On 15.02.24 14:04, Juergen Gross wrote:
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 <[email protected]> Reviewed-by: Jason Andryuk <[email protected]> Acked-by: Anthony PERARD <[email protected]>
Seems CI is unhappy due to a false positive.
The following diff needs to be folded in:
diff --git a/tools/9pfsd/io.c b/tools/9pfsd/io.c
index 4312a62dfe..996017a8be 100644
--- a/tools/9pfsd/io.c
+++ b/tools/9pfsd/io.c
@@ -104,7 +104,7 @@ void *io_thread(void *arg)
{
struct ring *ring = arg;
unsigned int count = 0;
- struct p9_header hdr;
+ struct p9_header hdr = { .size = 0 };
bool in_hdr = true;
ring->max_size = ring->ring_size;
Juergen
--- V2: - rename put_request_bytes() (Jason Andryuk) - rename get_request_bytes() and put_response_bytes() len parameter (Jason Andryuk) - don't unmask event channel if error indicator is set (Jason Andryuk) --- 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..4312a62dfe 100644 --- a/tools/9pfsd/io.c +++ b/tools/9pfsd/io.c @@ -6,39 +6,176 @@ * Copyright (C) 2024 Juergen Gross <[email protected]> * * 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; + 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 {
OpenPGP_0xB0DE9DD628BF132F.asc
Description: OpenPGP public key
OpenPGP_signature.asc
Description: OpenPGP digital signature
