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-rw-r--r--pc-bios/s390-ccw/virtio.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
new file mode 100644
index 000000000..5d2c6e338
--- /dev/null
+++ b/pc-bios/s390-ccw/virtio.c
@@ -0,0 +1,323 @@
+/*
+ * 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 %%r2,%%r4,0x500"
+ : "=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;
+}