/* * Virtio driver bits * * Copyright (c) 2013 Alexander Graf * * 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 "virtio.h" #include "virtio-scsi.h" #include "bswap.h" #define VRING_WAIT_REPLY_TIMEOUT 3 static VRing block[VIRTIO_MAX_VQS]; static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS] __attribute__((__aligned__(PAGE_SIZE))); static char chsc_page[PAGE_SIZE] __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) { Ccw1 ccw = {}; CmdOrb orb = {}; Schib schib; int r; /* start command processing */ stsch_err(vdev->schid, &schib); /* enable the subchannel for IPL device */ schib.pmcw.ena = 1; msch(vdev->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(vdev->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(vdev->schid); } return r; } 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++; } } static u64 get_clock(void) { u64 r; asm volatile("stck %0" : "=Q" (r) : : "cc"); return r; } ulong get_second(void) { return (get_clock() >> 12) / 1000000; } 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_second() + 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_second() < 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); 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) == 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)); 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)); 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)) == 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)) == 0, "Cannot set VQ info"); } IPL_assert( run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status)) == 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 */ if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid))) { 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; } int enable_mss_facility(void) { int ret; ChscAreaSda *sda_area = (ChscAreaSda *) 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; }