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[bhyve] virtio-net: Do not allow receiving packets until features have been negotiated.

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Enforce the requirement that the RX callback cannot be called after a reset until the features have been negotiated.
This fixes a race condition where the receive callback is called during a device reset.

Reviewed by:	vmaffione, grehan
Approved by:	vmaffione (mentor)
Sponsored by:	vstack.com
Differential Revision:	https://reviews.freebsd.org/D27381
This commit is contained in:
afedorov 2020-12-17 16:52:40 +00:00
parent 188e59845a
commit 29679793ce
1 changed files with 19 additions and 0 deletions
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19
usr.sbin/bhyve/pci_virtio_net.c
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@ -111,6 +111,8 @@ struct pci_vtnet_softc {
net_backend_t *vsc_be;
bool features_negotiated; /* protected by rx_mtx */
int resetting; /* protected by tx_mtx */
uint64_t vsc_features; /* negotiated features */
@ -176,6 +178,7 @@ pci_vtnet_reset(void *vsc)
* Receive operation will be enabled again once the guest adds
* the first receive buffers and kicks us.
*/
sc->features_negotiated = false;
netbe_rx_disable(sc->vsc_be);
/* Set sc->resetting and give a chance to the TX thread to stop. */
@ -246,6 +249,12 @@ pci_vtnet_rx(struct pci_vtnet_softc *sc)
struct vqueue_info *vq;
vq = &sc->vsc_queues[VTNET_RXQ];
/* Features must be negotiated */
if (!sc->features_negotiated) {
return;
}
for (;;) {
struct virtio_net_rxhdr *hdr;
uint32_t riov_bytes;
@ -406,8 +415,14 @@ pci_vtnet_ping_rxq(void *vsc, struct vqueue_info *vq)
/*
* A qnotify means that the rx process can now begin.
* Enable RX only if features are negotiated.
*/
pthread_mutex_lock(&sc->rx_mtx);
if (!sc->features_negotiated) {
pthread_mutex_unlock(&sc->rx_mtx);
return;
}
vq_kick_disable(vq);
netbe_rx_enable(sc->vsc_be);
pthread_mutex_unlock(&sc->rx_mtx);
@ -750,6 +765,10 @@ pci_vtnet_neg_features(void *vsc, uint64_t negotiated_features)
netbe_set_cap(sc->vsc_be, negotiated_features, sc->vhdrlen);
sc->be_vhdrlen = netbe_get_vnet_hdr_len(sc->vsc_be);
assert(sc->be_vhdrlen == 0 || sc->be_vhdrlen == sc->vhdrlen);
pthread_mutex_lock(&sc->rx_mtx);
sc->features_negotiated = true;
pthread_mutex_unlock(&sc->rx_mtx);
}
#ifdef BHYVE_SNAPSHOT