Re: [Xen-devel] How to switch VGA passthrough live

[Jean Guyader <jean.guyader@xxxxxxxxxxxxx>]

Here is a patch for xen-4 (ioemu).

Jean

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---

diff --git a/xen-vl-extra.c b/xen-vl-extra.c
index 206ac65..bafc5a4 100644
--- a/xen-vl-extra.c
+++ b/xen-vl-extra.c
@@ -111,13 +111,18 @@ void do_pci_del(char *devname)
 
     devfn = bdf_to_devfn(devname);
 
-    if (devfn < 0)
+    if (devfn < 0 && devfn == 0x10)
         fprintf(logfile, "Device \"%s\" is not used by a hotplug device.\n",
                 devname_cpy);
     else
         acpi_php_del(devfn);
 
     free(devname_cpy);
+    if (devfn == 0x10)
+    {
+        power_off_php_devfn(devfn);
+        xenstore_record_dm_state("pci-removed");
+    }
 }
 
 void do_pci_add(char *devname)

On Mon, Jun 07, 2010 at 02:54:00AM +0100, ääè wrote:
> 
> It seems a complex work. Could you give the old patch, and I try to port it 
> on Xen4.0.
> 
> 2010/6/5 Jean Guyader 
> <jean.guyader@xxxxxxxxxxxxx<mailto:jean.guyader@xxxxxxxxxxxxx>>
> 
> Hi,
> 
> I tried that in the past and is was working fine but you have to put the
> guest into S3 (acpi suspend to RAM) first, then we don't have to wait for
> any ACPI hotplug ack (you could remove some code in qemu for that).
> 
> Jean
> 
> On Fri, Jun 04, 2010 at 10:29:43AM +0100, ääè wrote:
> > Hi,
> >
> > I want to switch video card live between two HVMs. My simplest idea is that 
> > when the HVM has the permission to access passthrough video card, and 
> > another HVM will be paused. If switch from A to B, execute commands :
> >
> > xm pause A ;
> > xm pci-detach A  00:00:02.0 ;
> > xm pci-attach B 00:00:02.0 ;
> > xm unpause B.
> >
> > I have a try, but failed. The pseudo-code is as below. Can you give me some 
> > ideas? Any suggestions will be thankful.
> >
> > Execute âxm pci-detach Domain 00:00:02.0â:
> >
> > 1.       Raise sci interrupt to unplug the device. If OSPM doesnât handle 
> > the unplug process, and then invoke acpi_php_writeb to power off the device.
> >
> > 2.       Modify power_off_php_devfn function:
> > int power_off_php_devfn(int php_devfn)
> > {
> >                     If(php_devfn == 0x10)  // Intel integrated graphics
> >                     {
> >                              p = & dpci_infos.php_devs[php_devfn];
> >
> >        // save the two-tuples : (php_dev, domid)
> >        save_php_device_by_domid(p,domid);
> >
> >        // hide the device from bus and dpci_infos
> >                              pci_hide_device(& p->pt_dev->dev);
> >                              memset(p,0x00,sizeof(struct php_dev));
> >
> >                              return 0;
> >                     }
> >
> >     return unregister_real_device(php_devfn);
> >
> > }
> >
> > Execute âxm pci-attach Domain 00:00:02.0â:
> >
> > 1.       Modify power_on_php_devfn function:
> >
> > int power_off_php_devfn(int devfn)
> >
> > {
> >
> >            â.
> >
> >            while(devfn == 0x10) // Intel integrated graphics
> >
> >            {
> >
> >                     if( ! get_php_device_by_domid(p,domid) ) // get saved 
> > php_dev struct
> >
> >                              break;                                     // 
> > cannot get , create new one
> >
> >
> >
> >                     //restore the php device to bus and dpci_infos
> >
> >                     restore_php_device(p,devfn);         // restore 
> > dpci_infos.php_devs[devfn]
> >
> >                     dpci_infos->e_bus->devices[devfn] = p-> pt_dev->dev;
> >
> >
> >
> >                     return 0;
> >
> >            }
> >
> >
> >
> >            if (!dpci_infos.pci_access)
> >
> >            {â}
> >
> >            pt_dev = register_real_device(..);
> >
> >   return 0;
> >
> > }
> >
> > This plan hides the VGA device from HVM and never destroys it. Both mmio 
> > and pio maps are reserved. When finishing âxm unpause Bâ, it seems working 
> > well observed by Dom0 serial port login. But the screen is black and cannot 
> > receive any signal. I am confusing. Video BIOS should be reloaded? Or need 
> > raise some interrupt to flush screen?
> >
> >
> > Thanks & Regards,
> > Yujiageng
> 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx<mailto:Xen-devel@xxxxxxxxxxxxxxxxxxx>
> > http://lists.xensource.com/xen-devel
> 
> 

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