The guest side must not manipulate the index for the used buffers. Instead, remember the state of the used buffer locally and wait until it has moved. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Acked-by: Alexander Graf <agraf@suse.de> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
323 lines
8 KiB
C
323 lines
8 KiB
C
/*
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* Virtio driver bits
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*
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* Copyright (c) 2013 Alexander Graf <agraf@suse.de>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or (at
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* your option) any later version. See the COPYING file in the top-level
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* directory.
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*/
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#include "s390-ccw.h"
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#include "virtio.h"
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struct vring block;
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static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
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static long kvm_hypercall(unsigned long nr, unsigned long param1,
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unsigned long param2)
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{
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register ulong r_nr asm("1") = nr;
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register ulong r_param1 asm("2") = param1;
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register ulong r_param2 asm("3") = param2;
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register long retval asm("2");
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asm volatile ("diag 2,4,0x500"
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: "=d" (retval)
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: "d" (r_nr), "0" (r_param1), "r"(r_param2)
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: "memory", "cc");
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return retval;
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}
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static void virtio_notify(struct subchannel_id schid)
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{
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kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32*)&schid, 0);
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}
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/***********************************************
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* Virtio functions *
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***********************************************/
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static int drain_irqs(struct subchannel_id schid)
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{
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struct irb irb = {};
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int r = 0;
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while (1) {
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/* FIXME: make use of TPI, for that enable subchannel and isc */
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if (tsch(schid, &irb)) {
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/* Might want to differentiate error codes later on. */
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if (irb.scsw.cstat) {
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r = -EIO;
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} else if (irb.scsw.dstat != 0xc) {
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r = -EIO;
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}
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return r;
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}
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}
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}
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static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
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{
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struct ccw1 ccw = {};
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struct cmd_orb orb = {};
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struct schib schib;
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int r;
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/* start command processing */
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stsch_err(schid, &schib);
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schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
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msch(schid, &schib);
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/* start subchannel command */
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orb.fmt = 1;
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orb.cpa = (u32)(long)&ccw;
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orb.lpm = 0x80;
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ccw.cmd_code = cmd;
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ccw.cda = (long)ptr;
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ccw.count = len;
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r = ssch(schid, &orb);
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/*
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* XXX Wait until device is done processing the CCW. For now we can
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* assume that a simple tsch will have finished the CCW processing,
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* but the architecture allows for asynchronous operation
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*/
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if (!r) {
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r = drain_irqs(schid);
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}
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return r;
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}
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static void virtio_set_status(struct subchannel_id schid,
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unsigned long dev_addr)
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{
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unsigned char status = dev_addr;
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if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
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virtio_panic("Could not write status to host!\n");
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}
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}
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static void virtio_reset(struct subchannel_id schid)
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{
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run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
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}
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static void vring_init(struct vring *vr, unsigned int num, void *p,
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unsigned long align)
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{
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debug_print_addr("init p", p);
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vr->num = num;
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vr->desc = p;
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vr->avail = p + num*sizeof(struct vring_desc);
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vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
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& ~(align - 1));
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/* Zero out all relevant field */
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vr->avail->flags = 0;
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vr->avail->idx = 0;
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/* We're running with interrupts off anyways, so don't bother */
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vr->used->flags = VRING_USED_F_NO_NOTIFY;
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vr->used->idx = 0;
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vr->used_idx = 0;
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debug_print_addr("init vr", vr);
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}
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static void vring_notify(struct subchannel_id schid)
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{
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virtio_notify(schid);
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}
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static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
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{
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/* For follow-up chains we need to keep the first entry point */
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if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
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vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
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}
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vr->desc[vr->next_idx].addr = (ulong)p;
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vr->desc[vr->next_idx].len = len;
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vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
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vr->desc[vr->next_idx].next = vr->next_idx;
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vr->desc[vr->next_idx].next++;
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vr->next_idx++;
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/* Chains only have a single ID */
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if (!(flags & VRING_DESC_F_NEXT)) {
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vr->avail->idx++;
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}
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}
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static u64 get_clock(void)
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{
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u64 r;
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asm volatile("stck %0" : "=Q" (r) : : "cc");
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return r;
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}
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static ulong get_second(void)
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{
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return (get_clock() >> 12) / 1000000;
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}
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/*
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* Wait for the host to reply.
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*
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* timeout is in seconds if > 0.
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*
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* Returns 0 on success, 1 on timeout.
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*/
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static int vring_wait_reply(struct vring *vr, int timeout)
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{
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ulong target_second = get_second() + timeout;
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struct subchannel_id schid = vr->schid;
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int r = 0;
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/* Wait until the used index has moved. */
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while (vr->used->idx == vr->used_idx) {
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vring_notify(schid);
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if (timeout && (get_second() >= target_second)) {
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r = 1;
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break;
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}
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yield();
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}
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vr->used_idx = vr->used->idx;
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vr->next_idx = 0;
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vr->desc[0].len = 0;
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vr->desc[0].flags = 0;
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return r;
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}
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/***********************************************
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* Virtio block *
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***********************************************/
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static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
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{
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struct virtio_blk_outhdr out_hdr;
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u8 status;
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int r;
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/* Tell the host we want to read */
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out_hdr.type = VIRTIO_BLK_T_IN;
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out_hdr.ioprio = 99;
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out_hdr.sector = sector;
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vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
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/* This is where we want to receive data */
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vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
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VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
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VRING_DESC_F_NEXT);
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/* status field */
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vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
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VRING_HIDDEN_IS_CHAIN);
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/* Now we can tell the host to read */
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vring_wait_reply(&block, 0);
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r = drain_irqs(block.schid);
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if (r) {
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/* Well, whatever status is supposed to contain... */
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status = 1;
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}
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return status;
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}
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unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
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ulong subchan_id, void *load_addr)
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{
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u8 status;
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int sec = rec_list1;
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int sec_num = (((rec_list2 >> 32)+ 1) & 0xffff);
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int sec_len = rec_list2 >> 48;
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ulong addr = (ulong)load_addr;
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if (sec_len != SECTOR_SIZE) {
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return -1;
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}
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sclp_print(".");
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status = virtio_read_many(sec, (void*)addr, sec_num);
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if (status) {
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virtio_panic("I/O Error");
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}
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addr += sec_num * SECTOR_SIZE;
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return addr;
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}
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int virtio_read(ulong sector, void *load_addr)
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{
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return virtio_read_many(sector, load_addr, 1);
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}
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void virtio_setup_block(struct subchannel_id schid)
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{
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struct vq_info_block info;
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struct vq_config_block config = {};
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virtio_reset(schid);
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config.index = 0;
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if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
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virtio_panic("Could not get block device configuration\n");
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}
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vring_init(&block, config.num, (void*)(100 * 1024 * 1024),
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KVM_S390_VIRTIO_RING_ALIGN);
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info.queue = (100ULL * 1024ULL* 1024ULL);
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info.align = KVM_S390_VIRTIO_RING_ALIGN;
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info.index = 0;
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info.num = config.num;
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block.schid = schid;
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if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
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virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
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}
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}
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bool virtio_is_blk(struct subchannel_id schid)
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{
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int r;
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struct senseid senseid = {};
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/* run sense id command */
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r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
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if (r) {
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return false;
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}
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if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
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return false;
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}
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return true;
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}
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int enable_mss_facility(void)
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{
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int ret;
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struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;
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memset(sda_area, 0, PAGE_SIZE);
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sda_area->request.length = 0x0400;
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sda_area->request.code = 0x0031;
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sda_area->operation_code = 0x2;
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ret = chsc(sda_area);
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if ((ret == 0) && (sda_area->response.code == 0x0001)) {
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return 0;
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}
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return -EIO;
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}
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