.net);
break;
case VIRTIO_ID_BLOCK:
vdev->nr_vqs = 1;
vdev->cmd_vr_idx = 0;
cfg_size = sizeof(vdev->config.blk);
break;
case VIRTIO_ID_SCSI:
vdev->nr_vqs = 3;
vdev->cmd_vr_idx = VR_REQUEST;
cfg_size = sizeof(vdev->config.scsi);
break;
default:
panic("Unsupported virtio device\n");
}
IPL_assert(
run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false) == 0,
"Could not get block device configuration");
/* Feature negotiation */
for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) {
feats.features = 0;
feats.index = i;
rc = run_ccw(vdev, CCW_CMD_READ_FEAT, &feats, sizeof(feats), false);
IPL_assert(rc == 0, "Could not get features bits");
vdev->guest_features[i] &= bswap32(feats.features);
feats.features = bswap32(vdev->guest_features[i]);
rc = run_ccw(vdev, CCW_CMD_WRITE_FEAT, &feats, sizeof(feats), false);
IPL_assert(rc == 0, "Could not set features bits");
}
for (i = 0; i < vdev->nr_vqs; i++) {
VqInfo info = {
.queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
.align = KVM_S390_VIRTIO_RING_ALIGN,
.index = i,
.num = 0,
};
VqConfig config = {
.index = i,
.num = 0,
};
IPL_assert(
run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), false) == 0,
"Could not get block device VQ configuration");
info.num = config.num;
vring_init(&vdev->vrings[i], &info);
vdev->vrings[i].schid = vdev->schid;
IPL_assert(
run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info), false) == 0,
"Cannot set VQ info");
}
IPL_assert(
run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false) == 0,
"Could not write status to host");
}
bool virtio_is_supported(SubChannelId schid)
{
vdev.schid = schid;
memset(&vdev.senseid, 0, sizeof(vdev.senseid));
/*
* Run sense id command.
* The size of the senseid data differs between devices (notably,
* between virtio devices and dasds), so specify the largest possible
* size and suppress the incorrect length indication for smaller sizes.
*/
if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid),
true)) {
return false;
}
if (vdev.senseid.cu_type == 0x3832) {
switch (vdev.senseid.cu_model) {
case VIRTIO_ID_BLOCK:
case VIRTIO_ID_SCSI:
case VIRTIO_ID_NET:
return true;
}
}
return false;
}
