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@@ -1,549 +0,0 @@
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-/* Copyright 2012 Red Hat, Inc.
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- * Copyright IBM, Corp. 2012
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- *
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- * Based on Linux 2.6.39 vhost code:
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- * Copyright (C) 2009 Red Hat, Inc.
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- * Copyright (C) 2006 Rusty Russell IBM Corporation
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- *
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- * Author: Michael S. Tsirkin <mst@redhat.com>
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- * Stefan Hajnoczi <stefanha@redhat.com>
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- *
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- * Inspiration, some code, and most witty comments come from
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- * Documentation/virtual/lguest/lguest.c, by Rusty Russell
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- *
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- * This work is licensed under the terms of the GNU GPL, version 2.
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- */
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-
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-#include "qemu/osdep.h"
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-#include "trace.h"
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-#include "hw/hw.h"
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-#include "exec/memory.h"
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-#include "exec/address-spaces.h"
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-#include "hw/virtio/virtio-access.h"
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-#include "hw/virtio/dataplane/vring.h"
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-#include "hw/virtio/dataplane/vring-accessors.h"
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-#include "qemu/error-report.h"
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-
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-/* vring_map can be coupled with vring_unmap or (if you still have the
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- * value returned in *mr) memory_region_unref.
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- * Returns NULL on failure.
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- * Callers that can handle a partial mapping must supply mapped_len pointer to
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- * get the actual length mapped.
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- * Passing mapped_len == NULL requires either a full mapping or a failure.
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- */
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-static void *vring_map(MemoryRegion **mr, hwaddr phys,
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- hwaddr len, hwaddr *mapped_len,
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- bool is_write)
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-{
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- MemoryRegionSection section = memory_region_find(get_system_memory(), phys, len);
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- uint64_t size;
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-
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- if (!section.mr) {
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- goto out;
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- }
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-
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- size = int128_get64(section.size);
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- assert(size);
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-
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- /* Passing mapped_len == NULL requires either a full mapping or a failure. */
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- if (!mapped_len && size < len) {
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- goto out;
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- }
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-
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- if (is_write && section.readonly) {
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- goto out;
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- }
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- if (!memory_region_is_ram(section.mr)) {
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- goto out;
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- }
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-
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- /* Ignore regions with dirty logging, we cannot mark them dirty */
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- if (memory_region_get_dirty_log_mask(section.mr)) {
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- goto out;
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- }
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-
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- if (mapped_len) {
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- *mapped_len = MIN(size, len);
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- }
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-
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- *mr = section.mr;
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- return memory_region_get_ram_ptr(section.mr) + section.offset_within_region;
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-
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-out:
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- memory_region_unref(section.mr);
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- *mr = NULL;
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- return NULL;
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-}
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-
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-static void vring_unmap(void *buffer, bool is_write)
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-{
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- ram_addr_t addr;
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- MemoryRegion *mr;
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-
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- mr = qemu_ram_addr_from_host(buffer, &addr);
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- memory_region_unref(mr);
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-}
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-
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-/* Map the guest's vring to host memory */
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-bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
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-{
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- struct vring *vr = &vring->vr;
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- hwaddr addr;
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- hwaddr size;
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- void *ptr;
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-
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- vring->broken = false;
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- vr->num = virtio_queue_get_num(vdev, n);
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-
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- addr = virtio_queue_get_desc_addr(vdev, n);
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- size = virtio_queue_get_desc_size(vdev, n);
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- /* Map the descriptor area as read only */
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- ptr = vring_map(&vring->mr_desc, addr, size, NULL, false);
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- if (!ptr) {
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- error_report("Failed to map 0x%" HWADDR_PRIx " byte for vring desc "
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- "at 0x%" HWADDR_PRIx,
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- size, addr);
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- goto out_err_desc;
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- }
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- vr->desc = ptr;
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-
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- addr = virtio_queue_get_avail_addr(vdev, n);
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- size = virtio_queue_get_avail_size(vdev, n);
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- /* Add the size of the used_event_idx */
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- size += sizeof(uint16_t);
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- /* Map the driver area as read only */
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- ptr = vring_map(&vring->mr_avail, addr, size, NULL, false);
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- if (!ptr) {
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- error_report("Failed to map 0x%" HWADDR_PRIx " byte for vring avail "
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- "at 0x%" HWADDR_PRIx,
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- size, addr);
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- goto out_err_avail;
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- }
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- vr->avail = ptr;
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-
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- addr = virtio_queue_get_used_addr(vdev, n);
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- size = virtio_queue_get_used_size(vdev, n);
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- /* Add the size of the avail_event_idx */
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- size += sizeof(uint16_t);
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- /* Map the device area as read-write */
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- ptr = vring_map(&vring->mr_used, addr, size, NULL, true);
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- if (!ptr) {
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- error_report("Failed to map 0x%" HWADDR_PRIx " byte for vring used "
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- "at 0x%" HWADDR_PRIx,
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- size, addr);
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- goto out_err_used;
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- }
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- vr->used = ptr;
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-
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- vring->last_avail_idx = virtio_queue_get_last_avail_idx(vdev, n);
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- vring->last_used_idx = vring_get_used_idx(vdev, vring);
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- vring->signalled_used = 0;
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- vring->signalled_used_valid = false;
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-
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- trace_vring_setup(virtio_queue_get_ring_addr(vdev, n),
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- vring->vr.desc, vring->vr.avail, vring->vr.used);
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- return true;
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-
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-out_err_used:
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- memory_region_unref(vring->mr_avail);
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-out_err_avail:
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- memory_region_unref(vring->mr_desc);
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-out_err_desc:
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- vring->broken = true;
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- return false;
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-}
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-
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-void vring_teardown(Vring *vring, VirtIODevice *vdev, int n)
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-{
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- virtio_queue_set_last_avail_idx(vdev, n, vring->last_avail_idx);
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- virtio_queue_invalidate_signalled_used(vdev, n);
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-
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- memory_region_unref(vring->mr_desc);
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- memory_region_unref(vring->mr_avail);
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- memory_region_unref(vring->mr_used);
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-}
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-
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-/* Disable guest->host notifies */
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-void vring_disable_notification(VirtIODevice *vdev, Vring *vring)
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-{
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- if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
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- vring_set_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY);
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- }
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-}
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-
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-/* Enable guest->host notifies
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- *
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- * Return true if the vring is empty, false if there are more requests.
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- */
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-bool vring_enable_notification(VirtIODevice *vdev, Vring *vring)
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-{
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- if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
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- vring_avail_event(&vring->vr) = vring->vr.avail->idx;
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- } else {
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- vring_clear_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY);
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- }
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- smp_mb(); /* ensure update is seen before reading avail_idx */
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- return !vring_more_avail(vdev, vring);
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-}
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-
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-/* This is stolen from linux/drivers/vhost/vhost.c:vhost_notify() */
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-bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
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-{
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- uint16_t old, new;
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- bool v;
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- /* Flush out used index updates. This is paired
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- * with the barrier that the Guest executes when enabling
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- * interrupts. */
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- smp_mb();
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-
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- if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
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- unlikely(!vring_more_avail(vdev, vring))) {
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- return true;
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- }
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-
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- if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
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- return !(vring_get_avail_flags(vdev, vring) &
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- VRING_AVAIL_F_NO_INTERRUPT);
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- }
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- old = vring->signalled_used;
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- v = vring->signalled_used_valid;
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- new = vring->signalled_used = vring->last_used_idx;
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- vring->signalled_used_valid = true;
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-
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- if (unlikely(!v)) {
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- return true;
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- }
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-
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- return vring_need_event(virtio_tswap16(vdev, vring_used_event(&vring->vr)),
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- new, old);
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-}
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-
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-typedef struct VirtQueueCurrentElement {
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- unsigned in_num;
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- unsigned out_num;
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- hwaddr addr[VIRTQUEUE_MAX_SIZE];
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- struct iovec iov[VIRTQUEUE_MAX_SIZE];
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-} VirtQueueCurrentElement;
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-
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-static int get_desc(Vring *vring, VirtQueueCurrentElement *elem,
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- struct vring_desc *desc)
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-{
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- unsigned *num;
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- struct iovec *iov;
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- hwaddr *addr;
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- MemoryRegion *mr;
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- hwaddr len;
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-
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- if (desc->flags & VRING_DESC_F_WRITE) {
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- num = &elem->in_num;
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- iov = &elem->iov[elem->out_num + *num];
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- addr = &elem->addr[elem->out_num + *num];
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- } else {
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- num = &elem->out_num;
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- iov = &elem->iov[*num];
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- addr = &elem->addr[*num];
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-
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- /* If it's an output descriptor, they're all supposed
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- * to come before any input descriptors. */
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- if (unlikely(elem->in_num)) {
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- error_report("Descriptor has out after in");
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- return -EFAULT;
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- }
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- }
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-
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- while (desc->len) {
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- /* Stop for now if there are not enough iovecs available. */
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- if (*num >= VIRTQUEUE_MAX_SIZE) {
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- error_report("Invalid SG num: %u", *num);
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- return -EFAULT;
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- }
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-
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- iov->iov_base = vring_map(&mr, desc->addr, desc->len, &len,
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- desc->flags & VRING_DESC_F_WRITE);
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- if (!iov->iov_base) {
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- error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
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- (uint64_t)desc->addr, desc->len);
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- return -EFAULT;
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- }
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-
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- /* The MemoryRegion is looked up again and unref'ed later, leave the
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- * ref in place. */
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- (iov++)->iov_len = len;
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- *addr++ = desc->addr;
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- desc->len -= len;
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- desc->addr += len;
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- *num += 1;
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- }
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-
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- return 0;
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-}
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-
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-static void copy_in_vring_desc(VirtIODevice *vdev,
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- const struct vring_desc *guest,
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- struct vring_desc *host)
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-{
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- host->addr = virtio_ldq_p(vdev, &guest->addr);
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- host->len = virtio_ldl_p(vdev, &guest->len);
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- host->flags = virtio_lduw_p(vdev, &guest->flags);
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- host->next = virtio_lduw_p(vdev, &guest->next);
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-}
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-
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-static bool read_vring_desc(VirtIODevice *vdev,
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- hwaddr guest,
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- struct vring_desc *host)
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-{
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- if (address_space_read(&address_space_memory, guest, MEMTXATTRS_UNSPECIFIED,
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- (uint8_t *)host, sizeof *host)) {
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- return false;
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- }
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- host->addr = virtio_tswap64(vdev, host->addr);
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- host->len = virtio_tswap32(vdev, host->len);
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- host->flags = virtio_tswap16(vdev, host->flags);
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- host->next = virtio_tswap16(vdev, host->next);
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- return true;
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-}
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-
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-/* This is stolen from linux/drivers/vhost/vhost.c. */
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-static int get_indirect(VirtIODevice *vdev, Vring *vring,
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- VirtQueueCurrentElement *cur_elem,
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- struct vring_desc *indirect)
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-{
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- struct vring_desc desc;
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- unsigned int i = 0, count, found = 0;
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- int ret;
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-
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- /* Sanity check */
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- if (unlikely(indirect->len % sizeof(desc))) {
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- error_report("Invalid length in indirect descriptor: "
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- "len %#x not multiple of %#zx",
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- indirect->len, sizeof(desc));
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- vring->broken = true;
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- return -EFAULT;
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- }
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-
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- count = indirect->len / sizeof(desc);
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- /* Buffers are chained via a 16 bit next field, so
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- * we can have at most 2^16 of these. */
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- if (unlikely(count > USHRT_MAX + 1)) {
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- error_report("Indirect buffer length too big: %d", indirect->len);
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- vring->broken = true;
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- return -EFAULT;
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- }
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-
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- do {
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- /* Translate indirect descriptor */
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- if (!read_vring_desc(vdev, indirect->addr + found * sizeof(desc),
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- &desc)) {
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- error_report("Failed to read indirect descriptor "
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- "addr %#" PRIx64 " len %zu",
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- (uint64_t)indirect->addr + found * sizeof(desc),
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- sizeof(desc));
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- vring->broken = true;
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- return -EFAULT;
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- }
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-
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- /* Ensure descriptor has been loaded before accessing fields */
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- barrier(); /* read_barrier_depends(); */
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-
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- if (unlikely(++found > count)) {
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- error_report("Loop detected: last one at %u "
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- "indirect size %u", i, count);
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- vring->broken = true;
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- return -EFAULT;
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- }
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-
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- if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) {
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- error_report("Nested indirect descriptor");
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- vring->broken = true;
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- return -EFAULT;
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- }
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-
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- ret = get_desc(vring, cur_elem, &desc);
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- if (ret < 0) {
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- vring->broken |= (ret == -EFAULT);
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- return ret;
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- }
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- i = desc.next;
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- } while (desc.flags & VRING_DESC_F_NEXT);
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- return 0;
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-}
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-
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-static void vring_unmap_element(VirtQueueElement *elem)
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-{
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- int i;
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-
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- /* This assumes that the iovecs, if changed, are never moved past
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- * the end of the valid area. This is true if iovec manipulations
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- * are done with iov_discard_front and iov_discard_back.
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- */
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- for (i = 0; i < elem->out_num; i++) {
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- vring_unmap(elem->out_sg[i].iov_base, false);
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- }
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-
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- for (i = 0; i < elem->in_num; i++) {
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- vring_unmap(elem->in_sg[i].iov_base, true);
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- }
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-}
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-
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-/* This looks in the virtqueue and for the first available buffer, and converts
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- * it to an iovec for convenient access. Since descriptors consist of some
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- * number of output then some number of input descriptors, it's actually two
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|
|
- * 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.
|
|
|
- */
|
|
|
-void *vring_pop(VirtIODevice *vdev, Vring *vring, size_t sz)
|
|
|
-{
|
|
|
- struct vring_desc desc;
|
|
|
- unsigned int i, head, found = 0, num = vring->vr.num;
|
|
|
- uint16_t avail_idx, last_avail_idx;
|
|
|
- VirtQueueCurrentElement cur_elem;
|
|
|
- VirtQueueElement *elem = NULL;
|
|
|
- int ret;
|
|
|
-
|
|
|
- /* If there was a fatal error then refuse operation */
|
|
|
- if (vring->broken) {
|
|
|
- ret = -EFAULT;
|
|
|
- goto out;
|
|
|
- }
|
|
|
-
|
|
|
- cur_elem.in_num = cur_elem.out_num = 0;
|
|
|
-
|
|
|
- /* 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);
|
|
|
-
|
|
|
- /* 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, &cur_elem, &desc);
|
|
|
- if (ret < 0) {
|
|
|
- goto out;
|
|
|
- }
|
|
|
- continue;
|
|
|
- }
|
|
|
-
|
|
|
- ret = get_desc(vring, &cur_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_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
|
|
|
- vring_avail_event(&vring->vr) =
|
|
|
- virtio_tswap16(vdev, vring->last_avail_idx);
|
|
|
- }
|
|
|
-
|
|
|
- /* Now copy what we have collected and mapped */
|
|
|
- elem = virtqueue_alloc_element(sz, cur_elem.out_num, cur_elem.in_num);
|
|
|
- elem->index = head;
|
|
|
- for (i = 0; i < cur_elem.out_num; i++) {
|
|
|
- elem->out_addr[i] = cur_elem.addr[i];
|
|
|
- elem->out_sg[i] = cur_elem.iov[i];
|
|
|
- }
|
|
|
- for (i = 0; i < cur_elem.in_num; i++) {
|
|
|
- elem->in_addr[i] = cur_elem.addr[cur_elem.out_num + i];
|
|
|
- elem->in_sg[i] = cur_elem.iov[cur_elem.out_num + i];
|
|
|
- }
|
|
|
-
|
|
|
- return elem;
|
|
|
-
|
|
|
-out:
|
|
|
- assert(ret < 0);
|
|
|
- if (ret == -EFAULT) {
|
|
|
- vring->broken = true;
|
|
|
- }
|
|
|
-
|
|
|
- for (i = 0; i < cur_elem.out_num + cur_elem.in_num; i++) {
|
|
|
- vring_unmap(cur_elem.iov[i].iov_base, false);
|
|
|
- }
|
|
|
-
|
|
|
- g_free(elem);
|
|
|
- return NULL;
|
|
|
-}
|
|
|
-
|
|
|
-/* 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;
|
|
|
- }
|
|
|
-}
|