Module Name: src
Committed By: ozaki-r
Date: Mon Oct 26 01:44:48 UTC 2015
Modified Files:
src/sys/dev/pci: if_vioif.c virtio.c virtioreg.h virtiovar.h
Log Message:
Support MSI-X in virtio
Currently only vioif(4) uses the feature.
knakahara@ helped to migrate to pci_intr_alloc(9). Thanks!
To generate a diff of this commit:
cvs rdiff -u -r1.16 -r1.17 src/sys/dev/pci/if_vioif.c
cvs rdiff -u -r1.10 -r1.11 src/sys/dev/pci/virtio.c
cvs rdiff -u -r1.3 -r1.4 src/sys/dev/pci/virtioreg.h
cvs rdiff -u -r1.4 -r1.5 src/sys/dev/pci/virtiovar.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/pci/if_vioif.c
diff -u src/sys/dev/pci/if_vioif.c:1.16 src/sys/dev/pci/if_vioif.c:1.17
--- src/sys/dev/pci/if_vioif.c:1.16 Tue May 5 10:56:13 2015
+++ src/sys/dev/pci/if_vioif.c Mon Oct 26 01:44:48 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: if_vioif.c,v 1.16 2015/05/05 10:56:13 ozaki-r Exp $ */
+/* $NetBSD: if_vioif.c,v 1.17 2015/10/26 01:44:48 ozaki-r Exp $ */
/*
* Copyright (c) 2010 Minoura Makoto.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_vioif.c,v 1.16 2015/05/05 10:56:13 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_vioif.c,v 1.17 2015/10/26 01:44:48 ozaki-r Exp $");
#ifdef _KERNEL_OPT
#include "opt_net_mpsafe.h"
@@ -487,6 +487,7 @@ vioif_attach(device_t parent, device_t s
uint32_t features;
struct ifnet *ifp = &sc->sc_ethercom.ec_if;
u_int flags;
+ int r;
if (vsc->sc_child != NULL) {
aprint_normal(": child already attached for %s; "
@@ -511,6 +512,7 @@ vioif_attach(device_t parent, device_t s
#ifdef VIOIF_SOFTINT_INTR
vsc->sc_flags |= VIRTIO_F_PCI_INTR_SOFTINT;
#endif
+ vsc->sc_flags |= VIRTIO_F_PCI_INTR_MSIX;
features = virtio_negotiate_features(vsc,
(VIRTIO_NET_F_MAC |
@@ -560,21 +562,6 @@ vioif_attach(device_t parent, device_t s
aprint_normal(": Ethernet address %s\n", ether_sprintf(sc->sc_mac));
aprint_naive("\n");
- if (virtio_alloc_vq(vsc, &sc->sc_vq[0], 0,
- MCLBYTES+sizeof(struct virtio_net_hdr), 2,
- "rx") != 0) {
- goto err;
- }
- vsc->sc_nvqs = 1;
- sc->sc_vq[0].vq_done = vioif_rx_vq_done;
- if (virtio_alloc_vq(vsc, &sc->sc_vq[1], 1,
- (sizeof(struct virtio_net_hdr)
- + (ETHER_MAX_LEN - ETHER_HDR_LEN)),
- VIRTIO_NET_TX_MAXNSEGS + 1,
- "tx") != 0) {
- goto err;
- }
-
#ifdef VIOIF_MPSAFE
sc->sc_tx_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NET);
sc->sc_rx_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NET);
@@ -584,23 +571,51 @@ vioif_attach(device_t parent, device_t s
#endif
sc->sc_stopping = false;
+ /*
+ * Allocating a virtqueue for Rx
+ */
+ r = virtio_alloc_vq(vsc, &sc->sc_vq[0], 0,
+ MCLBYTES+sizeof(struct virtio_net_hdr), 2, "rx");
+ if (r != 0)
+ goto err;
+ vsc->sc_nvqs = 1;
+ sc->sc_vq[0].vq_done = vioif_rx_vq_done;
+
+ /*
+ * Allocating a virtqueue for Tx
+ */
+ r = virtio_alloc_vq(vsc, &sc->sc_vq[1], 1,
+ (sizeof(struct virtio_net_hdr) + (ETHER_MAX_LEN - ETHER_HDR_LEN)),
+ VIRTIO_NET_TX_MAXNSEGS + 1, "tx");
+ if (r != 0)
+ goto err;
vsc->sc_nvqs = 2;
sc->sc_vq[1].vq_done = vioif_tx_vq_done;
+
virtio_start_vq_intr(vsc, &sc->sc_vq[0]);
virtio_stop_vq_intr(vsc, &sc->sc_vq[1]); /* not urgent; do it later */
- if ((features & VIRTIO_NET_F_CTRL_VQ)
- && (features & VIRTIO_NET_F_CTRL_RX)) {
- if (virtio_alloc_vq(vsc, &sc->sc_vq[2], 2,
- NBPG, 1, "control") == 0) {
- sc->sc_vq[2].vq_done = vioif_ctrl_vq_done;
- cv_init(&sc->sc_ctrl_wait, "ctrl_vq");
- mutex_init(&sc->sc_ctrl_wait_lock,
- MUTEX_DEFAULT, IPL_NET);
- sc->sc_ctrl_inuse = FREE;
- virtio_start_vq_intr(vsc, &sc->sc_vq[2]);
- vsc->sc_nvqs = 3;
+
+ if ((features & VIRTIO_NET_F_CTRL_VQ) &&
+ (features & VIRTIO_NET_F_CTRL_RX)) {
+ /*
+ * Allocating a virtqueue for control channel
+ */
+ r = virtio_alloc_vq(vsc, &sc->sc_vq[2], 2,
+ NBPG, 1, "control");
+ if (r != 0) {
+ aprint_error_dev(self, "failed to allocate "
+ "a virtqueue for control channel\n");
+ goto skip;
}
+
+ sc->sc_vq[2].vq_done = vioif_ctrl_vq_done;
+ cv_init(&sc->sc_ctrl_wait, "ctrl_vq");
+ mutex_init(&sc->sc_ctrl_wait_lock, MUTEX_DEFAULT, IPL_NET);
+ sc->sc_ctrl_inuse = FREE;
+ virtio_start_vq_intr(vsc, &sc->sc_vq[2]);
+ vsc->sc_nvqs = 3;
}
+skip:
#ifdef VIOIF_MPSAFE
flags = SOFTINT_NET | SOFTINT_MPSAFE;
Index: src/sys/dev/pci/virtio.c
diff -u src/sys/dev/pci/virtio.c:1.10 src/sys/dev/pci/virtio.c:1.11
--- src/sys/dev/pci/virtio.c:1.10 Thu Oct 15 02:40:38 2015
+++ src/sys/dev/pci/virtio.c Mon Oct 26 01:44:48 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: virtio.c,v 1.10 2015/10/15 02:40:38 ozaki-r Exp $ */
+/* $NetBSD: virtio.c,v 1.11 2015/10/26 01:44:48 ozaki-r Exp $ */
/*
* Copyright (c) 2010 Minoura Makoto.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: virtio.c,v 1.10 2015/10/15 02:40:38 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: virtio.c,v 1.11 2015/10/26 01:44:48 ozaki-r Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -49,6 +49,15 @@ static int virtio_match(device_t, cfdata
static void virtio_attach(device_t, device_t, void *);
static int virtio_detach(device_t, int);
static int virtio_intr(void *arg);
+static int virtio_msix_queue_intr(void *);
+static int virtio_msix_config_intr(void *);
+static int virtio_setup_msix_vectors(struct virtio_softc *);
+static int virtio_setup_msix_interrupts(struct virtio_softc *,
+ struct pci_attach_args *);
+static int virtio_setup_intx_interrupt(struct virtio_softc *,
+ struct pci_attach_args *);
+static int virtio_setup_interrupts(struct virtio_softc *,
+ struct pci_attach_args *);
static void virtio_soft_intr(void *arg);
static void virtio_init_vq(struct virtio_softc *,
struct virtqueue *, const bool);
@@ -104,6 +113,203 @@ static const char *virtio_device_name[]
};
#define NDEVNAMES (sizeof(virtio_device_name)/sizeof(char*))
+#define VIRTIO_MSIX_CONFIG_VECTOR_INDEX 0
+#define VIRTIO_MSIX_QUEUE_VECTOR_INDEX 1
+
+static int
+virtio_setup_msix_vectors(struct virtio_softc *sc)
+{
+ int offset, vector, ret, qid;
+
+ offset = VIRTIO_CONFIG_MSI_CONFIG_VECTOR;
+ vector = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
+
+ bus_space_write_2(sc->sc_iot, sc->sc_ioh, offset, vector);
+ ret = bus_space_read_2(sc->sc_iot, sc->sc_ioh, offset);
+ aprint_debug_dev(sc->sc_dev, "expected=%d, actual=%d\n",
+ vector, ret);
+ if (ret != vector)
+ return -1;
+
+ for (qid = 0; qid < sc->sc_nvqs; qid++) {
+ offset = VIRTIO_CONFIG_QUEUE_SELECT;
+ bus_space_write_2(sc->sc_iot, sc->sc_ioh, offset, qid);
+
+ offset = VIRTIO_CONFIG_MSI_QUEUE_VECTOR;
+ vector = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
+
+ bus_space_write_2(sc->sc_iot, sc->sc_ioh, offset, vector);
+ ret = bus_space_read_2(sc->sc_iot, sc->sc_ioh, offset);
+ aprint_debug_dev(sc->sc_dev, "expected=%d, actual=%d\n",
+ vector, ret);
+ if (ret != vector)
+ return -1;
+ }
+
+ return 0;
+}
+
+static int
+virtio_setup_msix_interrupts(struct virtio_softc *sc,
+ struct pci_attach_args *pa)
+{
+ device_t self = sc->sc_dev;
+ pci_chipset_tag_t pc = pa->pa_pc;
+ char intrbuf[PCI_INTRSTR_LEN];
+ char const *intrstr;
+ int idx;
+
+ idx = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
+ if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
+ pci_intr_setattr(pc, &sc->sc_ihp[idx], PCI_INTR_MPSAFE, true);
+
+ sc->sc_ihs[idx] = pci_intr_establish_xname(pc, sc->sc_ihp[idx], IPL_NET,
+ virtio_msix_config_intr, sc, device_xname(sc->sc_dev));
+ if (sc->sc_ihs[idx] == NULL) {
+ aprint_error_dev(self, "couldn't establish MSI-X for config\n");
+ goto error;
+ }
+
+ idx = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
+ if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
+ pci_intr_setattr(pc, &sc->sc_ihp[idx], PCI_INTR_MPSAFE, true);
+
+ sc->sc_ihs[idx] = pci_intr_establish_xname(pc, sc->sc_ihp[idx], IPL_NET,
+ virtio_msix_queue_intr, sc, device_xname(sc->sc_dev));
+ if (sc->sc_ihs[idx] == NULL) {
+ aprint_error_dev(self, "couldn't establish MSI-X for queues\n");
+ goto error;
+ }
+
+ if (virtio_setup_msix_vectors(sc) != 0) {
+ aprint_error_dev(self, "couldn't setup MSI-X vectors\n");
+ goto error;
+ }
+
+ idx = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
+ intrstr = pci_intr_string(pc, sc->sc_ihp[idx], intrbuf, sizeof(intrbuf));
+ aprint_normal_dev(self, "config interrupting at %s\n", intrstr);
+ idx = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
+ intrstr = pci_intr_string(pc, sc->sc_ihp[idx], intrbuf, sizeof(intrbuf));
+ aprint_normal_dev(self, "queues interrupting at %s\n", intrstr);
+
+ return 0;
+
+error:
+ idx = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
+ if (sc->sc_ihs[idx] != NULL)
+ pci_intr_disestablish(sc->sc_pc, sc->sc_ihs[idx]);
+ idx = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
+ if (sc->sc_ihs[idx] != NULL)
+ pci_intr_disestablish(sc->sc_pc, sc->sc_ihs[idx]);
+
+ return -1;
+}
+
+static int
+virtio_setup_intx_interrupt(struct virtio_softc *sc, struct pci_attach_args *pa)
+{
+ device_t self = sc->sc_dev;
+ pci_chipset_tag_t pc = pa->pa_pc;
+ char intrbuf[PCI_INTRSTR_LEN];
+ char const *intrstr;
+
+ if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
+ pci_intr_setattr(pc, &sc->sc_ihp[0], PCI_INTR_MPSAFE, true);
+
+ sc->sc_ihs[0] = pci_intr_establish_xname(pc, sc->sc_ihp[0],
+ IPL_NET, virtio_intr, sc, device_xname(sc->sc_dev));
+ if (sc->sc_ihs[0] == NULL) {
+ aprint_error_dev(self, "couldn't establish INTx\n");
+ return -1;
+ }
+
+ intrstr = pci_intr_string(pc, sc->sc_ihp[0], intrbuf, sizeof(intrbuf));
+ aprint_normal_dev(self, "interrupting at %s\n", intrstr);
+
+ return 0;
+}
+
+static int
+virtio_setup_interrupts(struct virtio_softc *sc, struct pci_attach_args *pa)
+{
+ device_t self = sc->sc_dev;
+ pci_chipset_tag_t pc = pa->pa_pc;
+ int error;
+ int nmsix;
+ int counts[PCI_INTR_TYPE_SIZE];
+ pci_intr_type_t max_type;
+
+ nmsix = pci_msix_count(pa->pa_pc, pa->pa_tag);
+ aprint_debug_dev(self, "pci_msix_count=%d\n", nmsix);
+
+ /* We need at least two: one for config and the other for queues */
+ if ((sc->sc_flags & VIRTIO_F_PCI_INTR_MSIX) == 0 || nmsix < 2) {
+ /* Try INTx only */
+ max_type = PCI_INTR_TYPE_INTX;
+ counts[PCI_INTR_TYPE_INTX] = 1;
+ } else {
+ /* Try MSI-X first and INTx second */
+ max_type = PCI_INTR_TYPE_MSIX;
+ counts[PCI_INTR_TYPE_MSIX] = 2;
+ counts[PCI_INTR_TYPE_MSI] = 0;
+ counts[PCI_INTR_TYPE_INTX] = 1;
+ }
+
+ retry:
+ error = pci_intr_alloc(pa, &sc->sc_ihp, counts, max_type);
+ if (error != 0) {
+ aprint_error_dev(self, "couldn't map interrupt\n");
+ return -1;
+ }
+
+ if (pci_intr_type(sc->sc_ihp[0]) == PCI_INTR_TYPE_MSIX) {
+ sc->sc_ihs = kmem_alloc(sizeof(*sc->sc_ihs) * 2,
+ KM_SLEEP);
+ if (sc->sc_ihs == NULL) {
+ pci_intr_release(pc, sc->sc_ihp, 2);
+
+ /* Retry INTx */
+ max_type = PCI_INTR_TYPE_INTX;
+ counts[PCI_INTR_TYPE_INTX] = 1;
+ goto retry;
+ }
+
+ error = virtio_setup_msix_interrupts(sc, pa);
+ if (error != 0) {
+ kmem_free(sc->sc_ihs, sizeof(*sc->sc_ihs) * 2);
+ pci_intr_release(pc, sc->sc_ihp, 2);
+
+ /* Retry INTx */
+ max_type = PCI_INTR_TYPE_INTX;
+ counts[PCI_INTR_TYPE_INTX] = 1;
+ goto retry;
+ }
+
+ sc->sc_ihs_num = 2;
+ sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_MSI;
+ } else if (pci_intr_type(sc->sc_ihp[0]) == PCI_INTR_TYPE_INTX) {
+ sc->sc_ihs = kmem_alloc(sizeof(*sc->sc_ihs) * 1,
+ KM_SLEEP);
+ if (sc->sc_ihs == NULL) {
+ pci_intr_release(pc, sc->sc_ihp, 1);
+ return -1;
+ }
+
+ error = virtio_setup_intx_interrupt(sc, pa);
+ if (error != 0) {
+ kmem_free(sc->sc_ihs, sizeof(*sc->sc_ihs) * 1);
+ pci_intr_release(pc, sc->sc_ihp, 1);
+ return -1;
+ }
+
+ sc->sc_ihs_num = 1;
+ sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI;
+ }
+
+ return 0;
+}
+
static void
virtio_attach(device_t parent, device_t self, void *aux)
{
@@ -113,9 +319,7 @@ virtio_attach(device_t parent, device_t
pcitag_t tag = pa->pa_tag;
int revision;
pcireg_t id;
- char const *intrstr;
- pci_intr_handle_t ih;
- char intrbuf[PCI_INTRSTR_LEN];
+ int r;
revision = PCI_REVISION(pa->pa_class);
if (revision != 0) {
@@ -166,29 +370,12 @@ virtio_attach(device_t parent, device_t
return;
}
- if (pci_intr_map(pa, &ih)) {
- aprint_error_dev(self, "couldn't map interrupt\n");
- virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_FAILED);
- return;
- }
-
- intrstr = pci_intr_string(pc, ih, intrbuf, sizeof(intrbuf));
-
- if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
- pci_intr_setattr(pc, &ih, PCI_INTR_MPSAFE, true);
-
- sc->sc_ih = pci_intr_establish_xname(pc, ih, sc->sc_ipl, virtio_intr, sc,
- device_xname(sc->sc_dev));
-
- if (sc->sc_ih == NULL) {
- aprint_error_dev(self, "couldn't establish interrupt");
- if (intrstr != NULL)
- aprint_error(" at %s", intrstr);
- aprint_error("\n");
+ r = virtio_setup_interrupts(sc, pa);
+ if (r != 0) {
+ aprint_error_dev(self, "failed to setup interrupts\n");
virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_FAILED);
return;
}
- aprint_normal_dev(self, "interrupting at %s\n", intrstr);
sc->sc_soft_ih = NULL;
if (sc->sc_flags & VIRTIO_F_PCI_INTR_SOFTINT) {
@@ -211,6 +398,7 @@ virtio_detach(device_t self, int flags)
{
struct virtio_softc *sc = device_private(self);
int r;
+ int i;
if (sc->sc_child != 0 && sc->sc_child != (void*)1) {
r = config_detach(sc->sc_child, flags);
@@ -219,10 +407,14 @@ virtio_detach(device_t self, int flags)
}
KASSERT(sc->sc_child == 0 || sc->sc_child == (void*)1);
KASSERT(sc->sc_vqs == 0);
- if (sc->sc_ih != NULL) {
- pci_intr_disestablish(sc->sc_pc, sc->sc_ih);
- sc->sc_ih = NULL;
+ for (i = 0; i < sc->sc_ihs_num; i++) {
+ if (sc->sc_ihs[i] == NULL)
+ continue;
+ pci_intr_disestablish(sc->sc_pc, sc->sc_ihs[i]);
}
+ pci_intr_release(sc->sc_pc, sc->sc_ihp, sc->sc_ihs_num);
+ kmem_free(sc->sc_ihs, sizeof(*sc->sc_ihs) * sc->sc_ihs_num);
+ sc->sc_ihs_num = 0;
if (sc->sc_iosize)
bus_space_unmap(sc->sc_iot, sc->sc_ioh, sc->sc_iosize);
sc->sc_iosize = 0;
@@ -278,6 +470,14 @@ virtio_reinit_start(struct virtio_softc
(vq->vq_dmamap->dm_segs[0].ds_addr
/ VIRTIO_PAGE_SIZE));
}
+
+ /* MSI-X should have more than one handles where INTx has just one */
+ if (sc->sc_ihs_num > 1) {
+ if (virtio_setup_msix_vectors(sc) != 0) {
+ aprint_error_dev(sc->sc_dev, "couldn't setup MSI-X vectors\n");
+ return;
+ }
+ }
}
void
@@ -411,6 +611,32 @@ virtio_intr(void *arg)
return r;
}
+static int
+virtio_msix_queue_intr(void *arg)
+{
+ struct virtio_softc *sc = arg;
+ int r = 0;
+
+ if (sc->sc_intrhand != NULL) {
+ if (sc->sc_soft_ih != NULL)
+ softint_schedule(sc->sc_soft_ih);
+ else
+ r |= (sc->sc_intrhand)(sc);
+ }
+
+ return r;
+}
+
+static int
+virtio_msix_config_intr(void *arg)
+{
+ struct virtio_softc *sc = arg;
+
+ /* TODO: handle events */
+ aprint_debug_dev(sc->sc_dev, "%s\n", __func__);
+ return 1;
+}
+
static void
virtio_soft_intr(void *arg)
{
Index: src/sys/dev/pci/virtioreg.h
diff -u src/sys/dev/pci/virtioreg.h:1.3 src/sys/dev/pci/virtioreg.h:1.4
--- src/sys/dev/pci/virtioreg.h:1.3 Mon May 4 14:08:57 2015
+++ src/sys/dev/pci/virtioreg.h Mon Oct 26 01:44:48 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: virtioreg.h,v 1.3 2015/05/04 14:08:57 ozaki-r Exp $ */
+/* $NetBSD: virtioreg.h,v 1.4 2015/10/26 01:44:48 ozaki-r Exp $ */
/*
* Copyright (c) 2010 Minoura Makoto.
@@ -96,6 +96,9 @@
#define VIRTIO_CONFIG_CONFIG_VECTOR 20 /* 16bit, optional */
#define VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI 20
#define VIRTIO_CONFIG_DEVICE_CONFIG_MSI 24
+/* MSI/MSI-X */
+#define VIRTIO_CONFIG_MSI_CONFIG_VECTOR 20
+#define VIRTIO_CONFIG_MSI_QUEUE_VECTOR 22
/* Virtqueue */
/* This marks a buffer as continuing via the next field. */
Index: src/sys/dev/pci/virtiovar.h
diff -u src/sys/dev/pci/virtiovar.h:1.4 src/sys/dev/pci/virtiovar.h:1.5
--- src/sys/dev/pci/virtiovar.h:1.4 Fri Dec 19 06:54:40 2014
+++ src/sys/dev/pci/virtiovar.h Mon Oct 26 01:44:48 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: virtiovar.h,v 1.4 2014/12/19 06:54:40 ozaki-r Exp $ */
+/* $NetBSD: virtiovar.h,v 1.5 2015/10/26 01:44:48 ozaki-r Exp $ */
/*
* Copyright (c) 2010 Minoura Makoto.
@@ -125,7 +125,9 @@ struct virtio_softc {
bus_dma_tag_t sc_dmat;
int sc_ipl; /* set by child */
- void *sc_ih;
+ pci_intr_handle_t *sc_ihp;
+ void **sc_ihs;
+ int sc_ihs_num;
void *sc_soft_ih;
int sc_flags; /* set by child */
@@ -151,6 +153,7 @@ struct virtio_softc {
#define VIRTIO_F_PCI_INTR_MPSAFE (1 << 0)
#define VIRTIO_F_PCI_INTR_SOFTINT (1 << 1)
+#define VIRTIO_F_PCI_INTR_MSIX (1 << 2)
/* public interface */
uint32_t virtio_negotiate_features(struct virtio_softc*, uint32_t);
