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-rw-r--r--pc-bios/s390-ccw/virtio.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
new file mode 100644
index 0000000000..79e2941618
--- /dev/null
+++ b/pc-bios/s390-ccw/virtio.c
@@ -0,0 +1,274 @@
+/*
+ * 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 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 void drain_irqs(struct subchannel_id schid)
+{
+ struct irb irb = {};
+ while (1) {
+ if (tsch(schid, &irb)) {
+ return;
+ }
+ }
+}
+
+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
+ */
+ drain_irqs(schid);
+ return r;
+}
+
+static void virtio_set_status(struct subchannel_id schid,
+ unsigned long dev_addr)
+{
+ unsigned char status = dev_addr;
+ run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status));
+}
+
+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));
+
+ /* We're running with interrupts off anyways, so don't bother */
+ vr->used->flags = VRING_USED_F_NO_NOTIFY;
+
+ 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;
+
+ /* Chains only have a single ID */
+ if (!(flags & VRING_DESC_F_NEXT)) {
+ vr->avail->idx++;
+ }
+
+ vr->used->idx = vr->next_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;
+
+ while (vr->used->idx == vr->next_idx) {
+ vring_notify(schid);
+ if (timeout && (get_second() >= target_second)) {
+ r = 1;
+ break;
+ }
+ yield();
+ }
+
+ 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;
+
+ /* 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);
+
+ drain_irqs(block.schid);
+
+ 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;
+
+ virtio_reset(schid);
+
+ /* XXX need to fetch the 128 from host */
+ vring_init(&block, 128, (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 = 128;
+ block.schid = schid;
+
+ 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;
+}
+
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