From acd6d327ae856e72f084949fd71314237a4b9b8b Mon Sep 17 00:00:00 2001 Message-Id: From: Juan Quintela Date: Wed, 7 Jan 2015 16:45:05 -0600 Subject: [CHANGE 01/10] net: Forbid dealing with packets when VM is not running To: rhvirt-patches@redhat.com, jen@redhat.com RH-Author: Juan Quintela Message-id: <1420649114-17435-2-git-send-email-quintela@redhat.com> Patchwork-id: 63158 O-Subject: [PATCH qemu-kvm RHEL6.7 01/10] net: Forbid dealing with packets when VM is not running Bugzilla: 970103 RH-Acked-by: Laszlo Ersek RH-Acked-by: Paolo Bonzini RH-Acked-by: Dr. David Alan Gilbert (git) From: zhanghailiang For all NICs(except virtio-net) emulated by qemu, Such as e1000, rtl8139, pcnet and ne2k_pci, Qemu can still receive packets when VM is not running. If this happened in *migration's* last PAUSE VM stage, but before the end of the migration, the new receiving packets will possibly dirty parts of RAM which has been cached in *iovec*(will be sent asynchronously) and dirty parts of new RAM which will be missed. This will lead serious network fault in VM. To avoid this, we forbid receiving packets in generic net code when VM is not running. Bug reproduction steps: (1) Start a VM which configured at least one NIC (2) In VM, open several Terminal and do *Ping IP -i 0.1* (3) Migrate the VM repeatedly between two Hosts And the *PING* command in VM will very likely fail with message: 'Destination HOST Unreachable', the NIC in VM will stay unavailable unless you run 'service network restart' Signed-off-by: zhanghailiang Reviewed-by: Jason Wang Reviewed-by: Juan Quintela Reviewed-by: Michael S. Tsirkin Signed-off-by: Stefan Hajnoczi (cherry picked from commit e1d64c084b2cc7e907b4e64026d8c8dba59116f8) Signed-off-by: Jeff E. Nelson Conflicts: net/net.c We need to change to ./net.c (file moved) We don't need the include file on RHEL6. Signed-off-by: Juan Quintela --- net.c | 6 ++++++ 1 file changed, 6 insertions(+) Signed-off-by: Jeff E. Nelson --- net.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net.c b/net.c index 4ca648a..ef87f55 100644 --- a/net.c +++ b/net.c @@ -395,6 +395,12 @@ int qemu_can_send_packet(VLANClientState *sender) VLANState *vlan = sender->vlan; VLANClientState *vc; + int vm_running = runstate_is_running(); + + if (!vm_running) { + return 0; + } + if (sender->peer) { if (sender->peer->receive_disabled) { return 0; -- 2.1.0