hw: move virtio devices to hw/ subdirectories

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 363 insertions, 0 deletions

diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
new file mode 100644
index 0000000000..e0d6e83625
--- /dev/null
+++ b/hw/virtio/dataplane/vring.c
@@ -0,0 +1,363 @@
+/* Copyright 2012 Red Hat, Inc.
+ * Copyright IBM, Corp. 2012
+ *
+ * Based on Linux 2.6.39 vhost code:
+ * Copyright (C) 2009 Red Hat, Inc.
+ * Copyright (C) 2006 Rusty Russell IBM Corporation
+ *
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ *         Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * Inspiration, some code, and most witty comments come from
+ * Documentation/virtual/lguest/lguest.c, by Rusty Russell
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+
+#include "trace.h"
+#include "hw/virtio/dataplane/vring.h"
+#include "qemu/error-report.h"
+
+/* Map the guest's vring to host memory */
+bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
+{
+    hwaddr vring_addr = virtio_queue_get_ring_addr(vdev, n);
+    hwaddr vring_size = virtio_queue_get_ring_size(vdev, n);
+    void *vring_ptr;
+
+    vring->broken = false;
+
+    hostmem_init(&vring->hostmem);
+    vring_ptr = hostmem_lookup(&vring->hostmem, vring_addr, vring_size, true);
+    if (!vring_ptr) {
+        error_report("Failed to map vring "
+                     "addr %#" HWADDR_PRIx " size %" HWADDR_PRIu,
+                     vring_addr, vring_size);
+        vring->broken = true;
+        return false;
+    }
+
+    vring_init(&vring->vr, virtio_queue_get_num(vdev, n), vring_ptr, 4096);
+
+    vring->last_avail_idx = 0;
+    vring->last_used_idx = 0;
+    vring->signalled_used = 0;
+    vring->signalled_used_valid = false;
+
+    trace_vring_setup(virtio_queue_get_ring_addr(vdev, n),
+                      vring->vr.desc, vring->vr.avail, vring->vr.used);
+    return true;
+}
+
+void vring_teardown(Vring *vring)
+{
+    hostmem_finalize(&vring->hostmem);
+}
+
+/* Disable guest->host notifies */
+void vring_disable_notification(VirtIODevice *vdev, Vring *vring)
+{
+    if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
+        vring->vr.used->flags |= VRING_USED_F_NO_NOTIFY;
+    }
+}
+
+/* Enable guest->host notifies
+ *
+ * Return true if the vring is empty, false if there are more requests.
+ */
+bool vring_enable_notification(VirtIODevice *vdev, Vring *vring)
+{
+    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+        vring_avail_event(&vring->vr) = vring->vr.avail->idx;
+    } else {
+        vring->vr.used->flags &= ~VRING_USED_F_NO_NOTIFY;
+    }
+    smp_mb(); /* ensure update is seen before reading avail_idx */
+    return !vring_more_avail(vring);
+}
+
+/* This is stolen from linux/drivers/vhost/vhost.c:vhost_notify() */
+bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
+{
+    uint16_t old, new;
+    bool v;
+    /* Flush out used index updates. This is paired
+     * with the barrier that the Guest executes when enabling
+     * interrupts. */
+    smp_mb();
+
+    if ((vdev->guest_features & VIRTIO_F_NOTIFY_ON_EMPTY) &&
+        unlikely(vring->vr.avail->idx == vring->last_avail_idx)) {
+        return true;
+    }
+
+    if (!(vdev->guest_features & VIRTIO_RING_F_EVENT_IDX)) {
+        return !(vring->vr.avail->flags & VRING_AVAIL_F_NO_INTERRUPT);
+    }
+    old = vring->signalled_used;
+    v = vring->signalled_used_valid;
+    new = vring->signalled_used = vring->last_used_idx;
+    vring->signalled_used_valid = true;
+
+    if (unlikely(!v)) {
+        return true;
+    }
+
+    return vring_need_event(vring_used_event(&vring->vr), new, old);
+}
+
+/* This is stolen from linux/drivers/vhost/vhost.c. */
+static int get_indirect(Vring *vring,
+                        struct iovec iov[], struct iovec *iov_end,
+                        unsigned int *out_num, unsigned int *in_num,
+                        struct vring_desc *indirect)
+{
+    struct vring_desc desc;
+    unsigned int i = 0, count, found = 0;
+
+    /* Sanity check */
+    if (unlikely(indirect->len % sizeof(desc))) {
+        error_report("Invalid length in indirect descriptor: "
+                     "len %#x not multiple of %#zx",
+                     indirect->len, sizeof(desc));
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    count = indirect->len / sizeof(desc);
+    /* Buffers are chained via a 16 bit next field, so
+     * we can have at most 2^16 of these. */
+    if (unlikely(count > USHRT_MAX + 1)) {
+        error_report("Indirect buffer length too big: %d", indirect->len);
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    do {
+        struct vring_desc *desc_ptr;
+
+        /* Translate indirect descriptor */
+        desc_ptr = hostmem_lookup(&vring->hostmem,
+                                  indirect->addr + found * sizeof(desc),
+                                  sizeof(desc), false);
+        if (!desc_ptr) {
+            error_report("Failed to map indirect descriptor "
+                         "addr %#" PRIx64 " len %zu",
+                         (uint64_t)indirect->addr + found * sizeof(desc),
+                         sizeof(desc));
+            vring->broken = true;
+            return -EFAULT;
+        }
+        desc = *desc_ptr;
+
+        /* Ensure descriptor has been loaded before accessing fields */
+        barrier(); /* read_barrier_depends(); */
+
+        if (unlikely(++found > count)) {
+            error_report("Loop detected: last one at %u "
+                         "indirect size %u", i, count);
+            vring->broken = true;
+            return -EFAULT;
+        }
+
+        if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) {
+            error_report("Nested indirect descriptor");
+            vring->broken = true;
+            return -EFAULT;
+        }
+
+        /* Stop for now if there are not enough iovecs available. */
+        if (iov >= iov_end) {
+            return -ENOBUFS;
+        }
+
+        iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
+                                       desc.flags & VRING_DESC_F_WRITE);
+        if (!iov->iov_base) {
+            error_report("Failed to map indirect descriptor"
+                         "addr %#" PRIx64 " len %u",
+                         (uint64_t)desc.addr, desc.len);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        iov->iov_len = desc.len;
+        iov++;
+
+        /* If this is an input descriptor, increment that count. */
+        if (desc.flags & VRING_DESC_F_WRITE) {
+            *in_num += 1;
+        } else {
+            /* If it's an output descriptor, they're all supposed
+             * to come before any input descriptors. */
+            if (unlikely(*in_num)) {
+                error_report("Indirect descriptor "
+                             "has out after in: idx %u", i);
+                vring->broken = true;
+                return -EFAULT;
+            }
+            *out_num += 1;
+        }
+        i = desc.next;
+    } while (desc.flags & VRING_DESC_F_NEXT);
+    return 0;
+}
+
+/* This looks in the virtqueue and for the first available buffer, and converts
+ * it to an iovec for convenient access.  Since descriptors consist of some
+ * number of output then some number of input descriptors, it's actually two
+ * iovecs, but we pack them into one and note how many of each there were.
+ *
+ * This function returns the descriptor number found, or vq->num (which is
+ * never a valid descriptor number) if none was found.  A negative code is
+ * returned on error.
+ *
+ * Stolen from linux/drivers/vhost/vhost.c.
+ */
+int vring_pop(VirtIODevice *vdev, Vring *vring,
+              struct iovec iov[], struct iovec *iov_end,
+              unsigned int *out_num, unsigned int *in_num)
+{
+    struct vring_desc desc;
+    unsigned int i, head, found = 0, num = vring->vr.num;
+    uint16_t avail_idx, last_avail_idx;
+
+    /* If there was a fatal error then refuse operation */
+    if (vring->broken) {
+        return -EFAULT;
+    }
+
+    /* Check it isn't doing very strange things with descriptor numbers. */
+    last_avail_idx = vring->last_avail_idx;
+    avail_idx = vring->vr.avail->idx;
+    barrier(); /* load indices now and not again later */
+
+    if (unlikely((uint16_t)(avail_idx - last_avail_idx) > num)) {
+        error_report("Guest moved used index from %u to %u",
+                     last_avail_idx, avail_idx);
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    /* If there's nothing new since last we looked. */
+    if (avail_idx == last_avail_idx) {
+        return -EAGAIN;
+    }
+
+    /* Only get avail ring entries after they have been exposed by guest. */
+    smp_rmb();
+
+    /* Grab the next descriptor number they're advertising, and increment
+     * the index we've seen. */
+    head = vring->vr.avail->ring[last_avail_idx % num];
+
+    /* If their number is silly, that's an error. */
+    if (unlikely(head >= num)) {
+        error_report("Guest says index %u > %u is available", head, num);
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+        vring_avail_event(&vring->vr) = vring->vr.avail->idx;
+    }
+
+    /* When we start there are none of either input nor output. */
+    *out_num = *in_num = 0;
+
+    i = head;
+    do {
+        if (unlikely(i >= num)) {
+            error_report("Desc index is %u > %u, head = %u", i, num, head);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        if (unlikely(++found > num)) {
+            error_report("Loop detected: last one at %u vq size %u head %u",
+                         i, num, head);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        desc = vring->vr.desc[i];
+
+        /* Ensure descriptor is loaded before accessing fields */
+        barrier();
+
+        if (desc.flags & VRING_DESC_F_INDIRECT) {
+            int ret = get_indirect(vring, iov, iov_end, out_num, in_num, &desc);
+            if (ret < 0) {
+                return ret;
+            }
+            continue;
+        }
+
+        /* If there are not enough iovecs left, stop for now.  The caller
+         * should check if there are more descs available once they have dealt
+         * with the current set.
+         */
+        if (iov >= iov_end) {
+            return -ENOBUFS;
+        }
+
+        /* TODO handle non-contiguous memory across region boundaries */
+        iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
+                                       desc.flags & VRING_DESC_F_WRITE);
+        if (!iov->iov_base) {
+            error_report("Failed to map vring desc addr %#" PRIx64 " len %u",
+                         (uint64_t)desc.addr, desc.len);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        iov->iov_len  = desc.len;
+        iov++;
+
+        if (desc.flags & VRING_DESC_F_WRITE) {
+            /* If this is an input descriptor,
+             * increment that count. */
+            *in_num += 1;
+        } else {
+            /* If it's an output descriptor, they're all supposed
+             * to come before any input descriptors. */
+            if (unlikely(*in_num)) {
+                error_report("Descriptor has out after in: idx %d", i);
+                vring->broken = true;
+                return -EFAULT;
+            }
+            *out_num += 1;
+        }
+        i = desc.next;
+    } while (desc.flags & VRING_DESC_F_NEXT);
+
+    /* On success, increment avail index. */
+    vring->last_avail_idx++;
+    return head;
+}
+
+/* After we've used one of their buffers, we tell them about it.
+ *
+ * Stolen from linux/drivers/vhost/vhost.c.
+ */
+void vring_push(Vring *vring, unsigned int head, int len)
+{
+    struct vring_used_elem *used;
+    uint16_t new;
+
+    /* Don't touch vring if a fatal error occurred */
+    if (vring->broken) {
+        return;
+    }
+
+    /* The virtqueue contains a ring of used buffers.  Get a pointer to the
+     * next entry in that used ring. */
+    used = &vring->vr.used->ring[vring->last_used_idx % vring->vr.num];
+    used->id = head;
+    used->len = len;
+
+    /* Make sure buffer is written before we update index. */
+    smp_wmb();
+
+    new = vring->vr.used->idx = ++vring->last_used_idx;
+    if (unlikely((int16_t)(new - vring->signalled_used) < (uint16_t)1)) {
+        vring->signalled_used_valid = false;
+    }
+}