Not all 9pfs transports share memory between request and response. For those who don't, it is necessary to know how much memory is required in the response. Split the existing init_iov_from_pdu function in two: init_out_iov_from_pdu (for writes) and init_in_iov_from_pdu (for reads). init_in_iov_from_pdu takes an additional size parameter to specify the memory required for the response message. Signed-off-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Greg Kurz <groug@kaod.org> Signed-off-by: Greg Kurz <groug@kaod.org>
251 lines
7 KiB
C
251 lines
7 KiB
C
/*
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* Virtio 9p backend
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*
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* Copyright IBM, Corp. 2010
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu/osdep.h"
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#include "hw/virtio/virtio.h"
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#include "qemu/sockets.h"
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#include "virtio-9p.h"
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#include "fsdev/qemu-fsdev.h"
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#include "coth.h"
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#include "hw/virtio/virtio-access.h"
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#include "qemu/iov.h"
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static const struct V9fsTransport virtio_9p_transport;
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static void virtio_9p_push_and_notify(V9fsPDU *pdu)
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{
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V9fsState *s = pdu->s;
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V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
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VirtQueueElement *elem = v->elems[pdu->idx];
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/* push onto queue and notify */
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virtqueue_push(v->vq, elem, pdu->size);
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g_free(elem);
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v->elems[pdu->idx] = NULL;
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/* FIXME: we should batch these completions */
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virtio_notify(VIRTIO_DEVICE(v), v->vq);
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}
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static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
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{
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V9fsVirtioState *v = (V9fsVirtioState *)vdev;
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V9fsState *s = &v->state;
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V9fsPDU *pdu;
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ssize_t len;
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VirtQueueElement *elem;
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while ((pdu = pdu_alloc(s))) {
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struct {
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uint32_t size_le;
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uint8_t id;
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uint16_t tag_le;
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} QEMU_PACKED out;
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elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
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if (!elem) {
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goto out_free_pdu;
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}
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if (elem->in_num == 0) {
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virtio_error(vdev,
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"The guest sent a VirtFS request without space for "
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"the reply");
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goto out_free_req;
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}
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QEMU_BUILD_BUG_ON(sizeof(out) != 7);
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v->elems[pdu->idx] = elem;
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len = iov_to_buf(elem->out_sg, elem->out_num, 0,
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&out, sizeof(out));
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if (len != sizeof(out)) {
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virtio_error(vdev, "The guest sent a malformed VirtFS request: "
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"header size is %zd, should be 7", len);
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goto out_free_req;
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}
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pdu->size = le32_to_cpu(out.size_le);
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pdu->id = out.id;
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pdu->tag = le16_to_cpu(out.tag_le);
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qemu_co_queue_init(&pdu->complete);
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pdu_submit(pdu);
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}
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return;
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out_free_req:
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virtqueue_detach_element(vq, elem, 0);
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g_free(elem);
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out_free_pdu:
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pdu_free(pdu);
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}
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static uint64_t virtio_9p_get_features(VirtIODevice *vdev, uint64_t features,
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Error **errp)
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{
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virtio_add_feature(&features, VIRTIO_9P_MOUNT_TAG);
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return features;
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}
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static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
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{
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int len;
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struct virtio_9p_config *cfg;
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V9fsVirtioState *v = VIRTIO_9P(vdev);
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V9fsState *s = &v->state;
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len = strlen(s->tag);
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cfg = g_malloc0(sizeof(struct virtio_9p_config) + len);
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virtio_stw_p(vdev, &cfg->tag_len, len);
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/* We don't copy the terminating null to config space */
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memcpy(cfg->tag, s->tag, len);
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memcpy(config, cfg, v->config_size);
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g_free(cfg);
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}
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static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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V9fsVirtioState *v = VIRTIO_9P(dev);
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V9fsState *s = &v->state;
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if (v9fs_device_realize_common(s, errp)) {
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goto out;
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}
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v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
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virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
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v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
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v9fs_register_transport(s, &virtio_9p_transport);
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out:
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return;
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}
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static void virtio_9p_device_unrealize(DeviceState *dev, Error **errp)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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V9fsVirtioState *v = VIRTIO_9P(dev);
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V9fsState *s = &v->state;
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virtio_cleanup(vdev);
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v9fs_device_unrealize_common(s, errp);
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}
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static void virtio_9p_reset(VirtIODevice *vdev)
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{
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V9fsVirtioState *v = (V9fsVirtioState *)vdev;
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v9fs_reset(&v->state);
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}
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static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
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const char *fmt, va_list ap)
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{
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V9fsState *s = pdu->s;
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V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
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VirtQueueElement *elem = v->elems[pdu->idx];
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return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
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}
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static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
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const char *fmt, va_list ap)
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{
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V9fsState *s = pdu->s;
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V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
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VirtQueueElement *elem = v->elems[pdu->idx];
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return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
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}
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/* The size parameter is used by other transports. Do not drop it. */
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static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
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unsigned int *pniov, size_t size)
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{
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V9fsState *s = pdu->s;
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V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
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VirtQueueElement *elem = v->elems[pdu->idx];
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*piov = elem->in_sg;
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*pniov = elem->in_num;
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}
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static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
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unsigned int *pniov)
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{
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V9fsState *s = pdu->s;
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V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
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VirtQueueElement *elem = v->elems[pdu->idx];
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*piov = elem->out_sg;
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*pniov = elem->out_num;
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}
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static const struct V9fsTransport virtio_9p_transport = {
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.pdu_vmarshal = virtio_pdu_vmarshal,
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.pdu_vunmarshal = virtio_pdu_vunmarshal,
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.init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
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.init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
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.push_and_notify = virtio_9p_push_and_notify,
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};
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/* virtio-9p device */
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static const VMStateDescription vmstate_virtio_9p = {
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.name = "virtio-9p",
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.minimum_version_id = 1,
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.version_id = 1,
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.fields = (VMStateField[]) {
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VMSTATE_VIRTIO_DEVICE,
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VMSTATE_END_OF_LIST()
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},
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};
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static Property virtio_9p_properties[] = {
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DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
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DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
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DEFINE_PROP_END_OF_LIST(),
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};
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static void virtio_9p_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
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dc->props = virtio_9p_properties;
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dc->vmsd = &vmstate_virtio_9p;
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set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
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vdc->realize = virtio_9p_device_realize;
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vdc->unrealize = virtio_9p_device_unrealize;
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vdc->get_features = virtio_9p_get_features;
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vdc->get_config = virtio_9p_get_config;
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vdc->reset = virtio_9p_reset;
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}
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static const TypeInfo virtio_device_info = {
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.name = TYPE_VIRTIO_9P,
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.parent = TYPE_VIRTIO_DEVICE,
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.instance_size = sizeof(V9fsVirtioState),
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.class_init = virtio_9p_class_init,
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};
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static void virtio_9p_register_types(void)
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{
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type_register_static(&virtio_device_info);
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}
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type_init(virtio_9p_register_types)
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