Author: neel
Date: Fri May 3 01:16:18 2013
New Revision: 250197
URL: http://svnweb.freebsd.org/changeset/base/250197
Log:
Implement the NOTIFY_ON_EMPTY capability in the virtio-net device.
If this capability is negotiated by the guest then the device will
generate an interrupt when it runs out of available tx/rx descriptors.
Reviewed by: grehan
Obtained from: NetApp
Modified:
head/usr.sbin/bhyve/pci_virtio_net.c
head/usr.sbin/bhyve/virtio.h
Modified: head/usr.sbin/bhyve/pci_virtio_net.c
==============================================================================
--- head/usr.sbin/bhyve/pci_virtio_net.c Thu May 2 21:51:57 2013
(r250196)
+++ head/usr.sbin/bhyve/pci_virtio_net.c Fri May 3 01:16:18 2013
(r250197)
@@ -78,7 +78,8 @@ __FBSDID("$FreeBSD$");
#define VTNET_S_HOSTCAPS \
( 0x00000020 | /* host supplies MAC */ \
0x00008000 | /* host can merge Rx buffers */ \
- 0x00010000 ) /* config status available */
+ 0x00010000 | /* config status available */ \
+ VIRTIO_F_NOTIFY_ON_EMPTY)
/*
* Queue definitions.
@@ -157,7 +158,8 @@ struct pci_vtnet_softc {
pthread_cond_t tx_cond;
int tx_in_progress;
};
-#define vtnet_ctx(sc) ((sc)->vsc_pi->pi_vmctx)
+#define vtnet_ctx(sc) ((sc)->vsc_pi->pi_vmctx)
+#define notify_on_empty(sc) ((sc)->vsc_features &
VIRTIO_F_NOTIFY_ON_EMPTY)
/*
* Return the size of IO BAR that maps virtio header and device specific
@@ -289,6 +291,18 @@ pci_vtnet_update_status(struct pci_vtnet
sc->vsc_status = value;
}
+static void
+vtnet_generate_interrupt(struct pci_vtnet_softc *sc, int qidx)
+{
+
+ if (use_msix) {
+ pci_generate_msix(sc->vsc_pi, sc->vsc_msix_table_idx[qidx]);
+ } else {
+ sc->vsc_isr |= 1;
+ pci_generate_msi(sc->vsc_pi, 0);
+ }
+}
+
/*
* Called to send a buffer chain out to the tap device
*/
@@ -366,6 +380,10 @@ pci_vtnet_tap_rx(struct pci_vtnet_softc
* Drop the packet and try later
*/
(void) read(sc->vsc_tapfd, dummybuf, sizeof(dummybuf));
+
+ if (notify_on_empty(sc))
+ vtnet_generate_interrupt(sc, VTNET_RXQ);
+
return;
}
@@ -418,15 +436,8 @@ pci_vtnet_tap_rx(struct pci_vtnet_softc
*hq->hq_used_idx = uidx;
hq->hq_cur_aidx = aidx;
- if ((*hq->hq_avail_flags & VRING_AVAIL_F_NO_INTERRUPT) == 0) {
- if (use_msix) {
- pci_generate_msix(sc->vsc_pi,
- sc->vsc_msix_table_idx[VTNET_RXQ]);
- } else {
- sc->vsc_isr |= 1;
- pci_generate_msi(sc->vsc_pi, 0);
- }
- }
+ if ((*hq->hq_avail_flags & VRING_AVAIL_F_NO_INTERRUPT) == 0)
+ vtnet_generate_interrupt(sc, VTNET_RXQ);
}
static void
@@ -536,9 +547,8 @@ pci_vtnet_tx_thread(void *param)
{
struct pci_vtnet_softc *sc = (struct pci_vtnet_softc *) param;
struct vring_hqueue *hq;
- int i, ndescs, needintr,error;
+ int i, ndescs, error;
- needintr = 0;
hq = &sc->vsc_hq[VTNET_TXQ];
/*
@@ -552,31 +562,14 @@ pci_vtnet_tx_thread(void *param)
for (;;) {
pthread_mutex_lock(&sc->tx_mtx);
for (;;) {
- if (sc->resetting) {
+ if (sc->resetting)
ndescs = 0;
- needintr = 0;
- } else
+ else
ndescs = hq_num_avail(hq);
if (ndescs != 0)
break;
-
- if (needintr) {
- /*
- * Generate an interrupt if able
- */
- if ((*hq->hq_avail_flags &
- VRING_AVAIL_F_NO_INTERRUPT) == 0) {
- if (use_msix) {
- pci_generate_msix(sc->vsc_pi,
-
sc->vsc_msix_table_idx[VTNET_TXQ]);
- } else {
- sc->vsc_isr |= 1;
- pci_generate_msi(sc->vsc_pi, 0);
- }
- }
- }
- needintr = 0;
+
sc->tx_in_progress = 0;
error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx);
assert(error == 0);
@@ -591,9 +584,16 @@ pci_vtnet_tx_thread(void *param)
*/
for (i = 0; i < ndescs; i++)
pci_vtnet_proctx(sc, hq);
- needintr = 1;
+
ndescs = hq_num_avail(hq);
}
+
+ /*
+ * Generate an interrupt if needed.
+ */
+ if (notify_on_empty(sc) ||
+ (*hq->hq_avail_flags & VRING_AVAIL_F_NO_INTERRUPT) == 0)
+ vtnet_generate_interrupt(sc, VTNET_TXQ);
}
}
Modified: head/usr.sbin/bhyve/virtio.h
==============================================================================
--- head/usr.sbin/bhyve/virtio.h Thu May 2 21:51:57 2013
(r250196)
+++ head/usr.sbin/bhyve/virtio.h Fri May 3 01:16:18 2013
(r250197)
@@ -85,6 +85,9 @@ struct virtio_used {
#define VTCFG_R_CFG1 24 /* With MSI-X */
#define VTCFG_R_MSIX 20
+/* Feature flags */
+#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)
+
/* From section 2.3, "Virtqueue Configuration", of the virtio specification */
static inline u_int
vring_size(u_int qsz)
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