diff options
Diffstat (limited to 'qemu/hw/virtio/dataplane/vring.c')
| -rw-r--r-- | qemu/hw/virtio/dataplane/vring.c | 453 |
1 files changed, 0 insertions, 453 deletions
diff --git a/qemu/hw/virtio/dataplane/vring.c b/qemu/hw/virtio/dataplane/vring.c deleted file mode 100644 index 07fd69c69..000000000 --- a/qemu/hw/virtio/dataplane/vring.c +++ /dev/null @@ -1,453 +0,0 @@ -/* 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/hw.h" -#include "exec/memory.h" -#include "exec/address-spaces.h" -#include "hw/virtio/virtio-access.h" -#include "hw/virtio/dataplane/vring.h" -#include "hw/virtio/dataplane/vring-accessors.h" -#include "qemu/error-report.h" - -/* vring_map can be coupled with vring_unmap or (if you still have the - * value returned in *mr) memory_region_unref. - */ -static void *vring_map(MemoryRegion **mr, hwaddr phys, hwaddr len, - bool is_write) -{ - MemoryRegionSection section = memory_region_find(get_system_memory(), phys, len); - - if (!section.mr || int128_get64(section.size) < len) { - goto out; - } - if (is_write && section.readonly) { - goto out; - } - if (!memory_region_is_ram(section.mr)) { - goto out; - } - - /* Ignore regions with dirty logging, we cannot mark them dirty */ - if (memory_region_get_dirty_log_mask(section.mr)) { - goto out; - } - - *mr = section.mr; - return memory_region_get_ram_ptr(section.mr) + section.offset_within_region; - -out: - memory_region_unref(section.mr); - *mr = NULL; - return NULL; -} - -static void vring_unmap(void *buffer, bool is_write) -{ - ram_addr_t addr; - MemoryRegion *mr; - - mr = qemu_ram_addr_from_host(buffer, &addr); - memory_region_unref(mr); -} - -/* 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; - - vring_ptr = vring_map(&vring->mr, 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 = virtio_queue_get_last_avail_idx(vdev, n); - vring->last_used_idx = vring_get_used_idx(vdev, vring); - 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, VirtIODevice *vdev, int n) -{ - virtio_queue_set_last_avail_idx(vdev, n, vring->last_avail_idx); - virtio_queue_invalidate_signalled_used(vdev, n); - - memory_region_unref(vring->mr); -} - -/* Disable guest->host notifies */ -void vring_disable_notification(VirtIODevice *vdev, Vring *vring) -{ - if (!virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { - vring_set_used_flags(vdev, vring, 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 (virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { - vring_avail_event(&vring->vr) = vring->vr.avail->idx; - } else { - vring_clear_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY); - } - smp_mb(); /* ensure update is seen before reading avail_idx */ - return !vring_more_avail(vdev, 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 (virtio_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) && - unlikely(!vring_more_avail(vdev, vring))) { - return true; - } - - if (!virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { - return !(vring_get_avail_flags(vdev, vring) & - 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(virtio_tswap16(vdev, vring_used_event(&vring->vr)), - new, old); -} - - -static int get_desc(Vring *vring, VirtQueueElement *elem, - struct vring_desc *desc) -{ - unsigned *num; - struct iovec *iov; - hwaddr *addr; - MemoryRegion *mr; - - if (desc->flags & VRING_DESC_F_WRITE) { - num = &elem->in_num; - iov = &elem->in_sg[*num]; - addr = &elem->in_addr[*num]; - } else { - num = &elem->out_num; - iov = &elem->out_sg[*num]; - addr = &elem->out_addr[*num]; - - /* If it's an output descriptor, they're all supposed - * to come before any input descriptors. */ - if (unlikely(elem->in_num)) { - error_report("Descriptor has out after in"); - return -EFAULT; - } - } - - /* Stop for now if there are not enough iovecs available. */ - if (*num >= VIRTQUEUE_MAX_SIZE) { - error_report("Invalid SG num: %u", *num); - return -EFAULT; - } - - /* TODO handle non-contiguous memory across region boundaries */ - iov->iov_base = vring_map(&mr, desc->addr, desc->len, - desc->flags & VRING_DESC_F_WRITE); - if (!iov->iov_base) { - error_report("Failed to map descriptor addr %#" PRIx64 " len %u", - (uint64_t)desc->addr, desc->len); - return -EFAULT; - } - - /* The MemoryRegion is looked up again and unref'ed later, leave the - * ref in place. */ - iov->iov_len = desc->len; - *addr = desc->addr; - *num += 1; - return 0; -} - -static void copy_in_vring_desc(VirtIODevice *vdev, - const struct vring_desc *guest, - struct vring_desc *host) -{ - host->addr = virtio_ldq_p(vdev, &guest->addr); - host->len = virtio_ldl_p(vdev, &guest->len); - host->flags = virtio_lduw_p(vdev, &guest->flags); - host->next = virtio_lduw_p(vdev, &guest->next); -} - -/* This is stolen from linux/drivers/vhost/vhost.c. */ -static int get_indirect(VirtIODevice *vdev, Vring *vring, - VirtQueueElement *elem, struct vring_desc *indirect) -{ - struct vring_desc desc; - unsigned int i = 0, count, found = 0; - int ret; - - /* 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; - MemoryRegion *mr; - - /* Translate indirect descriptor */ - desc_ptr = vring_map(&mr, - 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; - } - copy_in_vring_desc(vdev, desc_ptr, &desc); - memory_region_unref(mr); - - /* 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; - } - - ret = get_desc(vring, elem, &desc); - if (ret < 0) { - vring->broken |= (ret == -EFAULT); - return ret; - } - i = desc.next; - } while (desc.flags & VRING_DESC_F_NEXT); - return 0; -} - -static void vring_unmap_element(VirtQueueElement *elem) -{ - int i; - - /* This assumes that the iovecs, if changed, are never moved past - * the end of the valid area. This is true if iovec manipulations - * are done with iov_discard_front and iov_discard_back. - */ - for (i = 0; i < elem->out_num; i++) { - vring_unmap(elem->out_sg[i].iov_base, false); - } - - for (i = 0; i < elem->in_num; i++) { - vring_unmap(elem->in_sg[i].iov_base, true); - } -} - -/* 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, - VirtQueueElement *elem) -{ - struct vring_desc desc; - unsigned int i, head, found = 0, num = vring->vr.num; - uint16_t avail_idx, last_avail_idx; - int ret; - - /* Initialize elem so it can be safely unmapped */ - elem->in_num = elem->out_num = 0; - - /* If there was a fatal error then refuse operation */ - if (vring->broken) { - ret = -EFAULT; - goto out; - } - - /* Check it isn't doing very strange things with descriptor numbers. */ - last_avail_idx = vring->last_avail_idx; - avail_idx = vring_get_avail_idx(vdev, vring); - 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); - ret = -EFAULT; - goto out; - } - - /* If there's nothing new since last we looked. */ - if (avail_idx == last_avail_idx) { - ret = -EAGAIN; - goto out; - } - - /* 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_get_avail_ring(vdev, vring, last_avail_idx % num); - - elem->index = head; - - /* If their number is silly, that's an error. */ - if (unlikely(head >= num)) { - error_report("Guest says index %u > %u is available", head, num); - ret = -EFAULT; - goto out; - } - - i = head; - do { - if (unlikely(i >= num)) { - error_report("Desc index is %u > %u, head = %u", i, num, head); - ret = -EFAULT; - goto out; - } - if (unlikely(++found > num)) { - error_report("Loop detected: last one at %u vq size %u head %u", - i, num, head); - ret = -EFAULT; - goto out; - } - copy_in_vring_desc(vdev, &vring->vr.desc[i], &desc); - - /* Ensure descriptor is loaded before accessing fields */ - barrier(); - - if (desc.flags & VRING_DESC_F_INDIRECT) { - ret = get_indirect(vdev, vring, elem, &desc); - if (ret < 0) { - goto out; - } - continue; - } - - ret = get_desc(vring, elem, &desc); - if (ret < 0) { - goto out; - } - - i = desc.next; - } while (desc.flags & VRING_DESC_F_NEXT); - - /* On success, increment avail index. */ - vring->last_avail_idx++; - if (virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { - vring_avail_event(&vring->vr) = - virtio_tswap16(vdev, vring->last_avail_idx); - } - - return head; - -out: - assert(ret < 0); - if (ret == -EFAULT) { - vring->broken = true; - } - vring_unmap_element(elem); - return ret; -} - -/* After we've used one of their buffers, we tell them about it. - * - * Stolen from linux/drivers/vhost/vhost.c. - */ -void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem, - int len) -{ - unsigned int head = elem->index; - uint16_t new; - - vring_unmap_element(elem); - - /* 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. */ - vring_set_used_ring_id(vdev, vring, vring->last_used_idx % vring->vr.num, - head); - vring_set_used_ring_len(vdev, vring, vring->last_used_idx % vring->vr.num, - len); - - /* Make sure buffer is written before we update index. */ - smp_wmb(); - - new = ++vring->last_used_idx; - vring_set_used_idx(vdev, vring, new); - if (unlikely((int16_t)(new - vring->signalled_used) < (uint16_t)1)) { - vring->signalled_used_valid = false; - } -} |