| Message ID | ef9d322b3faa0792f27bd512b8867c2b993ecda1.1405418492.git.amit.shah@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Jul 15, 2014 at 03:31:32PM +0530, Amit Shah wrote: > We keep port 0 reserved for compat with older guests, where only > virtio-console was expected. Even if a system is started without a > virtio-console port, port #0 is kept aside. However, after a > virtconsole port is unplugged, port id 0 became available, and the next > hotplug of a virtserialport caused failure due to it not being a console > port. > > Steps to reproduce: > > $ ./x86_64-softmmu/qemu-system-x86_64 -m 512 -cpu host -enable-kvm -device virtio-serial-pci -monitor stdio -vnc :1 > QEMU 2.0.91 monitor - type 'help' for more information > (qemu) device_add virtconsole,id=p1 > (qemu) device_del p1 > (qemu) device_add virtserialport,id=p1 > Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility. > Device 'virtserialport' could not be initialized > (qemu) quit > > Reported-by: dengmin <mdeng@redhat.com> > Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Amos Kong <akong@redhat.com> > --- > v2: > - move calculation of 'i' inside if stmt too (Paolo) > - re-word comment > > v3: > - fix typo in comment > --- > hw/char/virtio-serial-bus.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c > index 07bebc0..23123b7 100644 > --- a/hw/char/virtio-serial-bus.c > +++ b/hw/char/virtio-serial-bus.c > @@ -797,10 +797,18 @@ static void add_port(VirtIOSerial *vser, uint32_t port_id) > static void remove_port(VirtIOSerial *vser, uint32_t port_id) > { > VirtIOSerialPort *port; > - unsigned int i; > > - i = port_id / 32; > - vser->ports_map[i] &= ~(1U << (port_id % 32)); > + /* > + * Don't mark port 0 removed -- we explicitly reserve it for > + * backward compat with older guests, ensure a virtconsole device > + * unplug retains the reservation. > + */ > + if (port_id) { > + unsigned int i; > + > + i = port_id / 32; > + vser->ports_map[i] &= ~(1U << (port_id % 32)); > + } > > port = find_port_by_id(vser, port_id); > /* > -- > 1.9.3
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index 07bebc0..23123b7 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -797,10 +797,18 @@ static void add_port(VirtIOSerial *vser, uint32_t port_id) static void remove_port(VirtIOSerial *vser, uint32_t port_id) { VirtIOSerialPort *port; - unsigned int i; - i = port_id / 32; - vser->ports_map[i] &= ~(1U << (port_id % 32)); + /* + * Don't mark port 0 removed -- we explicitly reserve it for + * backward compat with older guests, ensure a virtconsole device + * unplug retains the reservation. + */ + if (port_id) { + unsigned int i; + + i = port_id / 32; + vser->ports_map[i] &= ~(1U << (port_id % 32)); + } port = find_port_by_id(vser, port_id); /*
We keep port 0 reserved for compat with older guests, where only virtio-console was expected. Even if a system is started without a virtio-console port, port #0 is kept aside. However, after a virtconsole port is unplugged, port id 0 became available, and the next hotplug of a virtserialport caused failure due to it not being a console port. Steps to reproduce: $ ./x86_64-softmmu/qemu-system-x86_64 -m 512 -cpu host -enable-kvm -device virtio-serial-pci -monitor stdio -vnc :1 QEMU 2.0.91 monitor - type 'help' for more information (qemu) device_add virtconsole,id=p1 (qemu) device_del p1 (qemu) device_add virtserialport,id=p1 Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility. Device 'virtserialport' could not be initialized (qemu) quit Reported-by: dengmin <mdeng@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> --- v2: - move calculation of 'i' inside if stmt too (Paolo) - re-word comment v3: - fix typo in comment --- hw/char/virtio-serial-bus.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)