Commit 5f4e42b8 authored by Nikos Dragazis's avatar Nikos Dragazis Committed by Jim Harris
Browse files

vhost: abstract vring call mechanism as it is transport-specific 



vring notification mechanism is transport-specific.  At present, vhost
dataplane code in `lib/vhost/vhost.c` triggers guest notifications with
`eventfd_write()` system call. But this is an AF_UNIX specific
notification mechanism. This patch replaces `eventfd_write()` with the
existing generic `rte_vhost_vring_call()` function that is part of
DPDK's librte_vhost public API.

`rte_vhost_vring_call()` takes a vring_idx as an argument to associate
the `struct spdk_vhost_virtqueue` instance with the relevant `struct
vhost_virtqueue` instance. We introduce a new `vring_idx` field in
`struct spdk_vhost_virtqueue` to enable this association. This field is
initialized in `start_device()`. In addition, a stub for
`rte_vhost_vring_call()` is added in the vhost unit test file.

SPDK's internal `rte_vhost` copy will not be updated in order to support
the virtio-vhost-user transport. However, an `rte_vhost_vring_call()`
function is introduced in SPDK's `rte_vhost` in order to have a solid
API. This function is just a wrapper of `eventfd_write()`.

Change-Id: Ic93e25cd3f06e92f04766521bc850f1ee80b8ec8
Signed-off-by: default avatarNikos Dragazis <ndragazis@arrikto.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/454373


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarDarek Stojaczyk <dariusz.stojaczyk@intel.com>
parent 0bfc6143

lib/vhost/rte_vhost/rte_vhost.h

+12 −0
Original line number Diff line number Diff line
@@ -472,4 +472,16 @@ int rte_vhost_set_vring_base(int vid, uint16_t queue_id, 
int rte_vhost_get_vring_base(int vid, uint16_t queue_id,

		uint16_t *last_avail_idx, uint16_t *last_used_idx);



/**

 * Notify the guest that used descriptors have been added to the vring.

 *

 * @param vid

 *  vhost device ID

 * @param vring_idx

 *  vring index

 * @return

 *  0 on success, -1 on failure

 */

int rte_vhost_vring_call(int vid, uint16_t vring_idx);



#endif /* _RTE_VHOST_H_ */

lib/vhost/rte_vhost/vhost.c

+25 −0
Original line number Diff line number Diff line
@@ -503,3 +503,28 @@ rte_vhost_get_vring_base(int vid, uint16_t vring_idx, 


	return 0;

}



int

rte_vhost_vring_call(int vid, uint16_t vring_idx)

{

	struct virtio_net *dev;

	struct vhost_virtqueue *vq;



	dev = get_device(vid);

	if(!dev)

		return -1;



	if (vring_idx >= VHOST_MAX_VRING)

		return -1;



	vq = dev->virtqueue[vring_idx];

	if (!vq)

		return -1;



	if (vq->callfd != -1) {

		eventfd_write(vq->callfd, (eventfd_t)1);

		return 0;

	}



	return -1;

}

lib/vhost/vhost.c

+10 −5
Original line number Diff line number Diff line
@@ -278,8 +278,13 @@ spdk_vhost_vq_used_signal(struct spdk_vhost_session *vsession, 
		      "Queue %td - USED RING: sending IRQ: last used %"PRIu16"\n",

		      virtqueue - vsession->virtqueue, virtqueue->last_used_idx);



	eventfd_write(virtqueue->vring.callfd, (eventfd_t)1);

	if (rte_vhost_vring_call(vsession->vid, virtqueue->vring_idx) == 0) {

		/* interrupt signalled */

		return 1;

	} else {

		/* interrupt not signalled */

		return 0;

	}

}
@@ -1118,9 +1123,11 @@ start_device(int vid) 
	for (i = 0; i < SPDK_VHOST_MAX_VQUEUES; i++) {

		struct spdk_vhost_virtqueue *q = &vsession->virtqueue[i];



		q->vring_idx = -1;

		if (rte_vhost_get_vhost_vring(vid, i, &q->vring)) {

			continue;

		}

		q->vring_idx = i;



		if (q->vring.desc == NULL || q->vring.size == 0) {

			continue;
@@ -1160,9 +1167,7 @@ start_device(int vid) 
	 * Tested on QEMU 2.10.91 and 2.11.50.

	 */

	for (i = 0; i < vsession->max_queues; i++) {

		if (vsession->virtqueue[i].vring.callfd != -1) {

			eventfd_write(vsession->virtqueue[i].vring.callfd, (eventfd_t)1);

		}

		rte_vhost_vring_call(vsession->vid, vsession->virtqueue[i].vring_idx);

	}



	spdk_vhost_session_set_coalescing(vdev, vsession, NULL);

lib/vhost/vhost_internal.h

+2 −0
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ struct spdk_vhost_virtqueue { 
	/* Next time when we need to send event */

	uint64_t next_event_time;



	/* Associated vhost_virtqueue in the virtio device's virtqueue list */

	uint32_t vring_idx;

} __attribute((aligned(SPDK_CACHE_LINE_SIZE)));



struct spdk_vhost_session {

test/unit/lib/vhost/vhost.c/vhost_ut.c

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ DEFINE_STUB(spdk_event_allocate, struct spdk_event *, 
	    (uint32_t lcore, spdk_event_fn fn, void *arg1, void *arg2), NULL);

DEFINE_STUB(spdk_mem_register, int, (void *vaddr, size_t len), 0);

DEFINE_STUB(spdk_mem_unregister, int, (void *vaddr, size_t len), 0);

DEFINE_STUB(rte_vhost_vring_call, int, (int vid, uint16_t vring_idx), 0);



static struct spdk_cpuset *g_app_core_mask;

struct spdk_cpuset *spdk_app_get_core_mask(void)