Move legacy interrupt allocation for virtio devices to common code.

There are a number of assumptions about legacy interrupts always
being available in virtio so don't allow back-ends to make the
decision to support them.

This fixes the issue seen with virtio-rnd on OpenBSD. MSI-x vectors
were not being used, and the virtio-rnd backend wasn't allocating a
legacy interrupt resulting in a bhyve assert and guest exit.

Reported by:	Julian Hsiao, madoka at nyanisore dot net
Reviewed by:	neel
MFC after:	1 week

3 files changed, 5 insertions, 4 deletions

diff --git a/usr.sbin/bhyve/pci_virtio_block.c b/usr.sbin/bhyve/pci_virtio_block.c
index 985272b..967b528 100644
--- a/usr.sbin/bhyve/pci_virtio_block.c
+++ b/usr.sbin/bhyve/pci_virtio_block.c
@@ -370,8 +370,6 @@ pci_vtblk_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
 	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_STORAGE);
 	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_BLOCK);
 
-	pci_lintr_request(pi);
-
 	if (vi_intr_init(&sc->vbsc_vs, 1, fbsdrun_virtio_msix())) {
 		blockif_close(sc->bc);
 		free(sc);
diff --git a/usr.sbin/bhyve/pci_virtio_net.c b/usr.sbin/bhyve/pci_virtio_net.c
index f3656b7..457a405 100644
--- a/usr.sbin/bhyve/pci_virtio_net.c
+++ b/usr.sbin/bhyve/pci_virtio_net.c
@@ -640,8 +640,6 @@ pci_vtnet_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
 	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_NETWORK);
 	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_NET);
 
-	pci_lintr_request(pi);
-
 	/* link always up */
 	sc->vsc_config.status = 1;
 	
diff --git a/usr.sbin/bhyve/virtio.c b/usr.sbin/bhyve/virtio.c
index e985805..41a9e42 100644
--- a/usr.sbin/bhyve/virtio.c
+++ b/usr.sbin/bhyve/virtio.c
@@ -148,8 +148,13 @@ vi_intr_init(struct virtio_softc *vs, int barnum, int use_msix)
 			return (1);
 	} else
 		vs->vs_flags &= ~VIRTIO_USE_MSIX;
+
 	/* Only 1 MSI vector for bhyve */
 	pci_emul_add_msicap(vs->vs_pi, 1);
+
+	/* Legacy interrupts are mandatory for virtio devices */
+	pci_lintr_request(vs->vs_pi);
+
 	return (0);
 }