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Qfix mmio #95

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merged 2 commits into from
Dec 12, 2017
Merged

Qfix mmio #95

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679c8cb
fix for an mmio race condition when multiple threads address the mmio…
LanceThompson Dec 5, 2017
362d44c
release lock a little later in mmio read routines
LanceThompson Dec 12, 2017
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44 changes: 44 additions & 0 deletions libcxl/libcxl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -890,6 +890,7 @@ static struct cxl_afu_h *_new_afu(uint16_t afu_map, uint16_t position, int fd)
return NULL;

pthread_mutex_init(&(afu->event_lock), NULL);
pthread_mutex_init(&(afu->mmio_lock), NULL);
afu->fd = fd;
afu->map = afu_map;
afu->dbg_id = (major << 4) | minor;
Expand Down Expand Up @@ -942,6 +943,7 @@ static void _release_afus(struct cxl_afu_h *afu)
if (afu->id)
free(afu->id);
pthread_mutex_destroy(&(afu->event_lock));
pthread_mutex_destroy(&(afu->mmio_lock));
free(afu);
}
}
Expand Down Expand Up @@ -1029,6 +1031,7 @@ static struct cxl_afu_h *_pslse_open(int *fd, uint16_t afu_map, uint8_t major,

open_fail:
pthread_mutex_destroy(&(afu->event_lock));
pthread_mutex_destroy(&(afu->mmio_lock));
free(afu);
errno = ENODEV;
return NULL;
Expand Down Expand Up @@ -1349,6 +1352,7 @@ void cxl_afu_free(struct cxl_afu_h *afu)
free(afu->id);
free_done_no_afu:
pthread_mutex_destroy(&(afu->event_lock));
pthread_mutex_destroy(&(afu->mmio_lock));
free(afu);
}

Expand Down Expand Up @@ -1585,11 +1589,21 @@ int cxl_mmio_write64(struct cxl_afu_h *afu, uint64_t offset, uint64_t data)
if ((afu == NULL) || !afu->mapped)
goto write64_fail;

// obtain mmio lock before reading and updating mmio structure
while (1) {
pthread_mutex_lock( &(afu->mmio_lock) );
if ( afu->mmio.state == LIBCXL_REQ_IDLE ) break; // it is ok to make the mmio request
pthread_mutex_unlock( &(afu->mmio_lock) );
_delay_1ms();
}

// Send MMIO map to PSLSE
afu->mmio.type = PSLSE_MMIO_WRITE64;
afu->mmio.addr = (uint32_t) offset;
afu->mmio.data = data;
afu->mmio.state = LIBCXL_REQ_REQUEST;
pthread_mutex_unlock( &(afu->mmio_lock) );

while (afu->mmio.state != LIBCXL_REQ_IDLE) /*infinite loop */
_delay_1ms();

Expand All @@ -1612,13 +1626,23 @@ int cxl_mmio_read64(struct cxl_afu_h *afu, uint64_t offset, uint64_t * data)
if ((afu == NULL) || !afu->mapped)
goto read64_fail;

// obtain mmio lock before reading and updating mmio structure
while (1) {
pthread_mutex_lock( &(afu->mmio_lock) );
if ( afu->mmio.state == LIBCXL_REQ_IDLE ) break; // it is ok to make the mmio request
pthread_mutex_unlock( &(afu->mmio_lock) );
_delay_1ms();
}

// Send MMIO map to PSLSE
afu->mmio.type = PSLSE_MMIO_READ64;
afu->mmio.addr = (uint32_t) offset;
afu->mmio.state = LIBCXL_REQ_REQUEST;

while (afu->mmio.state != LIBCXL_REQ_IDLE) /*infinite loop */
_delay_1ms();
*data = afu->mmio.data;
pthread_mutex_unlock( &(afu->mmio_lock) );

if (!afu->opened)
goto read64_fail;
Expand Down Expand Up @@ -1716,11 +1740,21 @@ int cxl_mmio_write32(struct cxl_afu_h *afu, uint64_t offset, uint32_t data)
if ((afu == NULL) || !afu->mapped)
goto write32_fail;

// obtain mmio lock before reading and updating mmio structure
while (1) {
pthread_mutex_lock( &(afu->mmio_lock) );
if ( afu->mmio.state == LIBCXL_REQ_IDLE ) break; // it is ok to make the mmio request
pthread_mutex_unlock( &(afu->mmio_lock) );
_delay_1ms();
}

// Send MMIO map to PSLSE
afu->mmio.type = PSLSE_MMIO_WRITE32;
afu->mmio.addr = (uint32_t) offset;
afu->mmio.data = (uint64_t) data;
afu->mmio.state = LIBCXL_REQ_REQUEST;
pthread_mutex_unlock( &(afu->mmio_lock) );

while (afu->mmio.state != LIBCXL_REQ_IDLE) /*infinite loop */
_delay_1ms();

Expand All @@ -1743,13 +1777,23 @@ int cxl_mmio_read32(struct cxl_afu_h *afu, uint64_t offset, uint32_t * data)
if ((afu == NULL) || !afu->mapped)
goto read32_fail;

// obtain mmio lock before reading and updating mmio structure
while (1) {
pthread_mutex_lock( &(afu->mmio_lock) );
if ( afu->mmio.state == LIBCXL_REQ_IDLE ) break; // it is ok to make the mmio request
pthread_mutex_unlock( &(afu->mmio_lock) );
_delay_1ms();
}

// Send MMIO map to PSLSE
afu->mmio.type = PSLSE_MMIO_READ32;
afu->mmio.addr = (uint32_t) offset;
afu->mmio.state = LIBCXL_REQ_REQUEST;

while (afu->mmio.state != LIBCXL_REQ_IDLE) /*infinite loop */
_delay_1ms();
*data = (uint32_t) afu->mmio.data;
pthread_mutex_unlock( &(afu->mmio_lock) );

if (!afu->opened)
goto read32_fail;
Expand Down
1 change: 1 addition & 0 deletions libcxl/libcxl_internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ struct mmio_req {
struct cxl_afu_h {
pthread_t thread;
pthread_mutex_t event_lock;
pthread_mutex_t mmio_lock;
struct cxl_event **events;
int adapter;
char *id;
Expand Down