/*
* 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 "s390-ccw.h"
#include "virtio.h"
struct vring block;
static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static long kvm_hypercall(unsigned long nr, unsigned long param1,
unsigned long param2)
{
register ulong r_nr asm("1") = nr;
register ulong r_param1 asm("2") = param1;
register ulong r_param2 asm("3") = param2;
register long retval asm("2");
asm volatile ("diag 2,4,0x500"
: "=d" (retval)
: "d" (r_nr), "0" (r_param1), "r"(r_param2)
: "memory", "cc");
return retval;
}
static void virtio_notify(struct subchannel_id schid)
{
kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32*)&schid, 0);
}
/***********************************************
* Virtio functions *
***********************************************/
static int drain_irqs(struct subchannel_id schid)
{
struct 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(struct subchannel_id schid, int cmd, void *ptr, int len)
{
struct ccw1 ccw = {};
struct cmd_orb orb = {};
struct schib schib;
int r;
/* start command processing */
stsch_err(schid, &schib);
schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
msch(schid, &schib);
/* start subchannel command */
orb.fmt = 1;
orb.cpa = (u32)(long)&ccw;
orb.lpm = 0x80;
ccw.cmd_code = cmd;
ccw.cda = (long)ptr;
ccw.count = len;
r = ssch(schid, &orb);
/*
* XXX Wait until device is done processing the CCW. For now we can
* assume that a simple tsch will have finished the CCW processing,
* but the architecture allows for asynchronous operation
*/
if (!r) {
r = drain_irqs(schid);
}
return r;
}
static void virtio_set_status(struct subchannel_id schid,
unsigned long dev_addr)
{
unsigned char status = dev_addr;
if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
virtio_panic("Could not write status to host!\n");
}
}
static void virtio_reset(struct subchannel_id schid)
{
run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
}
static void vring_init(struct vring *vr, unsigned int num, void *p,
unsigned long align)
{
debug_print_addr("init p", p);
vr->num = num;
vr->desc = p;
vr->avail = p + num*sizeof(struct vring_desc);
vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
& ~(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;
debug_print_addr("init vr", vr);
}
static void vring_notify(struct subchannel_id schid)
{
virtio_notify(schid);
}
static void vring_send_buf(struct 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++;
}
}
static u64 get_clock(void)
{
u64 r;
asm volatile("stck %0" : "=Q" (r) : : "cc");
return r;
}
static ulong get_second(void)
{
return (get_clock() >> 12) / 1000000;
}
/*
* Wait for the host to reply.
*
* timeout is in seconds if > 0.
*
* Returns 0 on success, 1 on timeout.
*/
static int vring_wait_reply(struct vring *vr, int timeout)
{
ulong target_second = get_second() + timeout;
struct subchannel_id schid = vr->schid;
int r = 0;
/* Wait until the used index has moved. */
while (vr->used->idx == vr->used_idx) {
vring_notify(schid);
if (timeout && (get_second() >= target_second)) {
r = 1;
break;
}
yield();
}
vr->used_idx = vr->used->idx;
vr->next_idx = 0;
vr->desc[0].len = 0;
vr->desc[0].flags = 0;
return r;
}
/***********************************************
* Virtio block *
***********************************************/
static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
{
struct virtio_blk_outhdr out_hdr;
u8 status;
int r;
/* Tell the host we want to read */
out_hdr.type = VIRTIO_BLK_T_IN;
out_hdr.ioprio = 99;
out_hdr.sector = sector;
vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
/* This is where we want to receive data */
vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
VRING_DESC_F_NEXT);
/* status field */
vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
VRING_HIDDEN_IS_CHAIN);
/* Now we can tell the host to read */
vring_wait_reply(&block, 0);
r = drain_irqs(block.schid);
if (r) {
/* Well, whatever status is supposed to contain... */
status = 1;
}
return status;
}
unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
ulong subchan_id, void *load_addr)
{
u8 status;
int sec = rec_list1;
int sec_num = (((rec_list2 >> 32)+ 1) & 0xffff);
int sec_len = rec_list2 >> 48;
ulong addr = (ulong)load_addr;
if (sec_len != SECTOR_SIZE) {
return -1;
}
sclp_print(".");
status = virtio_read_many(sec, (void*)addr, sec_num);
if (status) {
virtio_panic("I/O Error");
}
addr += sec_num * SECTOR_SIZE;
return addr;
}
int virtio_read(ulong sector, void *load_addr)
{
return virtio_read_many(sector, load_addr, 1);
}
void virtio_setup_block(struct subchannel_id schid)
{
struct vq_info_block info;
struct vq_config_block config = {};
virtio_reset(schid);
config.index = 0;
if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
virtio_panic("Could not get block device configuration\n");
}
vring_init(&block, config.num, (void*)(100 * 1024 * 1024),
KVM_S390_VIRTIO_RING_ALIGN);
info.queue = (100ULL * 1024ULL* 1024ULL);
info.align = KVM_S390_VIRTIO_RING_ALIGN;
info.index = 0;
info.num = config.num;
block.schid = schid;
if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
}
}
bool virtio_is_blk(struct subchannel_id schid)
{
int r;
struct senseid senseid = {};
/* run sense id command */
r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
if (r) {
return false;
}
if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
return false;
}
return true;
}
int enable_mss_facility(void)
{
int ret;
struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;
memset(sda_area, 0, PAGE_SIZE);
sda_area->request.length = 0x0400;
sda_area->request.code = 0x0031;
sda_area->operation_code = 0x2;
ret = chsc(sda_area);
if ((ret == 0) && (sda_area->response.code == 0x0001)) {
return 0;
}
return -EIO;
}
