323 lines
8.6 KiB
C
323 lines
8.6 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 "libc.h"
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#include "s390-ccw.h"
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#include "cio.h"
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#include "virtio.h"
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#include "virtio-scsi.h"
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#include "bswap.h"
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#include "helper.h"
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#include "s390-time.h"
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#define VRING_WAIT_REPLY_TIMEOUT 30
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static VRing block[VIRTIO_MAX_VQS];
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static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
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__attribute__((__aligned__(PAGE_SIZE)));
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static VDev vdev = {
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.nr_vqs = 1,
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.vrings = block,
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.cmd_vr_idx = 0,
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.ring_area = ring_area,
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.wait_reply_timeout = VRING_WAIT_REPLY_TIMEOUT,
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.schid = { .one = 1 },
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.scsi_block_size = VIRTIO_SCSI_BLOCK_SIZE,
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.blk_factor = 1,
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};
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VDev *virtio_get_device(void)
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{
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return &vdev;
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}
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VirtioDevType virtio_get_device_type(void)
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{
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return vdev.senseid.cu_model;
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}
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/* virtio spec v1.0 para 4.3.3.2 */
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static long kvm_hypercall(unsigned long nr, unsigned long param1,
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unsigned long param2, unsigned long param3)
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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 ulong r_param3 asm("4") = param3;
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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), "d"(r_param3)
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: "memory", "cc");
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return retval;
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}
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static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
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{
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return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
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vq_idx, cookie);
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}
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/***********************************************
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* Virtio functions *
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***********************************************/
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int drain_irqs(SubChannelId schid)
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{
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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(VDev *vdev, int cmd, void *ptr, int len, bool sli)
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{
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Ccw1 ccw = {};
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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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if (sli) {
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ccw.flags |= CCW_FLAG_SLI;
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}
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return do_cio(vdev->schid, vdev->senseid.cu_type, ptr2u32(&ccw), CCW_FMT1);
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}
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static void vring_init(VRing *vr, VqInfo *info)
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{
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void *p = (void *) info->queue;
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debug_print_addr("init p", p);
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vr->id = info->index;
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vr->num = info->num;
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vr->desc = p;
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vr->avail = p + info->num * sizeof(VRingDesc);
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vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
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+ info->align - 1) & ~(info->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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vr->next_idx = 0;
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vr->cookie = 0;
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debug_print_addr("init vr", vr);
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}
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bool vring_notify(VRing *vr)
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{
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vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
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return vr->cookie >= 0;
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}
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void vring_send_buf(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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int vr_poll(VRing *vr)
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{
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if (vr->used->idx == vr->used_idx) {
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vring_notify(vr);
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yield();
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return 0;
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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 1; /* vr has been updated */
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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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int vring_wait_reply(void)
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{
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ulong target_second = get_time_seconds() + vdev.wait_reply_timeout;
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/* Wait for any queue to be updated by the host */
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do {
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int i, r = 0;
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for (i = 0; i < vdev.nr_vqs; i++) {
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r += vr_poll(&vdev.vrings[i]);
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}
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yield();
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if (r) {
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return 0;
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}
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} while (!vdev.wait_reply_timeout || (get_time_seconds() < target_second));
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return 1;
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}
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int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
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{
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VRing *vr = &vdev->vrings[vqid];
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int i = 0;
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do {
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vring_send_buf(vr, cmd[i].data, cmd[i].size,
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cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
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} while (cmd[i++].flags & VRING_DESC_F_NEXT);
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vring_wait_reply();
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if (drain_irqs(vr->schid)) {
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return -1;
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}
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return 0;
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}
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void virtio_setup_ccw(VDev *vdev)
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{
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int i, rc, cfg_size = 0;
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unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;
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struct VirtioFeatureDesc {
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uint32_t features;
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uint8_t index;
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} __attribute__((packed)) feats;
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IPL_assert(virtio_is_supported(vdev->schid), "PE");
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/* device ID has been established now */
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vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
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vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
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run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false);
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switch (vdev->senseid.cu_model) {
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case VIRTIO_ID_NET:
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vdev->nr_vqs = 2;
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vdev->cmd_vr_idx = 0;
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cfg_size = sizeof(vdev->config.net);
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break;
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case VIRTIO_ID_BLOCK:
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vdev->nr_vqs = 1;
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vdev->cmd_vr_idx = 0;
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cfg_size = sizeof(vdev->config.blk);
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break;
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case VIRTIO_ID_SCSI:
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vdev->nr_vqs = 3;
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vdev->cmd_vr_idx = VR_REQUEST;
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cfg_size = sizeof(vdev->config.scsi);
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break;
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default:
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panic("Unsupported virtio device\n");
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}
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IPL_assert(
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run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false) == 0,
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"Could not get block device configuration");
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/* Feature negotiation */
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for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) {
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feats.features = 0;
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feats.index = i;
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rc = run_ccw(vdev, CCW_CMD_READ_FEAT, &feats, sizeof(feats), false);
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IPL_assert(rc == 0, "Could not get features bits");
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vdev->guest_features[i] &= bswap32(feats.features);
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feats.features = bswap32(vdev->guest_features[i]);
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rc = run_ccw(vdev, CCW_CMD_WRITE_FEAT, &feats, sizeof(feats), false);
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IPL_assert(rc == 0, "Could not set features bits");
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}
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for (i = 0; i < vdev->nr_vqs; i++) {
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VqInfo info = {
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.queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
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.align = KVM_S390_VIRTIO_RING_ALIGN,
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.index = i,
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.num = 0,
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};
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VqConfig config = {
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.index = i,
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.num = 0,
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};
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IPL_assert(
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run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), false) == 0,
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"Could not get block device VQ configuration");
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info.num = config.num;
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vring_init(&vdev->vrings[i], &info);
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vdev->vrings[i].schid = vdev->schid;
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IPL_assert(
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run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info), false) == 0,
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"Cannot set VQ info");
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}
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IPL_assert(
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run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false) == 0,
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"Could not write status to host");
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}
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bool virtio_is_supported(SubChannelId schid)
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{
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vdev.schid = schid;
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memset(&vdev.senseid, 0, sizeof(vdev.senseid));
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/*
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* Run sense id command.
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* The size of the senseid data differs between devices (notably,
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* between virtio devices and dasds), so specify the largest possible
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* size and suppress the incorrect length indication for smaller sizes.
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*/
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if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid),
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true)) {
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return false;
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}
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if (vdev.senseid.cu_type == 0x3832) {
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switch (vdev.senseid.cu_model) {
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case VIRTIO_ID_BLOCK:
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case VIRTIO_ID_SCSI:
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case VIRTIO_ID_NET:
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return true;
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}
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}
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return false;
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}
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