diff options
Diffstat (limited to 'hw/9pfs/xen-9p-backend.c')
| -rw-r--r-- | hw/9pfs/xen-9p-backend.c | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c new file mode 100644 index 0000000000..9c7f41af99 --- /dev/null +++ b/hw/9pfs/xen-9p-backend.c @@ -0,0 +1,440 @@ +/* + * Xen 9p backend + * + * Copyright Aporeto 2017 + * + * Authors: + * Stefano Stabellini <stefano@aporeto.com> + * + */ + +#include "qemu/osdep.h" + +#include "hw/hw.h" +#include "hw/9pfs/9p.h" +#include "hw/xen/xen_backend.h" +#include "hw/9pfs/xen-9pfs.h" +#include "qemu/config-file.h" +#include "fsdev/qemu-fsdev.h" + +#define VERSIONS "1" +#define MAX_RINGS 8 +#define MAX_RING_ORDER 8 + +typedef struct Xen9pfsRing { + struct Xen9pfsDev *priv; + + int ref; + xenevtchn_handle *evtchndev; + int evtchn; + int local_port; + int ring_order; + struct xen_9pfs_data_intf *intf; + unsigned char *data; + struct xen_9pfs_data ring; + + struct iovec *sg; + 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; +} Xen9pfsRing; + +typedef struct Xen9pfsDev { + struct XenDevice xendev; /* must be first */ + V9fsState state; + char *path; + char *security_model; + char *tag; + char *id; + + int num_rings; + Xen9pfsRing *rings; +} Xen9pfsDev; + +static void xen_9pfs_in_sg(Xen9pfsRing *ring, + struct iovec *in_sg, + int *num, + uint32_t idx, + uint32_t size) +{ + RING_IDX cons, prod, masked_prod, masked_cons; + + cons = ring->intf->in_cons; + prod = ring->intf->in_prod; + xen_rmb(); + masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order)); + masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order)); + + if (masked_prod < masked_cons) { + in_sg[0].iov_base = ring->ring.in + masked_prod; + in_sg[0].iov_len = masked_cons - masked_prod; + *num = 1; + } else { + in_sg[0].iov_base = ring->ring.in + masked_prod; + in_sg[0].iov_len = XEN_FLEX_RING_SIZE(ring->ring_order) - masked_prod; + in_sg[1].iov_base = ring->ring.in; + in_sg[1].iov_len = masked_cons; + *num = 2; + } +} + +static void xen_9pfs_out_sg(Xen9pfsRing *ring, + struct iovec *out_sg, + int *num, + uint32_t idx) +{ + RING_IDX cons, prod, masked_prod, masked_cons; + + cons = ring->intf->out_cons; + prod = ring->intf->out_prod; + xen_rmb(); + masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order)); + masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order)); + + if (masked_cons < masked_prod) { + out_sg[0].iov_base = ring->ring.out + masked_cons; + out_sg[0].iov_len = ring->out_size; + *num = 1; + } else { + if (ring->out_size > + (XEN_FLEX_RING_SIZE(ring->ring_order) - masked_cons)) { + out_sg[0].iov_base = ring->ring.out + masked_cons; + out_sg[0].iov_len = XEN_FLEX_RING_SIZE(ring->ring_order) - + masked_cons; + out_sg[1].iov_base = ring->ring.out; + out_sg[1].iov_len = ring->out_size - + (XEN_FLEX_RING_SIZE(ring->ring_order) - + masked_cons); + *num = 2; + } else { + out_sg[0].iov_base = ring->ring.out + masked_cons; + out_sg[0].iov_len = ring->out_size; + *num = 1; + } + } +} + +static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu, + size_t offset, + const char *fmt, + va_list ap) +{ + Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); + struct iovec in_sg[2]; + int num; + + xen_9pfs_in_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings], + in_sg, &num, pdu->idx, ROUND_UP(offset + 128, 512)); + return v9fs_iov_vmarshal(in_sg, num, offset, 0, fmt, ap); +} + +static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu, + size_t offset, + const char *fmt, + va_list ap) +{ + Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); + struct iovec out_sg[2]; + int num; + + xen_9pfs_out_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings], + out_sg, &num, pdu->idx); + return v9fs_iov_vunmarshal(out_sg, num, offset, 0, fmt, ap); +} + +static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu, + struct iovec **piov, + unsigned int *pniov) +{ + Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); + Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings]; + int num; + + g_free(ring->sg); + + ring->sg = g_malloc0(sizeof(*ring->sg) * 2); + xen_9pfs_out_sg(ring, ring->sg, &num, pdu->idx); + *piov = ring->sg; + *pniov = num; +} + +static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu, + struct iovec **piov, + unsigned int *pniov, + size_t size) +{ + Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); + Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings]; + int num; + + g_free(ring->sg); + + ring->sg = g_malloc0(sizeof(*ring->sg) * 2); + xen_9pfs_in_sg(ring, ring->sg, &num, pdu->idx, size); + *piov = ring->sg; + *pniov = num; +} + +static void xen_9pfs_push_and_notify(V9fsPDU *pdu) +{ + RING_IDX prod; + Xen9pfsDev *priv = container_of(pdu->s, Xen9pfsDev, state); + Xen9pfsRing *ring = &priv->rings[pdu->tag % priv->num_rings]; + + g_free(ring->sg); + ring->sg = NULL; + + ring->intf->out_cons = ring->out_cons; + xen_wmb(); + + prod = ring->intf->in_prod; + xen_rmb(); + ring->intf->in_prod = prod + pdu->size; + xen_wmb(); + + ring->inprogress = false; + xenevtchn_notify(ring->evtchndev, ring->local_port); + + qemu_bh_schedule(ring->bh); +} + +static const struct V9fsTransport xen_9p_transport = { + .pdu_vmarshal = xen_9pfs_pdu_vmarshal, + .pdu_vunmarshal = xen_9pfs_pdu_vunmarshal, + .init_in_iov_from_pdu = xen_9pfs_init_in_iov_from_pdu, + .init_out_iov_from_pdu = xen_9pfs_init_out_iov_from_pdu, + .push_and_notify = xen_9pfs_push_and_notify, +}; + +static int xen_9pfs_init(struct XenDevice *xendev) +{ + return 0; +} + +static int xen_9pfs_receive(Xen9pfsRing *ring) +{ + P9MsgHeader h; + RING_IDX cons, prod, masked_prod, masked_cons; + V9fsPDU *pdu; + + if (ring->inprogress) { + return 0; + } + + cons = ring->intf->out_cons; + prod = ring->intf->out_prod; + xen_rmb(); + + if (xen_9pfs_queued(prod, cons, XEN_FLEX_RING_SIZE(ring->ring_order)) < + sizeof(h)) { + return 0; + } + ring->inprogress = true; + + masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order)); + masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order)); + + xen_9pfs_read_packet((uint8_t *) &h, ring->ring.out, sizeof(h), + masked_prod, &masked_cons, + XEN_FLEX_RING_SIZE(ring->ring_order)); + + /* cannot fail, because we only handle one request per ring at a time */ + pdu = pdu_alloc(&ring->priv->state); + pdu->size = le32_to_cpu(h.size_le); + pdu->id = h.id; + pdu->tag = le32_to_cpu(h.tag_le); + ring->out_size = le32_to_cpu(h.size_le); + ring->out_cons = cons + le32_to_cpu(h.size_le); + + qemu_co_queue_init(&pdu->complete); + pdu_submit(pdu); + + return 0; +} + +static void xen_9pfs_bh(void *opaque) +{ + Xen9pfsRing *ring = opaque; + xen_9pfs_receive(ring); +} + +static void xen_9pfs_evtchn_event(void *opaque) +{ + Xen9pfsRing *ring = opaque; + evtchn_port_t port; + + port = xenevtchn_pending(ring->evtchndev); + xenevtchn_unmask(ring->evtchndev, port); + + qemu_bh_schedule(ring->bh); +} + +static int xen_9pfs_free(struct XenDevice *xendev) +{ + int i; + Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev); + + g_free(xen_9pdev->id); + g_free(xen_9pdev->tag); + g_free(xen_9pdev->path); + g_free(xen_9pdev->security_model); + + 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_9pdev->rings[i].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; + Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev); + V9fsState *s = &xen_9pdev->state; + QemuOpts *fsdev; + + if (xenstore_read_fe_int(&xen_9pdev->xendev, "num-rings", + &xen_9pdev->num_rings) == -1 || + xen_9pdev->num_rings > MAX_RINGS || xen_9pdev->num_rings < 1) { + return -1; + } + + xen_9pdev->rings = g_malloc0(xen_9pdev->num_rings * sizeof(Xen9pfsRing)); + for (i = 0; i < xen_9pdev->num_rings; i++) { + char *str; + int ring_order; + + xen_9pdev->rings[i].priv = xen_9pdev; + xen_9pdev->rings[i].evtchn = -1; + xen_9pdev->rings[i].local_port = -1; + + str = g_strdup_printf("ring-ref%u", i); + if (xenstore_read_fe_int(&xen_9pdev->xendev, str, + &xen_9pdev->rings[i].ref) == -1) { + goto out; + } + g_free(str); + str = g_strdup_printf("event-channel-%u", i); + if (xenstore_read_fe_int(&xen_9pdev->xendev, str, + &xen_9pdev->rings[i].evtchn) == -1) { + goto out; + } + g_free(str); + + 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; + } + ring_order = xen_9pdev->rings[i].intf->ring_order; + if (ring_order > MAX_RING_ORDER) { + goto out; + } + xen_9pdev->rings[i].ring_order = ring_order; + xen_9pdev->rings[i].data = xengnttab_map_domain_grant_refs( + xen_9pdev->xendev.gnttabdev, + (1 << 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_FLEX_RING_SIZE(ring_order); + + 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]); + } + + xen_9pdev->security_model = xenstore_read_be_str(xendev, "security_model"); + xen_9pdev->path = xenstore_read_be_str(xendev, "path"); + xen_9pdev->id = s->fsconf.fsdev_id = + g_strdup_printf("xen9p%d", xendev->dev); + xen_9pdev->tag = 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", xen_9pdev->path, NULL); + qemu_opt_set(fsdev, "security_model", xen_9pdev->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. */ +} + +struct XenDevOps xen_9pfs_ops = { + .size = sizeof(Xen9pfsDev), + .flags = DEVOPS_FLAG_NEED_GNTDEV, + .alloc = xen_9pfs_alloc, + .init = xen_9pfs_init, + .initialise = xen_9pfs_connect, + .disconnect = xen_9pfs_disconnect, + .free = xen_9pfs_free, +}; |