From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35134) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f4Q6e-0005gg-0d for qemu-devel@nongnu.org; Fri, 06 Apr 2018 08:04:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f4Q6Z-0001YI-39 for qemu-devel@nongnu.org; Fri, 06 Apr 2018 08:04:36 -0400 Received: from mail-co1nam03on0081.outbound.protection.outlook.com ([104.47.40.81]:3680 helo=NAM03-CO1-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f4Q6Y-0001XM-Ba for qemu-devel@nongnu.org; Fri, 06 Apr 2018 08:04:31 -0400 From: Brijesh Singh Date: Fri, 6 Apr 2018 07:03:56 -0500 Message-Id: <20180406120356.24757-1-brijesh.singh@amd.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH for-2.12] tap: set vhostfd passed from qemu cli to non-blocking List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Thomas.Lendacky@amd.com, Brijesh Singh , "Michael S . Tsirkin" , Jason Wang 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 Cc: Jason Wang Signed-off-by: Brijesh Singh --- 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