Author: vmaffione Date: Tue Jun 11 15:52:41 2019 New Revision: 348929 URL: https://svnweb.freebsd.org/changeset/base/348929
Log: bhyve: virtio: introduce vq_kick_enable() and vq_kick_disable() The VirtIO standard supports two schemes for notification suppression: a notification enable bit and a more sophisticated one (event_idx) that also supports delayed notifications. Currently bhyve fully supports only the first scheme. This patch hides the notification suppression internals by means of two inline routines, vq_kick_enable() and vq_kick_disable(), and makes the code more readable. Moreover, further improve readability by replacing the call to mb() with a call to atomic_thread_fence_seq_cst(), which is already used in virtio.c Reviewed by: pmooney_pfmooney.com, bryanv MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D20581 Modified: head/usr.sbin/bhyve/pci_virtio_console.c head/usr.sbin/bhyve/pci_virtio_net.c head/usr.sbin/bhyve/pci_virtio_scsi.c head/usr.sbin/bhyve/virtio.c head/usr.sbin/bhyve/virtio.h Modified: head/usr.sbin/bhyve/pci_virtio_console.c ============================================================================== --- head/usr.sbin/bhyve/pci_virtio_console.c Tue Jun 11 15:36:36 2019 (r348928) +++ head/usr.sbin/bhyve/pci_virtio_console.c Tue Jun 11 15:52:41 2019 (r348929) @@ -607,7 +607,7 @@ pci_vtcon_notify_rx(void *vsc, struct vqueue_info *vq) if (!port->vsp_rx_ready) { port->vsp_rx_ready = 1; - vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; + vq_kick_disable(vq); } } Modified: head/usr.sbin/bhyve/pci_virtio_net.c ============================================================================== --- head/usr.sbin/bhyve/pci_virtio_net.c Tue Jun 11 15:36:36 2019 (r348928) +++ head/usr.sbin/bhyve/pci_virtio_net.c Tue Jun 11 15:52:41 2019 (r348929) @@ -39,7 +39,6 @@ __FBSDID("$FreeBSD$"); #include <sys/select.h> #include <sys/uio.h> #include <sys/ioctl.h> -#include <machine/atomic.h> #include <net/ethernet.h> #ifndef NETMAP_WITH_LIBS #define NETMAP_WITH_LIBS @@ -585,7 +584,7 @@ pci_vtnet_ping_rxq(void *vsc, struct vqueue_info *vq) */ if (sc->vsc_rx_ready == 0) { sc->vsc_rx_ready = 1; - vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; + vq_kick_disable(vq); } } @@ -631,7 +630,7 @@ pci_vtnet_ping_txq(void *vsc, struct vqueue_info *vq) /* Signal the tx thread for processing */ pthread_mutex_lock(&sc->tx_mtx); - vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; + vq_kick_disable(vq); if (sc->tx_in_progress == 0) pthread_cond_signal(&sc->tx_cond); pthread_mutex_unlock(&sc->tx_mtx); @@ -660,8 +659,7 @@ pci_vtnet_tx_thread(void *param) for (;;) { /* note - tx mutex is locked here */ while (sc->resetting || !vq_has_descs(vq)) { - vq->vq_used->vu_flags &= ~VRING_USED_F_NO_NOTIFY; - mb(); + vq_kick_enable(vq); if (!sc->resetting && vq_has_descs(vq)) break; @@ -669,7 +667,7 @@ pci_vtnet_tx_thread(void *param) error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx); assert(error == 0); } - vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; + vq_kick_disable(vq); sc->tx_in_progress = 1; pthread_mutex_unlock(&sc->tx_mtx); Modified: head/usr.sbin/bhyve/pci_virtio_scsi.c ============================================================================== --- head/usr.sbin/bhyve/pci_virtio_scsi.c Tue Jun 11 15:36:36 2019 (r348928) +++ head/usr.sbin/bhyve/pci_virtio_scsi.c Tue Jun 11 15:52:41 2019 (r348929) @@ -581,7 +581,7 @@ static void pci_vtscsi_eventq_notify(void *vsc, struct vqueue_info *vq) { - vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; + vq_kick_disable(vq); } static void Modified: head/usr.sbin/bhyve/virtio.c ============================================================================== --- head/usr.sbin/bhyve/virtio.c Tue Jun 11 15:36:36 2019 (r348928) +++ head/usr.sbin/bhyve/virtio.c Tue Jun 11 15:52:41 2019 (r348929) @@ -428,7 +428,8 @@ vq_relchain(struct vqueue_info *vq, uint16_t idx, uint /* * Ensure the used descriptor is visible before updating the index. - * This is necessary on ISAs with memory ordering less strict than x86. + * This is necessary on ISAs with memory ordering less strict than x86 + * (and even on x86 to act as a compiler barrier). */ atomic_thread_fence_rel(); vuh->vu_idx = uidx; Modified: head/usr.sbin/bhyve/virtio.h ============================================================================== --- head/usr.sbin/bhyve/virtio.h Tue Jun 11 15:36:36 2019 (r348928) +++ head/usr.sbin/bhyve/virtio.h Tue Jun 11 15:52:41 2019 (r348929) @@ -31,6 +31,8 @@ #ifndef _VIRTIO_H_ #define _VIRTIO_H_ +#include <machine/atomic.h> + /* * These are derived from several virtio specifications. * @@ -445,6 +447,26 @@ vq_interrupt(struct virtio_softc *vs, struct vqueue_in pci_lintr_assert(vs->vs_pi); VS_UNLOCK(vs); } +} + +static inline void +vq_kick_enable(struct vqueue_info *vq) +{ + + vq->vq_used->vu_flags &= ~VRING_USED_F_NO_NOTIFY; + /* + * Full memory barrier to make sure the store to vu_flags + * happens before the load from va_idx, which results from + * a subsequent call to vq_has_descs(). + */ + atomic_thread_fence_seq_cst(); +} + +static inline void +vq_kick_disable(struct vqueue_info *vq) +{ + + vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; } struct iovec; _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
