Upon receiving an event channel notification from the frontend, schedule the bottom half. From the bottom half, read one request from the ring, create a pdu and call pdu_submit to handle it. For now, only handle one request per ring at a time. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> CC: anthony.perard@citrix.com CC: jgross@suse.com CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> CC: Greg Kurz <groug@kaod.org>
327 lines
9.8 KiB
C
327 lines
9.8 KiB
C
/*
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* Xen 9p backend
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*
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* Copyright Aporeto 2017
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*
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* Authors:
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* Stefano Stabellini <stefano@aporeto.com>
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*
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*/
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#include "qemu/osdep.h"
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#include "hw/hw.h"
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#include "hw/9pfs/9p.h"
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#include "hw/xen/xen_backend.h"
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#include "hw/9pfs/xen-9pfs.h"
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#include "qemu/config-file.h"
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#include "fsdev/qemu-fsdev.h"
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#define VERSIONS "1"
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#define MAX_RINGS 8
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#define MAX_RING_ORDER 8
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typedef struct Xen9pfsRing {
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struct Xen9pfsDev *priv;
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int ref;
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xenevtchn_handle *evtchndev;
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int evtchn;
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int local_port;
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int ring_order;
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struct xen_9pfs_data_intf *intf;
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unsigned char *data;
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struct xen_9pfs_data ring;
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struct iovec *sg;
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QEMUBH *bh;
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/* local copies, so that we can read/write PDU data directly from
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* the ring */
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RING_IDX out_cons, out_size, in_cons;
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bool inprogress;
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} Xen9pfsRing;
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typedef struct Xen9pfsDev {
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struct XenDevice xendev; /* must be first */
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V9fsState state;
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char *path;
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char *security_model;
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char *tag;
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char *id;
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int num_rings;
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Xen9pfsRing *rings;
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} Xen9pfsDev;
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static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu,
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size_t offset,
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const char *fmt,
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va_list ap)
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{
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return 0;
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}
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static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
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size_t offset,
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const char *fmt,
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va_list ap)
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{
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return 0;
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}
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static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu,
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struct iovec **piov,
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unsigned int *pniov)
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{
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}
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static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu,
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struct iovec **piov,
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unsigned int *pniov,
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size_t size)
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{
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}
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static void xen_9pfs_push_and_notify(V9fsPDU *pdu)
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{
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}
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static const struct V9fsTransport xen_9p_transport = {
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.pdu_vmarshal = xen_9pfs_pdu_vmarshal,
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.pdu_vunmarshal = xen_9pfs_pdu_vunmarshal,
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.init_in_iov_from_pdu = xen_9pfs_init_in_iov_from_pdu,
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.init_out_iov_from_pdu = xen_9pfs_init_out_iov_from_pdu,
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.push_and_notify = xen_9pfs_push_and_notify,
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};
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static int xen_9pfs_init(struct XenDevice *xendev)
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{
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return 0;
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}
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static int xen_9pfs_receive(Xen9pfsRing *ring)
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{
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P9MsgHeader h;
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RING_IDX cons, prod, masked_prod, masked_cons;
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V9fsPDU *pdu;
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if (ring->inprogress) {
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return 0;
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}
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cons = ring->intf->out_cons;
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prod = ring->intf->out_prod;
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xen_rmb();
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if (xen_9pfs_queued(prod, cons, XEN_FLEX_RING_SIZE(ring->ring_order)) <
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sizeof(h)) {
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return 0;
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}
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ring->inprogress = true;
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masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order));
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masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order));
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xen_9pfs_read_packet((uint8_t *) &h, ring->ring.out, sizeof(h),
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masked_prod, &masked_cons,
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XEN_FLEX_RING_SIZE(ring->ring_order));
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/* cannot fail, because we only handle one request per ring at a time */
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pdu = pdu_alloc(&ring->priv->state);
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pdu->size = le32_to_cpu(h.size_le);
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pdu->id = h.id;
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pdu->tag = le32_to_cpu(h.tag_le);
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ring->out_size = le32_to_cpu(h.size_le);
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ring->out_cons = cons + le32_to_cpu(h.size_le);
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qemu_co_queue_init(&pdu->complete);
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pdu_submit(pdu);
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return 0;
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}
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static void xen_9pfs_bh(void *opaque)
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{
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Xen9pfsRing *ring = opaque;
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xen_9pfs_receive(ring);
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}
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static void xen_9pfs_evtchn_event(void *opaque)
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{
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Xen9pfsRing *ring = opaque;
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evtchn_port_t port;
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port = xenevtchn_pending(ring->evtchndev);
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xenevtchn_unmask(ring->evtchndev, port);
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qemu_bh_schedule(ring->bh);
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}
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static int xen_9pfs_free(struct XenDevice *xendev)
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{
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int i;
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Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev);
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g_free(xen_9pdev->id);
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g_free(xen_9pdev->tag);
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g_free(xen_9pdev->path);
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g_free(xen_9pdev->security_model);
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for (i = 0; i < xen_9pdev->num_rings; i++) {
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if (xen_9pdev->rings[i].data != NULL) {
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xengnttab_unmap(xen_9pdev->xendev.gnttabdev,
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xen_9pdev->rings[i].data,
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(1 << xen_9pdev->rings[i].ring_order));
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}
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if (xen_9pdev->rings[i].intf != NULL) {
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xengnttab_unmap(xen_9pdev->xendev.gnttabdev,
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xen_9pdev->rings[i].intf,
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1);
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}
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if (xen_9pdev->rings[i].evtchndev > 0) {
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qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
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NULL, NULL, NULL);
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xenevtchn_unbind(xen_9pdev->rings[i].evtchndev,
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xen_9pdev->rings[i].local_port);
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}
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if (xen_9pdev->rings[i].bh != NULL) {
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qemu_bh_delete(xen_9pdev->rings[i].bh);
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}
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}
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g_free(xen_9pdev->rings);
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return 0;
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}
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static int xen_9pfs_connect(struct XenDevice *xendev)
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{
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int i;
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Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev);
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V9fsState *s = &xen_9pdev->state;
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QemuOpts *fsdev;
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if (xenstore_read_fe_int(&xen_9pdev->xendev, "num-rings",
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&xen_9pdev->num_rings) == -1 ||
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xen_9pdev->num_rings > MAX_RINGS || xen_9pdev->num_rings < 1) {
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return -1;
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}
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xen_9pdev->rings = g_malloc0(xen_9pdev->num_rings * sizeof(Xen9pfsRing));
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for (i = 0; i < xen_9pdev->num_rings; i++) {
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char *str;
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int ring_order;
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xen_9pdev->rings[i].priv = xen_9pdev;
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xen_9pdev->rings[i].evtchn = -1;
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xen_9pdev->rings[i].local_port = -1;
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str = g_strdup_printf("ring-ref%u", i);
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if (xenstore_read_fe_int(&xen_9pdev->xendev, str,
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&xen_9pdev->rings[i].ref) == -1) {
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goto out;
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}
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g_free(str);
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str = g_strdup_printf("event-channel-%u", i);
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if (xenstore_read_fe_int(&xen_9pdev->xendev, str,
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&xen_9pdev->rings[i].evtchn) == -1) {
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goto out;
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}
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g_free(str);
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xen_9pdev->rings[i].intf = xengnttab_map_grant_ref(
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xen_9pdev->xendev.gnttabdev,
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xen_9pdev->xendev.dom,
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xen_9pdev->rings[i].ref,
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PROT_READ | PROT_WRITE);
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if (!xen_9pdev->rings[i].intf) {
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goto out;
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}
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ring_order = xen_9pdev->rings[i].intf->ring_order;
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if (ring_order > MAX_RING_ORDER) {
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goto out;
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}
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xen_9pdev->rings[i].ring_order = ring_order;
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xen_9pdev->rings[i].data = xengnttab_map_domain_grant_refs(
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xen_9pdev->xendev.gnttabdev,
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(1 << ring_order),
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xen_9pdev->xendev.dom,
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xen_9pdev->rings[i].intf->ref,
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PROT_READ | PROT_WRITE);
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if (!xen_9pdev->rings[i].data) {
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goto out;
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}
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xen_9pdev->rings[i].ring.in = xen_9pdev->rings[i].data;
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xen_9pdev->rings[i].ring.out = xen_9pdev->rings[i].data +
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XEN_FLEX_RING_SIZE(ring_order);
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xen_9pdev->rings[i].bh = qemu_bh_new(xen_9pfs_bh, &xen_9pdev->rings[i]);
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xen_9pdev->rings[i].out_cons = 0;
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xen_9pdev->rings[i].out_size = 0;
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xen_9pdev->rings[i].inprogress = false;
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xen_9pdev->rings[i].evtchndev = xenevtchn_open(NULL, 0);
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if (xen_9pdev->rings[i].evtchndev == NULL) {
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goto out;
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}
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fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), F_SETFD, FD_CLOEXEC);
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xen_9pdev->rings[i].local_port = xenevtchn_bind_interdomain
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(xen_9pdev->rings[i].evtchndev,
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xendev->dom,
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xen_9pdev->rings[i].evtchn);
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if (xen_9pdev->rings[i].local_port == -1) {
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xen_pv_printf(xendev, 0,
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"xenevtchn_bind_interdomain failed port=%d\n",
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xen_9pdev->rings[i].evtchn);
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goto out;
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}
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xen_pv_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
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qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
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xen_9pfs_evtchn_event, NULL, &xen_9pdev->rings[i]);
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}
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xen_9pdev->security_model = xenstore_read_be_str(xendev, "security_model");
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xen_9pdev->path = xenstore_read_be_str(xendev, "path");
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xen_9pdev->id = s->fsconf.fsdev_id =
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g_strdup_printf("xen9p%d", xendev->dev);
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xen_9pdev->tag = s->fsconf.tag = xenstore_read_fe_str(xendev, "tag");
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v9fs_register_transport(s, &xen_9p_transport);
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fsdev = qemu_opts_create(qemu_find_opts("fsdev"),
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s->fsconf.tag,
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1, NULL);
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qemu_opt_set(fsdev, "fsdriver", "local", NULL);
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qemu_opt_set(fsdev, "path", xen_9pdev->path, NULL);
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qemu_opt_set(fsdev, "security_model", xen_9pdev->security_model, NULL);
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qemu_opts_set_id(fsdev, s->fsconf.fsdev_id);
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qemu_fsdev_add(fsdev);
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v9fs_device_realize_common(s, NULL);
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return 0;
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out:
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xen_9pfs_free(xendev);
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return -1;
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}
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static void xen_9pfs_alloc(struct XenDevice *xendev)
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{
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xenstore_write_be_str(xendev, "versions", VERSIONS);
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xenstore_write_be_int(xendev, "max-rings", MAX_RINGS);
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xenstore_write_be_int(xendev, "max-ring-page-order", MAX_RING_ORDER);
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}
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static void xen_9pfs_disconnect(struct XenDevice *xendev)
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{
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/* Dynamic hotplug of PV filesystems at runtime is not supported. */
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}
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struct XenDevOps xen_9pfs_ops = {
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.size = sizeof(Xen9pfsDev),
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.flags = DEVOPS_FLAG_NEED_GNTDEV,
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.alloc = xen_9pfs_alloc,
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.init = xen_9pfs_init,
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.initialise = xen_9pfs_connect,
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.disconnect = xen_9pfs_disconnect,
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.free = xen_9pfs_free,
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};
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