qmp: add QMP command x-query-virtio-queue-element
This new command shows the information of a VirtQueue element. [Note: Up until v10 of this patch series, virtio.json had many (15+) enums defined (e.g. decoded device features, statuses, etc.). In v10 most of these enums were removed and replaced with string literals. By doing this we get (1) simpler schema, (2) smaller generated code, and (3) less maintenance burden for when new things are added (e.g. devices, device features, etc.).] Signed-off-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com> Message-Id: <1660220684-24909-6-git-send-email-jonah.palmer@oracle.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Laurent Vivier
Michael S. Tsirkin
parent
07536ddda7
commit
1ee7bb5bef
@ -31,3 +31,12 @@ VirtQueueStatus *qmp_x_query_virtio_queue_status(const char *path,
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{
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return qmp_virtio_unsupported(errp);
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}
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VirtioQueueElement *qmp_x_query_virtio_queue_element(const char *path,
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uint16_t queue,
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bool has_index,
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uint16_t index,
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Error **errp)
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{
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return qmp_virtio_unsupported(errp);
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}
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@ -823,6 +823,19 @@ static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
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address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
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}
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/* Called within rcu_read_lock(). */
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static inline uint16_t vring_used_flags(VirtQueue *vq)
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{
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VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
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hwaddr pa = offsetof(VRingUsed, flags);
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if (!caches) {
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return 0;
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}
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return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
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}
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/* Called within rcu_read_lock(). */
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static uint16_t vring_used_idx(VirtQueue *vq)
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{
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@ -4782,6 +4795,147 @@ VirtQueueStatus *qmp_x_query_virtio_queue_status(const char *path,
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return status;
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}
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static strList *qmp_decode_vring_desc_flags(uint16_t flags)
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{
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strList *list = NULL;
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strList *node;
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int i;
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struct {
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uint16_t flag;
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const char *value;
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} map[] = {
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{ VRING_DESC_F_NEXT, "next" },
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{ VRING_DESC_F_WRITE, "write" },
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{ VRING_DESC_F_INDIRECT, "indirect" },
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{ 1 << VRING_PACKED_DESC_F_AVAIL, "avail" },
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{ 1 << VRING_PACKED_DESC_F_USED, "used" },
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{ 0, "" }
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};
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for (i = 0; map[i].flag; i++) {
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if ((map[i].flag & flags) == 0) {
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continue;
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}
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node = g_malloc0(sizeof(strList));
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node->value = g_strdup(map[i].value);
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node->next = list;
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list = node;
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}
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return list;
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}
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VirtioQueueElement *qmp_x_query_virtio_queue_element(const char *path,
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uint16_t queue,
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bool has_index,
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uint16_t index,
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Error **errp)
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{
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VirtIODevice *vdev;
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VirtQueue *vq;
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VirtioQueueElement *element = NULL;
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vdev = virtio_device_find(path);
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if (vdev == NULL) {
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error_setg(errp, "Path %s is not a VirtIO device", path);
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return NULL;
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}
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if (queue >= VIRTIO_QUEUE_MAX || !virtio_queue_get_num(vdev, queue)) {
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error_setg(errp, "Invalid virtqueue number %d", queue);
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return NULL;
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}
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vq = &vdev->vq[queue];
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if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
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error_setg(errp, "Packed ring not supported");
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return NULL;
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} else {
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unsigned int head, i, max;
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VRingMemoryRegionCaches *caches;
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MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
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MemoryRegionCache *desc_cache;
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VRingDesc desc;
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VirtioRingDescList *list = NULL;
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VirtioRingDescList *node;
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int rc; int ndescs;
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RCU_READ_LOCK_GUARD();
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max = vq->vring.num;
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if (!has_index) {
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head = vring_avail_ring(vq, vq->last_avail_idx % vq->vring.num);
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} else {
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head = vring_avail_ring(vq, index % vq->vring.num);
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}
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i = head;
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caches = vring_get_region_caches(vq);
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if (!caches) {
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error_setg(errp, "Region caches not initialized");
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return NULL;
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}
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if (caches->desc.len < max * sizeof(VRingDesc)) {
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error_setg(errp, "Cannot map descriptor ring");
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return NULL;
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}
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desc_cache = &caches->desc;
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vring_split_desc_read(vdev, &desc, desc_cache, i);
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if (desc.flags & VRING_DESC_F_INDIRECT) {
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int64_t len;
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len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
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desc.addr, desc.len, false);
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desc_cache = &indirect_desc_cache;
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if (len < desc.len) {
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error_setg(errp, "Cannot map indirect buffer");
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goto done;
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}
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max = desc.len / sizeof(VRingDesc);
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i = 0;
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vring_split_desc_read(vdev, &desc, desc_cache, i);
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}
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element = g_new0(VirtioQueueElement, 1);
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element->avail = g_new0(VirtioRingAvail, 1);
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element->used = g_new0(VirtioRingUsed, 1);
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element->name = g_strdup(vdev->name);
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element->index = head;
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element->avail->flags = vring_avail_flags(vq);
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element->avail->idx = vring_avail_idx(vq);
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element->avail->ring = head;
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element->used->flags = vring_used_flags(vq);
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element->used->idx = vring_used_idx(vq);
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ndescs = 0;
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do {
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/* A buggy driver may produce an infinite loop */
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if (ndescs >= max) {
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break;
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}
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node = g_new0(VirtioRingDescList, 1);
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node->value = g_new0(VirtioRingDesc, 1);
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node->value->addr = desc.addr;
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node->value->len = desc.len;
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node->value->flags = qmp_decode_vring_desc_flags(desc.flags);
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node->next = list;
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list = node;
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ndescs++;
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rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache,
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max, &i);
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} while (rc == VIRTQUEUE_READ_DESC_MORE);
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element->descs = list;
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done:
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address_space_cache_destroy(&indirect_desc_cache);
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}
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return element;
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}
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static const TypeInfo virtio_device_info = {
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.name = TYPE_VIRTIO_DEVICE,
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.parent = TYPE_DEVICE,
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197
qapi/virtio.json
197
qapi/virtio.json
@ -755,3 +755,200 @@
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'data': { 'path': 'str', 'queue': 'uint16' },
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'returns': 'VirtVhostQueueStatus',
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'features': [ 'unstable' ] }
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##
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# @VirtioRingDesc:
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#
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# Information regarding the vring descriptor area
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#
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# @addr: Guest physical address of the descriptor area
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#
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# @len: Length of the descriptor area
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#
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# @flags: List of descriptor flags
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#
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# Since: 7.1
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#
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##
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{ 'struct': 'VirtioRingDesc',
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'data': { 'addr': 'uint64',
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'len': 'uint32',
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'flags': [ 'str' ] } }
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##
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# @VirtioRingAvail:
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#
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# Information regarding the avail vring (a.k.a. driver area)
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#
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# @flags: VRingAvail flags
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#
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# @idx: VRingAvail index
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#
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# @ring: VRingAvail ring[] entry at provided index
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#
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# Since: 7.1
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#
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##
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{ 'struct': 'VirtioRingAvail',
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'data': { 'flags': 'uint16',
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'idx': 'uint16',
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'ring': 'uint16' } }
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##
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# @VirtioRingUsed:
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#
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# Information regarding the used vring (a.k.a. device area)
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#
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# @flags: VRingUsed flags
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#
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# @idx: VRingUsed index
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#
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# Since: 7.1
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#
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##
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{ 'struct': 'VirtioRingUsed',
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'data': { 'flags': 'uint16',
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'idx': 'uint16' } }
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##
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# @VirtioQueueElement:
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#
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# Information regarding a VirtQueue's VirtQueueElement including
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# descriptor, driver, and device areas
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#
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# @name: Name of the VirtIODevice that uses this VirtQueue
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#
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# @index: Index of the element in the queue
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#
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# @descs: List of descriptors (VirtioRingDesc)
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#
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# @avail: VRingAvail info
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#
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# @used: VRingUsed info
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#
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# Since: 7.1
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#
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##
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{ 'struct': 'VirtioQueueElement',
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'data': { 'name': 'str',
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'index': 'uint32',
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'descs': [ 'VirtioRingDesc' ],
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'avail': 'VirtioRingAvail',
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'used': 'VirtioRingUsed' } }
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##
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# @x-query-virtio-queue-element:
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#
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# Return the information about a VirtQueue's VirtQueueElement
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#
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# @path: VirtIODevice canonical QOM path
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#
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# @queue: VirtQueue index to examine
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#
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# @index: Index of the element in the queue
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# (default: head of the queue)
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#
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# Features:
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# @unstable: This command is meant for debugging.
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#
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# Returns: VirtioQueueElement information
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#
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# Since: 7.1
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#
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# Examples:
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#
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# 1. Introspect on virtio-net's VirtQueue 0 at index 5
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#
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# -> { "execute": "x-query-virtio-queue-element",
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# "arguments": { "path": "/machine/peripheral-anon/device[1]/virtio-backend",
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# "queue": 0,
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# "index": 5 }
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# }
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# <- { "return": {
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# "index": 5,
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# "name": "virtio-net",
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# "descs": [
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# {
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# "flags": ["write"],
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# "len": 1536,
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# "addr": 5257305600
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# }
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# ],
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# "avail": {
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# "idx": 256,
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# "flags": 0,
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# "ring": 5
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# },
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# "used": {
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# "idx": 13,
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# "flags": 0
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# }
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# }
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# }
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#
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# 2. Introspect on virtio-crypto's VirtQueue 1 at head
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#
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# -> { "execute": "x-query-virtio-queue-element",
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# "arguments": { "path": "/machine/peripheral/crypto0/virtio-backend",
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# "queue": 1 }
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# }
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# <- { "return": {
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# "index": 0,
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# "name": "virtio-crypto",
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# "descs": [
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# {
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# "flags": [],
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# "len": 0,
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# "addr": 8080268923184214134
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# }
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# ],
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# "avail": {
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# "idx": 280,
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# "flags": 0,
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# "ring": 0
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# },
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# "used": {
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# "idx": 280,
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# "flags": 0
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# }
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# }
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# }
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#
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# 3. Introspect on virtio-scsi's VirtQueue 2 at head
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#
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# -> { "execute": "x-query-virtio-queue-element",
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# "arguments": { "path": "/machine/peripheral-anon/device[2]/virtio-backend",
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# "queue": 2 }
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# }
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# <- { "return": {
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# "index": 19,
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# "name": "virtio-scsi",
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# "descs": [
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# {
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# "flags": ["used", "indirect", "write"],
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# "len": 4099327944,
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# "addr": 12055409292258155293
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# }
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# ],
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# "avail": {
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# "idx": 1147,
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# "flags": 0,
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# "ring": 19
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# },
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# "used": {
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# "idx": 280,
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# "flags": 0
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# }
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# }
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# }
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#
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##
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{ 'command': 'x-query-virtio-queue-element',
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'data': { 'path': 'str', 'queue': 'uint16', '*index': 'uint16' },
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'returns': 'VirtioQueueElement',
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'features': [ 'unstable' ] }
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