Patchwork [5/7] virtio-serial: Don't clear ->have_data() pointer after unplug

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Submitter Amit Shah
Date March 21, 2011, 1:09 p.m.
Message ID <fee063c07f20b442ef4bedef834ab0a3bf55b562.1300712809.git.amit.shah@redhat.com>
Download mbox | patch
Permalink /patch/87777/
State New
Headers show

Comments

Amit Shah - March 21, 2011, 1:09 p.m.
After a port unplug operation, the port->info->have_data() pointer was
set to NULL.  The problem is, the ->info struct is shared by all ports,
effectively disabling writes to other ports.

Reported-by: juzhang <juzhang@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-console.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
Juan Quintela - March 23, 2011, 1:33 p.m.
Amit Shah <amit.shah@redhat.com> wrote:
> After a port unplug operation, the port->info->have_data() pointer was
> set to NULL.  The problem is, the ->info struct is shared by all ports,
> effectively disabling writes to other ports.
>
> Reported-by: juzhang <juzhang@redhat.com>
> Signed-off-by: Amit Shah <amit.shah@redhat.com>
> ---
>  hw/virtio-console.c |    1 -
>  1 files changed, 0 insertions(+), 1 deletions(-)
>
> diff --git a/hw/virtio-console.c b/hw/virtio-console.c
> index 4440784..be59558 100644
> --- a/hw/virtio-console.c
> +++ b/hw/virtio-console.c
> @@ -82,7 +82,6 @@ static int virtconsole_exitfn(VirtIOSerialPort *port)
>      VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
>  
>      if (vcon->chr) {
> -        port->info->have_data = NULL;
>          qemu_chr_close(vcon->chr);
>      }

Discussed with Amit over irc, I think that we are missing setup of
have_data for non console devices, but that is a different bug that the
one being fixed here.

Later, Juan.
Amit Shah - March 23, 2011, 1:39 p.m.
On (Wed) 23 Mar 2011 [14:33:25], Juan Quintela wrote:
> Amit Shah <amit.shah@redhat.com> wrote:
> > After a port unplug operation, the port->info->have_data() pointer was
> > set to NULL.  The problem is, the ->info struct is shared by all ports,
> > effectively disabling writes to other ports.
> >
> > Reported-by: juzhang <juzhang@redhat.com>
> > Signed-off-by: Amit Shah <amit.shah@redhat.com>
> > ---
> >  hw/virtio-console.c |    1 -
> >  1 files changed, 0 insertions(+), 1 deletions(-)
> >
> > diff --git a/hw/virtio-console.c b/hw/virtio-console.c
> > index 4440784..be59558 100644
> > --- a/hw/virtio-console.c
> > +++ b/hw/virtio-console.c
> > @@ -82,7 +82,6 @@ static int virtconsole_exitfn(VirtIOSerialPort *port)
> >      VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
> >  
> >      if (vcon->chr) {
> > -        port->info->have_data = NULL;
> >          qemu_chr_close(vcon->chr);
> >      }
> 
> Discussed with Amit over irc, I think that we are missing setup of
> have_data for non console devices, but that is a different bug that the
> one being fixed here.

Actually other virtio_serial devices will provide their own have_data,
like spice did earlier (now it's a chardev, so it uses this code
path).

I think the bug is that we should set have_data regardless of a chardev
backend and call qemu_chr_write() in have_data only if a chardev
exists.

		Amit

Patch

diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index 4440784..be59558 100644
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -82,7 +82,6 @@  static int virtconsole_exitfn(VirtIOSerialPort *port)
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 
     if (vcon->chr) {
-        port->info->have_data = NULL;
         qemu_chr_close(vcon->chr);
     }