From 55289fb036481396466d7825fa01d829c891108c Mon Sep 17 00:00:00 2001 From: Pavel Butsykin Date: Tue, 19 Sep 2017 15:07:33 +0300 Subject: virtio-serial: add enable_backend callback We should guarantee that RAM will not be modified while VM has a stopped state, otherwise it can lead to negative consequences during post-copy migration. In RUN_STATE_FINISH_MIGRATE step, it's expected that RAM on source side will not be modified as this could lead to non-consistent vm state on the destination side. Also RAM access during postcopy-ram migration with enabled release-ram capability can lead to sad consequences. Let's add enable_backend() callback to avoid undesirable virtioqueue changes in the guest memory. Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com> Message-Id: <20170919120733.22020-1-pbutsykin@virtuozzo.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- hw/char/virtio-serial-bus.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'hw/char/virtio-serial-bus.c') diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index 17a1bb008a..9470bd7be7 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -637,6 +637,13 @@ static void set_status(VirtIODevice *vdev, uint8_t status) if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) { guest_reset(vser); } + + QTAILQ_FOREACH(port, &vser->ports, next) { + VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port); + if (vsc->enable_backend) { + vsc->enable_backend(port, vdev->vm_running); + } + } } static void vser_reset(VirtIODevice *vdev) -- cgit v1.2.3-55-g7522