svn commit: r354864 - head/usr.sbin/bhyve
Vincenzo Maffione
vmaffione at FreeBSD.org
Tue Nov 19 21:10:44 UTC 2019
Author: vmaffione
Date: Tue Nov 19 21:10:44 2019
New Revision: 354864
URL: https://svnweb.freebsd.org/changeset/base/354864
Log:
bhyve: virtio-net: disable receive until features are negotiated
This patch fixes a race condition where the receive callback is called
while the device is being reset. Since the rx_merge variable may change
during reset, the receive callback may operate inconsistently with what
the guest expects.
Also, get rid of the unused rx_vhdrlen variable.
PR: 242023
Reported by: aleksandr.fedorov at itglobal.com
Reviewed by: markj, jhb
MFC with: r354552
Differential Revision: https://reviews.freebsd.org/D22440
Modified:
head/usr.sbin/bhyve/pci_virtio_net.c
Modified: head/usr.sbin/bhyve/pci_virtio_net.c
==============================================================================
--- head/usr.sbin/bhyve/pci_virtio_net.c Tue Nov 19 21:08:18 2019 (r354863)
+++ head/usr.sbin/bhyve/pci_virtio_net.c Tue Nov 19 21:10:44 2019 (r354864)
@@ -109,7 +109,6 @@ struct pci_vtnet_softc {
uint64_t vsc_features; /* negotiated features */
pthread_mutex_t rx_mtx;
- unsigned int rx_vhdrlen;
int rx_merge; /* merged rx bufs in use */
pthread_t tx_tid;
@@ -149,6 +148,16 @@ pci_vtnet_reset(void *vsc)
/* Acquire the RX lock to block RX processing. */
pthread_mutex_lock(&sc->rx_mtx);
+ /*
+ * Make sure receive operation is disabled at least until we
+ * re-negotiate the features, since receive operation depends
+ * on the value of sc->rx_merge and the header length, which
+ * are both set in pci_vtnet_neg_features().
+ * Receive operation will be enabled again once the guest adds
+ * the first receive buffers and kicks us.
+ */
+ netbe_rx_disable(sc->vsc_be);
+
/* Set sc->resetting and give a chance to the TX thread to stop. */
pthread_mutex_lock(&sc->tx_mtx);
sc->resetting = 1;
@@ -158,9 +167,6 @@ pci_vtnet_reset(void *vsc)
pthread_mutex_lock(&sc->tx_mtx);
}
- sc->rx_merge = 1;
- sc->rx_vhdrlen = sizeof(struct virtio_net_rxhdr);
-
/*
* Now reset rings, MSI-X vectors, and negotiated capabilities.
* Do that with the TX lock held, since we need to reset
@@ -512,8 +518,7 @@ pci_vtnet_init(struct vmctx *ctx, struct pci_devinst *
sc->resetting = 0;
- sc->rx_merge = 1;
- sc->rx_vhdrlen = sizeof(struct virtio_net_rxhdr);
+ sc->rx_merge = 0;
pthread_mutex_init(&sc->rx_mtx, NULL);
/*
@@ -568,18 +573,24 @@ static void
pci_vtnet_neg_features(void *vsc, uint64_t negotiated_features)
{
struct pci_vtnet_softc *sc = vsc;
+ unsigned int rx_vhdrlen;
sc->vsc_features = negotiated_features;
- if (!(negotiated_features & VIRTIO_NET_F_MRG_RXBUF)) {
+ if (negotiated_features & VIRTIO_NET_F_MRG_RXBUF) {
+ rx_vhdrlen = sizeof(struct virtio_net_rxhdr);
+ sc->rx_merge = 1;
+ } else {
+ /*
+ * Without mergeable rx buffers, virtio-net header is 2
+ * bytes shorter than sizeof(struct virtio_net_rxhdr).
+ */
+ rx_vhdrlen = sizeof(struct virtio_net_rxhdr) - 2;
sc->rx_merge = 0;
- /* Without mergeable rx buffers, virtio-net header is 2
- * bytes shorter than sizeof(struct virtio_net_rxhdr). */
- sc->rx_vhdrlen = sizeof(struct virtio_net_rxhdr) - 2;
}
/* Tell the backend to enable some capabilities it has advertised. */
- netbe_set_cap(sc->vsc_be, negotiated_features, sc->rx_vhdrlen);
+ netbe_set_cap(sc->vsc_be, negotiated_features, rx_vhdrlen);
}
static struct pci_devemu pci_de_vnet = {
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