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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 5/9] xen/9pfs: connect to the frontend
On Wed, 15 Mar 2017, Greg Kurz wrote:
> On Mon, 13 Mar 2017 16:55:56 -0700
> Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote:
>
> > Write the limits of the backend to xenstore. Connect to the frontend.
> > Upon connection, allocate the rings according to the protocol
> > specification.
> >
> > Initialize a QEMUBH to schedule work upon receiving an event channel
> > notification from the frontend.
> >
> > Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
> > CC: anthony.perard@xxxxxxxxxx
> > CC: jgross@xxxxxxxx
> > CC: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> > CC: Greg Kurz <groug@xxxxxxxx>
> > ---
> > hw/9pfs/xen-9p-backend.c | 159
> > ++++++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 158 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> > index 35032d3..0e4a133 100644
> > --- a/hw/9pfs/xen-9p-backend.c
> > +++ b/hw/9pfs/xen-9p-backend.c
> > @@ -17,8 +17,35 @@
> > #include "qemu/config-file.h"
> > #include "fsdev/qemu-fsdev.h"
> >
> > +#define VERSIONS "1"
> > +#define MAX_RINGS 8
> > +#define MAX_RING_ORDER 8
> > +
> > +struct Xen9pfsRing {
> > + struct Xen9pfsDev *priv;
> > +
> > + int ref;
> > + xenevtchn_handle *evtchndev;
> > + int evtchn;
> > + int local_port;
> > + struct xen_9pfs_data_intf *intf;
> > + unsigned char *data;
> > + struct xen_9pfs_data ring;
> > +
> > + QEMUBH *bh;
> > +
> > + /* local copies, so that we can read/write PDU data directly from
> > + * the ring */
> > + RING_IDX out_cons, out_size, in_cons;
> > + bool inprogress;
> > +};
> > +
>
> QEMU Coding style requires a typedef.
OK
> FWIW, maybe you could also convert
> other structured types like XenDevice or XenDevOps.
I'll do in a separate series
> > typedef struct Xen9pfsDev {
> > struct XenDevice xendev; /* must be first */
> > + V9fsState state;
> > +
> > + int num_rings;
> > + struct Xen9pfsRing *rings;
> > } Xen9pfsDev;
> >
> > static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu,
> > @@ -67,22 +94,152 @@ static int xen_9pfs_init(struct XenDevice *xendev)
> > return 0;
> > }
> >
> > +static void xen_9pfs_bh(void *opaque)
> > +{
> > +}
> > +
> > +static void xen_9pfs_evtchn_event(void *opaque)
> > +{
> > +}
> > +
> > static int xen_9pfs_free(struct XenDevice *xendev)
> > {
> > - return -1;
> > + int i;
> > + struct Xen9pfsDev *xen_9pdev = container_of(xendev, struct Xen9pfsDev,
> > xendev);
> > +
>
> Coding style.
OK
> > + for (i = 0; i < xen_9pdev->num_rings; i++) {
> > + if (xen_9pdev->rings[i].data != NULL) {
> > + xengnttab_unmap(xen_9pdev->xendev.gnttabdev,
> > + xen_9pdev->rings[i].data,
> > + (1 << XEN_9PFS_RING_ORDER));
> > + }
> > + if (xen_9pdev->rings[i].intf != NULL) {
> > + xengnttab_unmap(xen_9pdev->xendev.gnttabdev,
> > + xen_9pdev->rings[i].intf,
> > + 1);
> > + }
> > + if (xen_9pdev->rings[i].evtchndev > 0) {
> > +
> > qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
> > + NULL, NULL, NULL);
> > + xenevtchn_unbind(xen_9pdev->rings[i].evtchndev,
> > xen_9pdev->rings[i].local_port);
> > + }
> > + if (xen_9pdev->rings[i].bh != NULL) {
> > + qemu_bh_delete(xen_9pdev->rings[i].bh);
> > + }
> > + }
> > + g_free(xen_9pdev->rings);
> > + return 0;
> > }
> >
> > static int xen_9pfs_connect(struct XenDevice *xendev)
> > {
> > + int i;
> > + struct Xen9pfsDev *xen_9pdev = container_of(xendev, struct Xen9pfsDev,
> > xendev);
>
> Coding style.
OK
> > + V9fsState *s = &xen_9pdev->state;
> > + QemuOpts *fsdev;
> > + char *security_model, *path;
> > +
> > + if (xenstore_read_fe_int(&xen_9pdev->xendev, "num-rings",
> > + &xen_9pdev->num_rings) == -1 ||
> > + xen_9pdev->num_rings > MAX_RINGS) {
> > + return -1;
> > + }
> > +
> > + xen_9pdev->rings = g_malloc0(xen_9pdev->num_rings * sizeof(struct
> > Xen9pfsRing));
> > + for (i = 0; i < xen_9pdev->num_rings; i++) {
> > + char str[16];
> > +
> > + xen_9pdev->rings[i].priv = xen_9pdev;
> > + xen_9pdev->rings[i].evtchn = -1;
> > + xen_9pdev->rings[i].local_port = -1;
> > +
> > + sprintf(str, "ring-ref%u", i);
> > + if (xenstore_read_fe_int(&xen_9pdev->xendev, str,
> > + &xen_9pdev->rings[i].ref) == -1) {
> > + goto out;
> > + }
> > + sprintf(str, "event-channel-%u", i);
> > + if (xenstore_read_fe_int(&xen_9pdev->xendev, str,
> > + &xen_9pdev->rings[i].evtchn) == -1) {
> > + goto out;
> > + }
> > +
> > + xen_9pdev->rings[i].intf = xengnttab_map_grant_ref(
> > + xen_9pdev->xendev.gnttabdev,
> > + xen_9pdev->xendev.dom,
> > + xen_9pdev->rings[i].ref,
> > + PROT_READ | PROT_WRITE);
> > + if (!xen_9pdev->rings[i].intf) {
> > + goto out;
> > + }
> > + xen_9pdev->rings[i].data = xengnttab_map_domain_grant_refs(
> > + xen_9pdev->xendev.gnttabdev,
> > + (1 << XEN_9PFS_RING_ORDER),
> > + xen_9pdev->xendev.dom,
> > + xen_9pdev->rings[i].intf->ref,
> > + PROT_READ | PROT_WRITE);
> > + if (!xen_9pdev->rings[i].data) {
> > + goto out;
> > + }
> > + xen_9pdev->rings[i].ring.in = xen_9pdev->rings[i].data;
> > + xen_9pdev->rings[i].ring.out = xen_9pdev->rings[i].data +
> > XEN_9PFS_RING_SIZE;
> > +
> > + xen_9pdev->rings[i].bh = qemu_bh_new(xen_9pfs_bh,
> > &xen_9pdev->rings[i]);
> > + xen_9pdev->rings[i].out_cons = 0;
> > + xen_9pdev->rings[i].out_size = 0;
> > + xen_9pdev->rings[i].inprogress = false;
> > +
> > +
> > + xen_9pdev->rings[i].evtchndev = xenevtchn_open(NULL, 0);
> > + if (xen_9pdev->rings[i].evtchndev == NULL) {
> > + goto out;
> > + }
> > + fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), F_SETFD,
> > FD_CLOEXEC);
> > + xen_9pdev->rings[i].local_port = xenevtchn_bind_interdomain
> > + (xen_9pdev->rings[i].evtchndev, xendev->dom,
> > xen_9pdev->rings[i].evtchn);
> > + if (xen_9pdev->rings[i].local_port == -1) {
> > + xen_pv_printf(xendev, 0, "xenevtchn_bind_interdomain failed
> > port=%d\n",
> > + xen_9pdev->rings[i].evtchn);
> > + goto out;
> > + }
> > + xen_pv_printf(xendev, 2, "bind evtchn port %d\n",
> > xendev->local_port);
> > + qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
> > + xen_9pfs_evtchn_event, NULL, &xen_9pdev->rings[i]);
> > + }
> > +
> > + security_model = xenstore_read_be_str(xendev, "security_model");
> > + path = xenstore_read_be_str(xendev, "path");
> > + s->fsconf.fsdev_id = g_malloc(strlen("xen9p") + 6);
> > + sprintf(s->fsconf.fsdev_id, "xen9p%d", xendev->dev);
>
> Please use g_strdup_printf().
I'll do
> > + s->fsconf.tag = xenstore_read_fe_str(xendev, "tag");
> > + v9fs_register_transport(s, &xen_9p_transport);
> > + fsdev = qemu_opts_create(qemu_find_opts("fsdev"),
> > + s->fsconf.tag,
> > + 1, NULL);
> > + qemu_opt_set(fsdev, "fsdriver", "local", NULL);
> > + qemu_opt_set(fsdev, "path", path, NULL);
> > + qemu_opt_set(fsdev, "security_model", security_model, NULL);
> > + qemu_opts_set_id(fsdev, s->fsconf.fsdev_id);
> > + qemu_fsdev_add(fsdev);
> > + v9fs_device_realize_common(s, NULL);
> > +
> > return 0;
> > +
> > +out:
> > + xen_9pfs_free(xendev);
> > + return -1;
> > }
> >
> > static void xen_9pfs_alloc(struct XenDevice *xendev)
> > {
> > + xenstore_write_be_str(xendev, "versions", VERSIONS);
> > + xenstore_write_be_int(xendev, "max-rings", MAX_RINGS);
> > + xenstore_write_be_int(xendev, "max-ring-page-order", MAX_RING_ORDER);
> > }
> >
> > static void xen_9pfs_disconnect(struct XenDevice *xendev)
> > {
> > + /* Dynamic hotplug of PV filesystems at runtime is not supported. */
>
> Does this mean that this function is never called ? Or that it should
> report an error ? Or print one ?
This function is called, but only at shutdown.
> In any case, it looks weird that it doesn't free the fsdev_id that
> was allocated in xen_9pfs_connect().
I'll free it in xen_9pfs_free
> > }
> >
> > struct XenDevOps xen_9pfs_ops = {
>
>
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