| Message ID | 20240215130509.24008-4-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tools: enable xenstore-stubdom to use 9pfs | expand |
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 <jgross@suse.com> > Reviewed-by: Jason Andryuk <jandryuk@gmail.com> > Acked-by: Anthony PERARD <anthony.perard@citrix.com> 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 <jgross@suse.com> > * > * 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 {
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 <jgross@suse.com> * * 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 {