| Message ID | 20180406120356.24757-1-brijesh.singh@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/06/2018 07:03 AM, Brijesh Singh wrote: > 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: Michael S. Tsirkin <mst@redhat.com> > Cc: Jason Wang <jasowang@redhat.com> > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > net/tap.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/tap.c b/net/tap.c > index 2b3a36f9b50d..8c026fbf95cd 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -693,6 +693,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer, > } > return; > } > + fcntl(vhostfd, F_SETFL, O_NONBLOCK); Please use qemu_set_nonblock() instead.
On 04/06/2018 10:44 AM, Eric Blake wrote: > On 04/06/2018 07:03 AM, Brijesh Singh wrote: >> 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: Michael S. Tsirkin <mst@redhat.com> >> Cc: Jason Wang <jasowang@redhat.com> >> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> >> --- >> net/tap.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/net/tap.c b/net/tap.c >> index 2b3a36f9b50d..8c026fbf95cd 100644 >> --- a/net/tap.c >> +++ b/net/tap.c >> @@ -693,6 +693,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer, >> } >> return; >> } >> + fcntl(vhostfd, F_SETFL, O_NONBLOCK); > > Please use qemu_set_nonblock() instead. > Sure will do.
On Fri, Apr 06, 2018 at 07:03:56AM -0500, Brijesh Singh wrote: > 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: Michael S. Tsirkin <mst@redhat.com> > Cc: Jason Wang <jasowang@redhat.com> > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > --- > net/tap.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/tap.c b/net/tap.c > index 2b3a36f9b50d..8c026fbf95cd 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -693,6 +693,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer, > } > return; > } > + fcntl(vhostfd, F_SETFL, O_NONBLOCK); > } else { > vhostfd = open("/dev/vhost-net", O_RDWR); > if (vhostfd < 0) { > -- > 2.14.3
diff --git a/net/tap.c b/net/tap.c index 2b3a36f9b50d..8c026fbf95cd 100644 --- a/net/tap.c +++ b/net/tap.c @@ -693,6 +693,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer, } return; } + fcntl(vhostfd, F_SETFL, O_NONBLOCK); } else { vhostfd = open("/dev/vhost-net", O_RDWR); if (vhostfd < 0) {
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: Michael S. Tsirkin <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> --- net/tap.c | 1 + 1 file changed, 1 insertion(+)