From: Brijesh Singh <brijesh.si...@amd.com> A guest boot hangs while probing the network interface when iommu_platform=on is used.
The following qemu cli hangs without this patch: # $QEMU \ -netdev tap,fd=3,id=hostnet0,vhost=on,vhostfd=4 3<>/dev/tap67 4<>/dev/host-net \ -device virtio-net-pci,netdev=hostnet0,id=net0,iommu_platform=on,disable-legacy=on \ ... Commit: c471ad0e9bd46 (vhost_net: device IOTLB support) took care of setting vhostfd to non-blocking when QEMU opens /dev/host-net but if the fd is passed from qemu cli then we need to ensure that fd is set to non-blocking. Fixes: c471ad0e9bd46 ("vhost_net: device IOTLB support") Cc: qemu-sta...@nongnu.org Cc: Michael S. Tsirkin <m...@redhat.com> Cc: Jason Wang <jasow...@redhat.com> Signed-off-by: Brijesh Singh <brijesh.si...@amd.com> Signed-off-by: Jason Wang <jasow...@redhat.com> (cherry picked from commit d542800d1edc62f63f8a29cfa6bdd1a9536ae11c) Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com> --- net/tap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/tap.c b/net/tap.c index 979e622e60..aefd6edd1e 100644 --- a/net/tap.c +++ b/net/tap.c @@ -40,6 +40,7 @@ #include "qemu-common.h" #include "qemu/cutils.h" #include "qemu/error-report.h" +#include "qemu/sockets.h" #include "net/tap.h" @@ -689,6 +690,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer, error_propagate(errp, err); return; } + qemu_set_nonblock(vhostfd); } else { vhostfd = open("/dev/vhost-net", O_RDWR); if (vhostfd < 0) { -- 2.11.0