diff options
Diffstat (limited to 'tools/ocaml/libs/xb/xs_ring_stubs.c')
-rw-r--r-- | tools/ocaml/libs/xb/xs_ring_stubs.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/tools/ocaml/libs/xb/xs_ring_stubs.c b/tools/ocaml/libs/xb/xs_ring_stubs.c index 00414c5353..4888ac5631 100644 --- a/tools/ocaml/libs/xb/xs_ring_stubs.c +++ b/tools/ocaml/libs/xb/xs_ring_stubs.c @@ -39,21 +39,23 @@ static int xs_ring_read(struct mmap_interface *interface, char *buffer, int len) { struct xenstore_domain_interface *intf = interface->addr; - XENSTORE_RING_IDX cons, prod; + XENSTORE_RING_IDX cons, prod; /* offsets only */ int to_read; - cons = intf->req_cons; - prod = intf->req_prod; + cons = *(volatile uint32*)&intf->req_cons; + prod = *(volatile uint32*)&intf->req_prod; xen_mb(); + cons = MASK_XENSTORE_IDX(cons); + prod = MASK_XENSTORE_IDX(prod); if (prod == cons) return 0; - if (MASK_XENSTORE_IDX(prod) > MASK_XENSTORE_IDX(cons)) + if (prod > cons) to_read = prod - cons; else - to_read = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons); + to_read = XENSTORE_RING_SIZE - cons; if (to_read < len) len = to_read; - memcpy(buffer, intf->req + MASK_XENSTORE_IDX(cons), len); + memcpy(buffer, intf->req + cons, len); xen_mb(); intf->req_cons += len; return len; @@ -66,8 +68,8 @@ static int xs_ring_write(struct mmap_interface *interface, XENSTORE_RING_IDX cons, prod; int can_write; - cons = intf->rsp_cons; - prod = intf->rsp_prod; + cons = *(volatile uint32*)&intf->rsp_cons; + prod = *(volatile uint32*)&intf->rsp_prod; xen_mb(); if ( (prod - cons) >= XENSTORE_RING_SIZE ) return 0; |