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authorSteven Luong <sluong@cisco.com>2020-11-17 13:30:44 -0800
committerBeno�t Ganne <bganne@cisco.com>2021-01-08 13:10:58 +0000
commit27ba5008a16eddccc0b285272de7f89fd0aa3a24 (patch)
tree3065040b62ee15ac45b1c1d77dd7421dcb558a5d /src/vnet/devices/virtio/vhost_user_inline.h
parented4b38e868c7cabb8e88cc0f1254c95a8f1c5939 (diff)
vhost: Add event index for interrupt notification to driver
VPP only supports a poor man's approach for interrupt notification to the driver. It uses a simple binary flag for "interrupt needed" or "interrupt not needed". Most drivers support more sophisticated event index already. This feature is to add the long due missing feature and make it configurable, off by default. Type: feature Signed-off-by: Steven Luong <sluong@cisco.com> Change-Id: I68dab7dd07045cafb49af97b7f70db9b8131ae03
Diffstat (limited to 'src/vnet/devices/virtio/vhost_user_inline.h')
-rw-r--r--src/vnet/devices/virtio/vhost_user_inline.h133
1 files changed, 122 insertions, 11 deletions
diff --git a/src/vnet/devices/virtio/vhost_user_inline.h b/src/vnet/devices/virtio/vhost_user_inline.h
index 17b6a90618f..5297453c317 100644
--- a/src/vnet/devices/virtio/vhost_user_inline.h
+++ b/src/vnet/devices/virtio/vhost_user_inline.h
@@ -248,8 +248,20 @@ format_vhost_trace (u8 * s, va_list * va)
return s;
}
+static_always_inline u64
+vhost_user_is_packed_ring_supported (vhost_user_intf_t * vui)
+{
+ return (vui->features & VIRTIO_FEATURE (VIRTIO_F_RING_PACKED));
+}
+
+static_always_inline u64
+vhost_user_is_event_idx_supported (vhost_user_intf_t * vui)
+{
+ return (vui->features & VIRTIO_FEATURE (VIRTIO_RING_F_EVENT_IDX));
+}
+
static_always_inline void
-vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq)
+vhost_user_kick (vlib_main_t * vm, vhost_user_vring_t * vq)
{
vhost_user_main_t *vum = &vhost_user_main;
u64 x = 1;
@@ -257,7 +269,7 @@ vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq)
int rv;
rv = write (fd, &x, sizeof (x));
- if (rv <= 0)
+ if (PREDICT_FALSE (rv <= 0))
{
clib_unix_warning
("Error: Could not write to unix socket for callfd %d", fd);
@@ -268,6 +280,101 @@ vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq)
vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time;
}
+static_always_inline u16
+vhost_user_avail_event_idx (vhost_user_vring_t * vq)
+{
+ volatile u16 *event_idx = (u16 *) & (vq->used->ring[vq->qsz_mask + 1]);
+
+ return *event_idx;
+}
+
+static_always_inline u16
+vhost_user_used_event_idx (vhost_user_vring_t * vq)
+{
+ volatile u16 *event_idx = (u16 *) & (vq->avail->ring[vq->qsz_mask + 1]);
+
+ return *event_idx;
+}
+
+static_always_inline u16
+vhost_user_need_event (u16 event_idx, u16 new_idx, u16 old_idx)
+{
+ return ((u16) (new_idx - event_idx - 1) < (u16) (new_idx - old_idx));
+}
+
+static_always_inline void
+vhost_user_send_call_event_idx (vlib_main_t * vm, vhost_user_vring_t * vq)
+{
+ vhost_user_main_t *vum = &vhost_user_main;
+ u8 first_kick = vq->first_kick;
+ u16 event_idx = vhost_user_used_event_idx (vq);
+
+ vq->first_kick = 1;
+ if (vhost_user_need_event (event_idx, vq->last_used_idx, vq->last_kick) ||
+ PREDICT_FALSE (!first_kick))
+ {
+ vhost_user_kick (vm, vq);
+ vq->last_kick = event_idx;
+ }
+ else
+ {
+ vq->n_since_last_int = 0;
+ vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time;
+ }
+}
+
+static_always_inline void
+vhost_user_send_call_event_idx_packed (vlib_main_t * vm,
+ vhost_user_vring_t * vq)
+{
+ vhost_user_main_t *vum = &vhost_user_main;
+ u8 first_kick = vq->first_kick;
+ u16 off_wrap;
+ u16 event_idx;
+ u16 new_idx = vq->last_used_idx;
+ u16 old_idx = vq->last_kick;
+
+ if (PREDICT_TRUE (vq->avail_event->flags == VRING_EVENT_F_DESC))
+ {
+ CLIB_COMPILER_BARRIER ();
+ off_wrap = vq->avail_event->off_wrap;
+ event_idx = off_wrap & 0x7fff;
+ if (vq->used_wrap_counter != (off_wrap >> 15))
+ event_idx -= (vq->qsz_mask + 1);
+
+ if (new_idx <= old_idx)
+ old_idx -= (vq->qsz_mask + 1);
+
+ vq->first_kick = 1;
+ vq->last_kick = event_idx;
+ if (vhost_user_need_event (event_idx, new_idx, old_idx) ||
+ PREDICT_FALSE (!first_kick))
+ vhost_user_kick (vm, vq);
+ else
+ {
+ vq->n_since_last_int = 0;
+ vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time;
+ }
+ }
+ else
+ vhost_user_kick (vm, vq);
+}
+
+static_always_inline void
+vhost_user_send_call (vlib_main_t * vm, vhost_user_intf_t * vui,
+ vhost_user_vring_t * vq)
+{
+ if (vhost_user_is_event_idx_supported (vui))
+ {
+ if (vhost_user_is_packed_ring_supported (vui))
+ vhost_user_send_call_event_idx_packed (vm, vq);
+ else
+ vhost_user_send_call_event_idx (vm, vq);
+ }
+ else
+ vhost_user_kick (vm, vq);
+}
+
static_always_inline u8
vui_is_link_up (vhost_user_intf_t * vui)
{
@@ -305,7 +412,10 @@ vhost_user_advance_last_avail_idx (vhost_user_vring_t * vring)
{
vring->last_avail_idx++;
if (PREDICT_FALSE ((vring->last_avail_idx & vring->qsz_mask) == 0))
- vring->avail_wrap_counter ^= VRING_DESC_F_AVAIL;
+ {
+ vring->avail_wrap_counter ^= VRING_DESC_F_AVAIL;
+ vring->last_avail_idx = 0;
+ }
}
static_always_inline void
@@ -331,7 +441,11 @@ vhost_user_undo_advanced_last_avail_idx (vhost_user_vring_t * vring)
{
if (PREDICT_FALSE ((vring->last_avail_idx & vring->qsz_mask) == 0))
vring->avail_wrap_counter ^= VRING_DESC_F_AVAIL;
- vring->last_avail_idx--;
+
+ if (PREDICT_FALSE (vring->last_avail_idx == 0))
+ vring->last_avail_idx = vring->qsz_mask;
+ else
+ vring->last_avail_idx--;
}
static_always_inline void
@@ -362,13 +476,10 @@ vhost_user_advance_last_used_idx (vhost_user_vring_t * vring)
{
vring->last_used_idx++;
if (PREDICT_FALSE ((vring->last_used_idx & vring->qsz_mask) == 0))
- vring->used_wrap_counter ^= 1;
-}
-
-static_always_inline u64
-vhost_user_is_packed_ring_supported (vhost_user_intf_t * vui)
-{
- return (vui->features & VIRTIO_FEATURE (VIRTIO_F_RING_PACKED));
+ {
+ vring->used_wrap_counter ^= 1;
+ vring->last_used_idx = 0;
+ }
}
#endif