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143 lines
4.3 KiB
C
143 lines
4.3 KiB
C
/*
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* vhost shadow virtqueue
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*
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* SPDX-FileCopyrightText: Red Hat, Inc. 2021
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* SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#ifndef VHOST_SHADOW_VIRTQUEUE_H
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#define VHOST_SHADOW_VIRTQUEUE_H
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#include "qemu/event_notifier.h"
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#include "hw/virtio/virtio.h"
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#include "standard-headers/linux/vhost_types.h"
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#include "hw/virtio/vhost-iova-tree.h"
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typedef struct SVQDescState {
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VirtQueueElement *elem;
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/*
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* Number of descriptors exposed to the device. May or may not match
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* guest's
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*/
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unsigned int ndescs;
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} SVQDescState;
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typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
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/**
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* Callback to handle an avail buffer.
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*
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* @svq: Shadow virtqueue
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* @elem: Element placed in the queue by the guest
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* @vq_callback_opaque: Opaque
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*
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* Returns 0 if the vq is running as expected.
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*
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* Note that ownership of elem is transferred to the callback.
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*/
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typedef int (*VirtQueueAvailCallback)(VhostShadowVirtqueue *svq,
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VirtQueueElement *elem,
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void *vq_callback_opaque);
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typedef struct VhostShadowVirtqueueOps {
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VirtQueueAvailCallback avail_handler;
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} VhostShadowVirtqueueOps;
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/* Shadow virtqueue to relay notifications */
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typedef struct VhostShadowVirtqueue {
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/* Shadow vring */
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struct vring vring;
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/* Shadow kick notifier, sent to vhost */
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EventNotifier hdev_kick;
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/* Shadow call notifier, sent to vhost */
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EventNotifier hdev_call;
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/*
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* Borrowed virtqueue's guest to host notifier. To borrow it in this event
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* notifier allows to recover the VhostShadowVirtqueue from the event loop
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* easily. If we use the VirtQueue's one, we don't have an easy way to
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* retrieve VhostShadowVirtqueue.
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*
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* So shadow virtqueue must not clean it, or we would lose VirtQueue one.
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*/
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EventNotifier svq_kick;
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/* Guest's call notifier, where the SVQ calls guest. */
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EventNotifier svq_call;
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/* Virtio queue shadowing */
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VirtQueue *vq;
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/* Virtio device */
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VirtIODevice *vdev;
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/* IOVA mapping */
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VhostIOVATree *iova_tree;
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/* SVQ vring descriptors state */
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SVQDescState *desc_state;
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/* Next VirtQueue element that guest made available */
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VirtQueueElement *next_guest_avail_elem;
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/*
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* Backup next field for each descriptor so we can recover securely, not
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* needing to trust the device access.
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*/
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uint16_t *desc_next;
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/* Caller callbacks */
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const VhostShadowVirtqueueOps *ops;
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/* Caller callbacks opaque */
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void *ops_opaque;
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/* Next head to expose to the device */
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uint16_t shadow_avail_idx;
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/* Next free descriptor */
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uint16_t free_head;
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/* Last seen used idx */
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uint16_t shadow_used_idx;
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/* Next head to consume from the device */
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uint16_t last_used_idx;
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/* Size of SVQ vring free descriptors */
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uint16_t num_free;
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} VhostShadowVirtqueue;
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bool vhost_svq_valid_features(uint64_t features, Error **errp);
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uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq);
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void vhost_svq_push_elem(VhostShadowVirtqueue *svq,
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const VirtQueueElement *elem, uint32_t len);
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int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
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size_t out_num, const struct iovec *in_sg, size_t in_num,
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VirtQueueElement *elem);
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size_t vhost_svq_poll(VhostShadowVirtqueue *svq, size_t num);
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void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
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void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
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void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
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struct vhost_vring_addr *addr);
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size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
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size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
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void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
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VirtQueue *vq, VhostIOVATree *iova_tree);
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void vhost_svq_stop(VhostShadowVirtqueue *svq);
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VhostShadowVirtqueue *vhost_svq_new(const VhostShadowVirtqueueOps *ops,
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void *ops_opaque);
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void vhost_svq_free(gpointer vq);
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G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
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#endif
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