[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] tools/xen-9pfsd: add transport layer
commit 8219809423a6c2164e4f036ae418087a39f40dd1 Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Thu Feb 15 14:04:51 2024 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Thu Feb 15 16:24:39 2024 +0000 tools/xen-9pfsd: add transport layer Add the transport layer of 9pfs. This is basically the infrastructure to receive requests from the frontend and to send the related answers via the rings. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx> Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx> --- tools/9pfsd/io.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++- tools/9pfsd/xen-9pfsd.h | 16 ++++++ 2 files changed, 156 insertions(+), 3 deletions(-) diff --git a/tools/9pfsd/io.c b/tools/9pfsd/io.c index eb7c136e09..996017a8be 100644 --- a/tools/9pfsd/io.c +++ b/tools/9pfsd/io.c @@ -6,39 +6,176 @@ * Copyright (C) 2024 Juergen Gross <jgross@xxxxxxxx> * * I/O thread handling. + * + * Only handle one request at a time, pushing out the complete response + * before looking for the next request. */ #include <stdbool.h> +#include <stdlib.h> #include <string.h> #include <syslog.h> +#include <xenctrl.h> /* For cpu barriers. */ +#include <xen-tools/common-macros.h> #include "xen-9pfsd.h" +/* + * Note that the ring names "in" and "out" are from the frontend's + * perspective, so the "in" ring will be used for responses to the frontend, + * while the "out" ring is used for requests from the frontend to the + * backend. + */ +static unsigned int ring_in_free(struct ring *ring) +{ + unsigned int queued; + + queued = xen_9pfs_queued(ring->prod_pvt_in, ring->intf->in_cons, + ring->ring_size); + xen_rmb(); + + return ring->ring_size - queued; +} + +static unsigned int ring_out_data(struct ring *ring) +{ + unsigned int queued; + + queued = xen_9pfs_queued(ring->intf->out_prod, ring->cons_pvt_out, + ring->ring_size); + xen_rmb(); + + return queued; +} + +static unsigned int get_request_bytes(struct ring *ring, unsigned int off, + unsigned int total_len) +{ + unsigned int size; + unsigned int out_data = ring_out_data(ring); + RING_IDX prod, cons; + + size = min(total_len - off, out_data); + prod = xen_9pfs_mask(ring->intf->out_prod, ring->ring_size); + cons = xen_9pfs_mask(ring->cons_pvt_out, ring->ring_size); + xen_9pfs_read_packet(ring->buffer + off, ring->data.out, size, + prod, &cons, ring->ring_size); + + xen_rmb(); /* Read data out before setting visible consumer. */ + ring->cons_pvt_out += size; + ring->intf->out_cons = ring->cons_pvt_out; + + /* Signal that more space is available now. */ + xenevtchn_notify(xe, ring->evtchn); + + return size; +} + +static unsigned int put_response_bytes(struct ring *ring, unsigned int off, + unsigned int total_len) +{ + unsigned int size; + unsigned int in_data = ring_in_free(ring); + RING_IDX prod, cons; + + size = min(total_len - off, in_data); + prod = xen_9pfs_mask(ring->prod_pvt_in, ring->ring_size); + cons = xen_9pfs_mask(ring->intf->in_cons, ring->ring_size); + xen_9pfs_write_packet(ring->data.in, ring->buffer + off, size, + &prod, cons, ring->ring_size); + + xen_wmb(); /* Write data out before setting visible producer. */ + ring->prod_pvt_in += size; + ring->intf->in_prod = ring->prod_pvt_in; + + return size; +} + static bool io_work_pending(struct ring *ring) { if ( ring->stop_thread ) return true; - return false; + if ( ring->error ) + return false; + return ring->handle_response ? ring_in_free(ring) : ring_out_data(ring); } void *io_thread(void *arg) { struct ring *ring = arg; + unsigned int count = 0; + struct p9_header hdr = { .size = 0 }; + bool in_hdr = true; + + ring->max_size = ring->ring_size; + ring->buffer = malloc(ring->max_size); + if ( !ring->buffer ) + { + syslog(LOG_CRIT, "memory allocation failure!"); + return NULL; + } while ( !ring->stop_thread ) { pthread_mutex_lock(&ring->mutex); if ( !io_work_pending(ring) ) { - if ( xenevtchn_unmask(xe, ring->evtchn) < 0 ) + if ( !ring->error && xenevtchn_unmask(xe, ring->evtchn) < 0 ) syslog(LOG_WARNING, "xenevtchn_unmask() failed"); pthread_cond_wait(&ring->cond, &ring->mutex); } pthread_mutex_unlock(&ring->mutex); - /* TODO: I/O handling. */ + if ( ring->stop_thread || ring->error ) + continue; + + if ( !ring->handle_response ) + { + if ( in_hdr ) + { + count += get_request_bytes(ring, count, sizeof(hdr)); + if ( count != sizeof(hdr) ) + continue; + hdr = *(struct p9_header *)ring->buffer; + if ( hdr.size > ring->max_size || hdr.size < sizeof(hdr) ) + { + syslog(LOG_ERR, "%u.%u specified illegal request length %u", + ring->device->domid, ring->device->devid, hdr.size); + ring->error = true; + continue; + } + in_hdr = false; + } + + count += get_request_bytes(ring, count, hdr.size); + if ( count < hdr.size ) + continue; + + /* TODO: handle request (will rewrite hdr.size). */ + + ring->handle_response = true; + hdr.size = ((struct p9_header *)ring->buffer)->size; + count = 0; + } + + if ( ring->handle_response ) + { + count += put_response_bytes(ring, count, hdr.size); + + if ( count == hdr.size ) + { + /* Signal presence of response. */ + xenevtchn_notify(xe, ring->evtchn); + + ring->handle_response = false; + in_hdr = true; + count = 0; + } + } } + free(ring->buffer); + ring->thread_active = false; return NULL; diff --git a/tools/9pfsd/xen-9pfsd.h b/tools/9pfsd/xen-9pfsd.h index ff3562164a..d587f59a32 100644 --- a/tools/9pfsd/xen-9pfsd.h +++ b/tools/9pfsd/xen-9pfsd.h @@ -15,6 +15,12 @@ #define MAX_RING_ORDER 9 #define MAX_OPEN_FILES_DEFAULT 5 +struct p9_header { + uint32_t size; + uint8_t cmd; + uint16_t tag; +} __attribute__((packed)); + typedef struct device device; struct ring { @@ -29,7 +35,17 @@ struct ring { struct xen_9pfs_data_intf *intf; unsigned int ring_order; RING_IDX ring_size; + + /* Transport layer data. */ struct xen_9pfs_data data; + RING_IDX prod_pvt_in; + RING_IDX cons_pvt_out; + + /* Request and response handling. */ + uint32_t max_size; + bool error; /* Protocol error - stop processing. */ + bool handle_response; /* Main loop now handling response. */ + void *buffer; /* Request/response buffer. */ }; struct device { -- generated by git-patchbot for /home/xen/git/xen.git#master
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