[Spice-devel] Fail to create a printing channel
Charles.Tsai-蔡清海-研究發展部
charles.tsai at cloudena.com
Fri Mar 23 02:55:21 PDT 2012
Alon,
Thank you for information.
In order isolate the issue, I simply just ran the following script to create the printing channel.
Initially, I disable the Virio serial adapter. When I enable the Virtio serial adapter, the Windows is totally locked up.
I am going to debug the Windows virtio serial driver to see if I can find something there or not.
To my understanding, the creation of vdagent and vdprint should be similar inside the Qemu. I do not know why the system is locked after I enable the vireo serial PCI adapter.
====================
ARGS="-localtime -spice port=5900,disable-ticketing \
-drive file=/opt/virt/user/Win7_64.cow \
-vga qxl \
-device virtio-serial-pci \
-usbdevice tablet -smp 1,cores=2 -m 2048 -enable-kvm \
-net nic -net user \
-chardev spicevmc,id=vdprint,name=vdprint \
-device virtserialport,chardev=vdprint,name=com.redhat.print.0"
-----Original Message-----
From: Alon Levy [mailto:alevy at redhat.com]
Sent: Friday, March 23, 2012 5:03 PM
To: Charles.Tsai-蔡清海-研究發展部
Cc: spice-devel at lists.freedesktop.org
Subject: Re: Fail to create a printing channel
On Fri, Mar 23, 2012 at 05:08:34AM +0000, Charles.Tsai-蔡清海-研究發展部 wrote:
> Alon,
>
> In Windows, driver name is provided by the device driver. In this case , "com.redhat.print.0" is the device visible to application.
> Because device "com.redhat.print.0" is created by the Qemu which is in
> Linux, how the Linux passes the driver information to Windows So that Windows application can open it.
>
> When I observed the trace of the spice server, I found vdagent seems to be created after Windows viritio driver is loaded.
> In other words, the creation of vdagent device seems to be triggered by the Windows OS other than from the qemu command line.
> By the same token, "vdprint" should be created after "com.redhat.print.0" is loaded by Windows OS.
>
> So far, I am still looking at the link between "vdprint" and "com.redhat.print.0". It looks like the virioserial driver must be modified.
> Otherwise, how the Windows application can see such a device?
For vdagent, what you have is:
qemu virtio serial bus pci device
qemu virtio serial port named "com.redhat.spice.0"
guest virtio serial pci driver
guest vdservice.exe
guest vdagent.exe
Guest startup:
loads virtio serial pci driver.
-> creates a device file for named "com.redhat.spice.0"
starts vdservice.exe
-> opens the file "com.redhat.spice.0"
starts vdagent.exe
So for the printer driver I imagined you would have a printer driver, vdprint.sys, that would do the same as vdservice.exe, i.e.
Setup:
virtio serial bus
virtio serial port "com.redhat.print.0"
guest virtio serial pci driver
guest vdprinter driver (needs to make sure this loads after virtio)
Startup:
load virtio serial pci driver
load vdprinter driver
Alon
>
>
> -----Original Message-----
> From: Alon Levy [mailto:alevy at redhat.com]
> Sent: Thursday, March 22, 2012 10:22 PM
> To: Charles.Tsai-蔡清海-研究發展部
> Cc: spice-devel at lists.freedesktop.org
> Subject: Re: Fail to create a printing channel
>
> On Thu, Mar 22, 2012 at 09:55:45PM +0800, Charles.Tsai-蔡清海-研究發展部 wrote:
> > Alon,
> >
> > I did all of what you mentioned before. Nothing is missed in my checklist.
> > Function "spice_server_char_device_add_interface" in fact is not called at all.
> > Qemu somehow is blocked somewhere. For now, I still do not know the root cause.
> >
>
> OK. So nothing comes to mind. Where is it stuck?
>
> >
> > -----Original Message-----
> > From: Alon Levy [mailto:alevy at redhat.com]
> > Sent: Thursday, March 22, 2012 9:47 PM
> > To: Charles.Tsai-蔡清海-研究發展部
> > Cc: spice-devel at lists.freedesktop.org
> > Subject: Re: Fail to create a printing channel
> >
> > On Thu, Mar 22, 2012 at 07:34:38PM +0800, Charles.Tsai-蔡清海-研究發展部 wrote:
> > > Alon,
> >
> > Or anyone else on the list..
> >
> > >
> > > I am running the following script to create the printing channel based on the virtio device framework.
> > > When the VM is launched, it seems to block somewhere in Qemu.
> > >
> > > If I remove the following two lines, the VM can be launched without any problem.
> > > The following two lines basically are used to create the printing channel between the host and guest.
> > >
> > > -chardev spicevmc,id=vdprint,name=vdprint \
> > > -device virtserialport,chardev=vdprint,name=com.redhat.print.0"
> > >
> > > Can you give me some hits why Qemu does not call spice server to create the printing channel? Is there any function in Qemu I need to change so as to create additional channel within the Virtio device?
> > >
> > > Let me know if I made anything wrong with my Qemu's command options. Thanks.
> >
> > How it works right now, and it's probably not how we want it to be, is that there is a function qemu calls to get the allowed list of names by spice-server. That function is implemented by spice-server, so you would need to add the "vdprint" string to it.
> >
> > diff --git a/server/reds.c b/server/reds.c index c54d30c..bb75624
> > 100644
> > --- a/server/reds.c
> > +++ b/server/reds.c
> > @@ -3364,6 +3364,7 @@ SPICE_GNUC_VISIBLE void
> > spice_server_char_device_wakeup(SpiceCharDeviceInstance*
> > #define SUBTYPE_VDAGENT "vdagent"
> > #define SUBTYPE_SMARTCARD "smartcard"
> > #define SUBTYPE_USBREDIR "usbredir"
> > +#define SUBTYPE_PRINTER "printer"
> >
> > const char *spice_server_char_device_recognized_subtypes_list[] = {
> > SUBTYPE_VDAGENT,
> > @@ -3371,6 +3372,7 @@ const char *spice_server_char_device_recognized_subtypes_list[] = {
> > SUBTYPE_SMARTCARD,
> > #endif
> > SUBTYPE_USBREDIR,
> > + SUBTYPE_PRINTER,
> > NULL,
> > };
> >
> > Then you need to tell spice what to do when spice_server_char_device_add_interface is called with this subtype (subtype == 'name' parameter to the chardev. Another thing that should be changed).
> >
> > You could basically just use another spicevmc_device_connect call.
> > You will need to add the channel to the spice.proto (again, this
> > should be changed so adding generic channels doesn't require this -
> > something like having a generic channel subtype, and having a
> > message that tells the client which channel this is - will be a
> > little ugly since getting a channel list won't be enough for the
> > client to know what channels are available, but it's not too bad -
> > anyway off topic)
> >
> > For now you can just change the spice-protocol/spice/enums.h file directly instead of recreating it:
> >
> > U x86_64 garlic:spice-protocol alon ((1a3b563...))$ git diff diff
> > --git a/spice/enums.h b/spice/enums.h index d2dbfd0..9f54ac0 100644
> > --- a/spice/enums.h
> > +++ b/spice/enums.h
> > @@ -330,6 +330,7 @@ enum {
> > SPICE_CHANNEL_TUNNEL,
> > SPICE_CHANNEL_SMARTCARD,
> > SPICE_CHANNEL_USBREDIR,
> > + SPICE_CHANNEL_PRINTER,
> >
> > SPICE_END_CHANNEL
> > };
> >
> > @@ -3401,9 +3403,13 @@ static int spice_server_char_device_add_interface(SpiceServer *s,
> > }
> > }
> > #endif
> > + /* all other channels use the generic spicevmc channel */
> > else if (strcmp(char_device->subtype, SUBTYPE_USBREDIR) == 0) {
> > spicevmc_device_connect(char_device, SPICE_CHANNEL_USBREDIR);
> > }
> > + else if (strcmp(char_device->subtype, SUBTYPE_PRINTER) == 0) {
> > + spicevmc_device_connect(char_device, SPICE_CHANNEL_PRINTER);
> > + }
> > return 0;
> > }
> >
> > Hope you can understand my not very collected response.
> >
> > Bonus points for sending patches to fix the raised issues, or starting a discussion on how to exactly.
> >
> > Alon
> >
> > > ==================================
> > >
> > > #!/bin/sh
> > >
> > > ARGS="-localtime -spice port=5900,disable-ticketing \ -drive
> > > file=/opt/virt/user/Win7_64.cow \ -vga qxl \ -device
> > > virtio-serial-pci,multifunction=on \ -chardev
> > > spicevmc,id=vdagent,id=vdagent,name=vdagent \ -device
> > > virtserialport,chardev=vdagent,name=com.redhat.spice.0 \
> > > -usbdevice tablet -smp 1,cores=2 -m 2048 -enable-kvm -net nic -net
> > > user \ -chardev spicevmc,id=vdprint,name=vdprint \ -device
> > > virtserialport,chardev=vdprint,name=com.redhat.print.0"
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