Support complex backend/frontend hierarchies #7
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`service_vm_va` is a bit redundant here -- `vaddr` should be enough. Signed-off-by: Hannu Lyytinen <[email protected]>
Signed-off-by: Hannu Lyytinen <[email protected]>
Signed-off-by: Hannu Lyytinen <[email protected]>
Despite eliminating all locks on ring buffers, userspace helper (such as QEMU) can access the buffers without context switches to kernel. Signed-off-by: Hannu Lyytinen <[email protected]>
Signed-off-by: Hannu Lyytinen <[email protected]>
Userspace helper (such as QEMU) is now able to ring the doorbell without context switch to kernel. Signed-off-by: Hannu Lyytinen <[email protected]>
elmankku
requested changes
Oct 25, 2023
| #define RPC_MR0_STATE_SHIFT (RPC_MR0_OP_WIDTH + RPC_MR0_OP_SHIFT) | ||
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| #define RPC_MR0_STATE_COMPLETE 0 | ||
| #define RPC_MR0_STATE_RESERVED 1 |
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Reserved here means unused...?
| static inline | ||
| sel4_rpc_t *rpcmsg_commit(sel4_rpc_t *rpc, rpcmsg_t *msg) | ||
| { | ||
| msg->mr0 = BIT_FIELD_SET(msg->mr0, RPC_MR0_STATE, RPC_MR0_STATE_PENDING); |
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Write release / write barrier
| rpcmsg_t *rpcmsg_queue_advance_tail(rpcmsg_queue_t *q) | ||
| { | ||
| rpc_assert((!rpcmsg_queue_full(q))); | ||
| q->tail = QUEUE_NEXT(q->tail); |
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This should have write release / write barrier
| rpcmsg_t *rpcmsg_queue_advance_head(rpcmsg_queue_t *q) | ||
| { | ||
| rpc_assert(!rpcmsg_queue_empty(q)); | ||
| q->head = QUEUE_NEXT(q->head); |
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This should have write release / write barrier
| rpc_assert(!"tx queue full"); | ||
| } | ||
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| switch (BIT_FIELD_GET(msg->mr0, RPC_MR0_STATE)) { |
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Load acquire / read barrier
| return NULL; | ||
| } | ||
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| next = QUEUE_NEXT(msg - q->data); |
| ((uint32_t *) dataport->mem[0].service_vm_va)[0] = 1; | ||
| uint32_t *emit_register = private; | ||
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| *emit_register = 1; |
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I think write barrier here to ensure ordering of writes
| smp_store_release(&ioreq->state, | ||
| SEL4_IOREQ_STATE_PROCESSING); | ||
| set_bit(slot, vm->ioreq_map); | ||
| req->mr0 = BIT_FIELD_SET(req->mr0, RPC_MR0_STATE, RPC_MR0_STATE_PROCESSING); |
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Store release to ensure others share the view
| rpc = driver_ack_mmio_finish(rpc, slot, 0); | ||
| BUG_ON(!rpc); | ||
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| req->mr0 = BIT_FIELD_SET(req->mr0, RPC_MR0_STATE, RPC_MR0_STATE_COMPLETE); |
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Store release to ensure order of writes
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