[PATCH 0/2] qemu:xen: implement isa bridge specific to IGD passthrough

[PATCH 0/2] qemu:xen: implement isa bridge specific to IGD passthrough

[Tiejun Chen]

This is a subset to support IGD passthrough with qemu/xen, and this should be
based on

http://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg02166.html

We will register to create isa bridge specific to IGD passthrough.

----------------------------------------------------------------
Tiejun Chen (2):
      hw:xen:xen_pt: register isa bridge specific to IGD passthrough
      xen:i386:pc_piix: create isa bridge specific to IGD passthrough

 hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
 hw/xen/xen_pt.c   | 21 +++++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

Thanks
Tiejun

[PATCH 1/2] hw:xen:xen_pt: register isa bridge specific to IGD passthrough

[Tiejun Chen]

We need this instance to passthrough some config fields of PCH.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
---
 hw/xen/xen_pt.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index c1bf357..bf72719 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -829,3 +829,24 @@ static void xen_pci_passthrough_register_types(void)
 }
 
 type_init(xen_pci_passthrough_register_types)
+
+static void xen_igd_passthrough_isa_bridge_class_init(ObjectClass *klass,
+                                                      void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->class_id = PCI_CLASS_BRIDGE_ISA;
+};
+
+static TypeInfo xen_igd_passthrough_isa_bridge_info = {
+    .name           = "xen-igd-passthrough-isa-bridge",
+    .parent         = TYPE_PCI_DEVICE,
+    .class_init     = xen_igd_passthrough_isa_bridge_class_init,
+};
+
+static void xen_igd_passthrough_isa_bridge_register_types(void)
+{
+    type_register_static(&xen_igd_passthrough_isa_bridge_info);
+}
+
+type_init(xen_igd_passthrough_isa_bridge_register_types);
-- 
1.9.1

[PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Tiejun Chen]

Currenjly this ISA bridge should be fixed at 1f.0, and pass the
real vendor/device ids as the driver expect.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
---
 hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 7710724..b131fa3 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -50,7 +50,8 @@
 #include "cpu.h"
 #include "qemu/error-report.h"
 #ifdef CONFIG_XEN
-#  include <xen/hvm/hvm_info_table.h>
+#include <xen/hvm/hvm_info_table.h>
+#include <hw/xen/xen-host-pci-device.h>
 #endif
 
 #define MAX_IDE_BUS 2
@@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState *machine)
     }
 }
 
+static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
+{
+    struct PCIDevice *dev;
+    XenHostPCIDevice hdev;
+    int r = 0;
+
+    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.
+     */
+    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
+                            "xen-igd-passthrough-isa-bridge");
+    if (dev) {
+        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f, 0), 0);
+        if (!r) {
+            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
+            pci_config_set_device_id(dev->config, hdev.device_id);
+        } else
+            fprintf(stderr, "xen set xen-igd-passthrough-isa-bridge failed\n");
+    }
+}
+
 static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
 {
     PCIBus *bus;
@@ -472,6 +493,7 @@ static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
     bus = pci_find_primary_bus();
     if (bus != NULL) {
         pci_create_simple(bus, -1, "xen-platform");
+        xen_igd_passthrough_isa_bridge_create(bus);
     }
 }
 #endif
-- 
1.9.1

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Konrad Rzeszutek Wilk]

On Thu, Aug 21, 2014 at 09:28:28AM +0800, Tiejun Chen wrote:
> Currenjly this ISA bridge should be fixed at 1f.0, and pass the

Currently

> real vendor/device ids as the driver expect.

Could you add a bit more description to this patch please? Explain
the rationale, etc.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> ---
>  hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 7710724..b131fa3 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -50,7 +50,8 @@
>  #include "cpu.h"
>  #include "qemu/error-report.h"
>  #ifdef CONFIG_XEN
> -#  include <xen/hvm/hvm_info_table.h>
> +#include <xen/hvm/hvm_info_table.h>
> +#include <hw/xen/xen-host-pci-device.h>
>  #endif
>  
>  #define MAX_IDE_BUS 2
> @@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState *machine)
>      }
>  }
>  
> +static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
> +{
> +    struct PCIDevice *dev;
> +    XenHostPCIDevice hdev;
> +    int r = 0;
> +
> +    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.

should

However I would remove the comment as it does not add anything extra
to the function. It is pretty clear what it is doing.

What would help is if you said:

Must be fixed at 1f.0 because .. bla blah

> +     */
> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
> +                            "xen-igd-passthrough-isa-bridge");
> +    if (dev) {
> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f, 0), 0);
> +        if (!r) {
> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
> +            pci_config_set_device_id(dev->config, hdev.device_id);
> +        } else
> +            fprintf(stderr, "xen set xen-igd-passthrough-isa-bridge failed\n");
> +    }
> +}
> +
>  static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
>  {
>      PCIBus *bus;
> @@ -472,6 +493,7 @@ static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
>      bus = pci_find_primary_bus();
>      if (bus != NULL) {
>          pci_create_simple(bus, -1, "xen-platform");
> +        xen_igd_passthrough_isa_bridge_create(bus);
>      }
>  }
>  #endif
> -- 
> 1.9.1
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]

On 2014/8/22 0:16, Konrad Rzeszutek Wilk wrote:
> On Thu, Aug 21, 2014 at 09:28:28AM +0800, Tiejun Chen wrote:
>> Currenjly this ISA bridge should be fixed at 1f.0, and pass the
>
> Currently

Fixed.

>
>> real vendor/device ids as the driver expect.
>
> Could you add a bit more description to this patch please? Explain
> the rationale, etc.

So rephrase as follows:

xen:i386:pc_piix: create isa bridge specific to IGD passthrough

Currently IGD drivers always need to access PCH by 1f.0, and
identify PCH type with its own real vendor/device ids. This type
value help driver initialize correctly.

>>
>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>> ---
>>   hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
>>   1 file changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>> index 7710724..b131fa3 100644
>> --- a/hw/i386/pc_piix.c
>> +++ b/hw/i386/pc_piix.c
>> @@ -50,7 +50,8 @@
>>   #include "cpu.h"
>>   #include "qemu/error-report.h"
>>   #ifdef CONFIG_XEN
>> -#  include <xen/hvm/hvm_info_table.h>
>> +#include <xen/hvm/hvm_info_table.h>
>> +#include <hw/xen/xen-host-pci-device.h>
>>   #endif
>>
>>   #define MAX_IDE_BUS 2
>> @@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState *machine)
>>       }
>>   }
>>
>> +static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
>> +{
>> +    struct PCIDevice *dev;
>> +    XenHostPCIDevice hdev;
>> +    int r = 0;
>> +
>> +    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.
>
> should
>
> However I would remove the comment as it does not add anything extra
> to the function. It is pretty clear what it is doing.
>
> What would help is if you said:
>
> Must be fixed at 1f.0 because .. bla blah

Like the patch description, so what about this,

     /* Currently IGD drivers always need to access PCH by 1f.0, and
      * identify PCH type with its own real vendor/device ids.
      */

Thanks
Tiejun

>
>> +     */
>> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
>> +                            "xen-igd-passthrough-isa-bridge");
>> +    if (dev) {
>> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f, 0), 0);
>> +        if (!r) {
>> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
>> +            pci_config_set_device_id(dev->config, hdev.device_id);
>> +        } else
>> +            fprintf(stderr, "xen set xen-igd-passthrough-isa-bridge failed\n");
>> +    }
>> +}
>> +
>>   static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
>>   {
>>       PCIBus *bus;
>> @@ -472,6 +493,7 @@ static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
>>       bus = pci_find_primary_bus();
>>       if (bus != NULL) {
>>           pci_create_simple(bus, -1, "xen-platform");
>> +        xen_igd_passthrough_isa_bridge_create(bus);
>>       }
>>   }
>>   #endif
>> --
>> 1.9.1
>>
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xen.org
>> http://lists.xen.org/xen-devel
>

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Michael S. Tsirkin]

On Fri, Aug 22, 2014 at 09:06:20AM +0800, Chen, Tiejun wrote:
> On 2014/8/22 0:16, Konrad Rzeszutek Wilk wrote:
> >On Thu, Aug 21, 2014 at 09:28:28AM +0800, Tiejun Chen wrote:
> >>Currenjly this ISA bridge should be fixed at 1f.0, and pass the
> >
> >Currently
> 
> Fixed.
> 
> >
> >>real vendor/device ids as the driver expect.
> >
> >Could you add a bit more description to this patch please? Explain
> >the rationale, etc.
> 
> So rephrase as follows:
> 
> xen:i386:pc_piix: create isa bridge specific to IGD passthrough
> 
> Currently IGD drivers always need to access PCH by 1f.0,

OK

> and
> identify PCH type with its own real vendor/device ids. This type
> value help driver initialize correctly.

instead: PCH vendor/device id is used to identify the card.

> >>
> >>Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> >>---
> >>  hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
> >>  1 file changed, 23 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> >>index 7710724..b131fa3 100644
> >>--- a/hw/i386/pc_piix.c
> >>+++ b/hw/i386/pc_piix.c
> >>@@ -50,7 +50,8 @@
> >>  #include "cpu.h"
> >>  #include "qemu/error-report.h"
> >>  #ifdef CONFIG_XEN
> >>-#  include <xen/hvm/hvm_info_table.h>
> >>+#include <xen/hvm/hvm_info_table.h>
> >>+#include <hw/xen/xen-host-pci-device.h>
> >>  #endif
> >>
> >>  #define MAX_IDE_BUS 2
> >>@@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState *machine)
> >>      }
> >>  }
> >>
> >>+static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
> >>+{
> >>+    struct PCIDevice *dev;
> >>+    XenHostPCIDevice hdev;
> >>+    int r = 0;
> >>+
> >>+    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.
> >
> >should
> >
> >However I would remove the comment as it does not add anything extra
> >to the function. It is pretty clear what it is doing.
> >
> >What would help is if you said:
> >
> >Must be fixed at 1f.0 because .. bla blah
> 
> Like the patch description, so what about this,
> 
>     /* Currently IGD drivers always need to access PCH by 1f.0, and
>      * identify PCH type with its own real vendor/device ids.
>      */
> 
> Thanks
> Tiejun
> 
> >
> >>+     */
> >>+    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
> >>+                            "xen-igd-passthrough-isa-bridge");
> >>+    if (dev) {
> >>+        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f, 0), 0);
> >>+        if (!r) {
> >>+            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
> >>+            pci_config_set_device_id(dev->config, hdev.device_id);

Can you, instead, implement the reverse logic, probing
the card and supplying the correct device id for PCH?

> >>+        } else
> >>+            fprintf(stderr, "xen set xen-igd-passthrough-isa-bridge failed\n");
> >>+    }
> >>+}
> >>+
> >>  static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
> >>  {
> >>      PCIBus *bus;
> >>@@ -472,6 +493,7 @@ static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
> >>      bus = pci_find_primary_bus();
> >>      if (bus != NULL) {
> >>          pci_create_simple(bus, -1, "xen-platform");
> >>+        xen_igd_passthrough_isa_bridge_create(bus);
> >>      }
> >>  }
> >>  #endif
> >>--
> >>1.9.1
> >>
> >>
> >>_______________________________________________
> >>Xen-devel mailing list
> >>Xen-devel@lists.xen.org
> >>http://lists.xen.org/xen-devel
> >

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]

On 2014/8/24 19:12, Michael S. Tsirkin wrote:
> On Fri, Aug 22, 2014 at 09:06:20AM +0800, Chen, Tiejun wrote:
>> On 2014/8/22 0:16, Konrad Rzeszutek Wilk wrote:
>>> On Thu, Aug 21, 2014 at 09:28:28AM +0800, Tiejun Chen wrote:
>>>> Currenjly this ISA bridge should be fixed at 1f.0, and pass the
>>>
>>> Currently
>>
>> Fixed.
>>
>>>
>>>> real vendor/device ids as the driver expect.
>>>
>>> Could you add a bit more description to this patch please? Explain
>>> the rationale, etc.
>>
>> So rephrase as follows:
>>
>> xen:i386:pc_piix: create isa bridge specific to IGD passthrough
>>
>> Currently IGD drivers always need to access PCH by 1f.0,
>
> OK
>
>> and
>> identify PCH type with its own real vendor/device ids. This type
>> value help driver initialize correctly.
>
> instead: PCH vendor/device id is used to identify the card.

Okay.

>
>>>>
>>>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>>>> ---
>>>>   hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
>>>>   1 file changed, 23 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>>>> index 7710724..b131fa3 100644
>>>> --- a/hw/i386/pc_piix.c
>>>> +++ b/hw/i386/pc_piix.c
>>>> @@ -50,7 +50,8 @@
>>>>   #include "cpu.h"
>>>>   #include "qemu/error-report.h"
>>>>   #ifdef CONFIG_XEN
>>>> -#  include <xen/hvm/hvm_info_table.h>
>>>> +#include <xen/hvm/hvm_info_table.h>
>>>> +#include <hw/xen/xen-host-pci-device.h>
>>>>   #endif
>>>>
>>>>   #define MAX_IDE_BUS 2
>>>> @@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState *machine)
>>>>       }
>>>>   }
>>>>
>>>> +static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
>>>> +{
>>>> +    struct PCIDevice *dev;
>>>> +    XenHostPCIDevice hdev;
>>>> +    int r = 0;
>>>> +
>>>> +    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.
>>>
>>> should
>>>
>>> However I would remove the comment as it does not add anything extra
>>> to the function. It is pretty clear what it is doing.
>>>
>>> What would help is if you said:
>>>
>>> Must be fixed at 1f.0 because .. bla blah
>>
>> Like the patch description, so what about this,
>>
>>      /* Currently IGD drivers always need to access PCH by 1f.0, and
>>       * identify PCH type with its own real vendor/device ids.
>>       */
>>
>> Thanks
>> Tiejun
>>
>>>
>>>> +     */
>>>> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
>>>> +                            "xen-igd-passthrough-isa-bridge");
>>>> +    if (dev) {
>>>> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f, 0), 0);
>>>> +        if (!r) {
>>>> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
>>>> +            pci_config_set_device_id(dev->config, hdev.device_id);
>
> Can you, instead, implement the reverse logic, probing
> the card and supplying the correct device id for PCH?
>

Here what is your so-called reverse logic as I already asked you 
previously? Do you mean I should list all PCHs with a combo illustrated 
with the vendor/device id in advance? Then look up if we can find a 
matched PCH? If yes, what is that benefit you expect in passthrough 
case? Shouldn't we pass these info to VM directly in passthrough case?

Thanks
Tiejun	

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]

On 2014/8/25 13:18, Chen, Tiejun wrote:
> On 2014/8/24 19:12, Michael S. Tsirkin wrote:
>> On Fri, Aug 22, 2014 at 09:06:20AM +0800, Chen, Tiejun wrote:
>>> On 2014/8/22 0:16, Konrad Rzeszutek Wilk wrote:
>>>> On Thu, Aug 21, 2014 at 09:28:28AM +0800, Tiejun Chen wrote:
>>>>> Currenjly this ISA bridge should be fixed at 1f.0, and pass the
>>>>
>>>> Currently
>>>
>>> Fixed.
>>>
>>>>
>>>>> real vendor/device ids as the driver expect.
>>>>
>>>> Could you add a bit more description to this patch please? Explain
>>>> the rationale, etc.
>>>
>>> So rephrase as follows:
>>>
>>> xen:i386:pc_piix: create isa bridge specific to IGD passthrough
>>>
>>> Currently IGD drivers always need to access PCH by 1f.0,
>>
>> OK
>>
>>> and
>>> identify PCH type with its own real vendor/device ids. This type
>>> value help driver initialize correctly.
>>
>> instead: PCH vendor/device id is used to identify the card.
>
> Okay.
>
>>
>>>>>
>>>>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>>>>> ---
>>>>>   hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
>>>>>   1 file changed, 23 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>>>>> index 7710724..b131fa3 100644
>>>>> --- a/hw/i386/pc_piix.c
>>>>> +++ b/hw/i386/pc_piix.c
>>>>> @@ -50,7 +50,8 @@
>>>>>   #include "cpu.h"
>>>>>   #include "qemu/error-report.h"
>>>>>   #ifdef CONFIG_XEN
>>>>> -#  include <xen/hvm/hvm_info_table.h>
>>>>> +#include <xen/hvm/hvm_info_table.h>
>>>>> +#include <hw/xen/xen-host-pci-device.h>
>>>>>   #endif
>>>>>
>>>>>   #define MAX_IDE_BUS 2
>>>>> @@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState
>>>>> *machine)
>>>>>       }
>>>>>   }
>>>>>
>>>>> +static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
>>>>> +{
>>>>> +    struct PCIDevice *dev;
>>>>> +    XenHostPCIDevice hdev;
>>>>> +    int r = 0;
>>>>> +
>>>>> +    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.
>>>>
>>>> should
>>>>
>>>> However I would remove the comment as it does not add anything extra
>>>> to the function. It is pretty clear what it is doing.
>>>>
>>>> What would help is if you said:
>>>>
>>>> Must be fixed at 1f.0 because .. bla blah
>>>
>>> Like the patch description, so what about this,
>>>
>>>      /* Currently IGD drivers always need to access PCH by 1f.0, and
>>>       * identify PCH type with its own real vendor/device ids.
>>>       */
>>>
>>> Thanks
>>> Tiejun
>>>
>>>>
>>>>> +     */
>>>>> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
>>>>> +                            "xen-igd-passthrough-isa-bridge");
>>>>> +    if (dev) {
>>>>> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f,
>>>>> 0), 0);
>>>>> +        if (!r) {
>>>>> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
>>>>> +            pci_config_set_device_id(dev->config, hdev.device_id);
>>
>> Can you, instead, implement the reverse logic, probing
>> the card and supplying the correct device id for PCH?
>>
>
> Here what is your so-called reverse logic as I already asked you
> previously? Do you mean I should list all PCHs with a combo illustrated
> with the vendor/device id in advance? Then look up if we can find a

Michael,

Could you explain this exactly? Then I can try follow-up your idea ASAP 
if this is necessary and possible.

Thanks
Tiejun

> matched PCH? If yes, what is that benefit you expect in passthrough
> case? Shouldn't we pass these info to VM directly in passthrough case?
>
> Thanks
> Tiejun
>
>
>

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]

>>>>>> +     */
>>>>>> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
>>>>>> +                            "xen-igd-passthrough-isa-bridge");
>>>>>> +    if (dev) {
>>>>>> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f,
>>>>>> 0), 0);
>>>>>> +        if (!r) {
>>>>>> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
>>>>>> +            pci_config_set_device_id(dev->config, hdev.device_id);
>>>
>>> Can you, instead, implement the reverse logic, probing
>>> the card and supplying the correct device id for PCH?
>>>
>>
>> Here what is your so-called reverse logic as I already asked you
>> previously? Do you mean I should list all PCHs with a combo illustrated
>> with the vendor/device id in advance? Then look up if we can find a
>
> Michael,
>

Ping.

Thanks
Tiejun

> Could you explain this exactly? Then I can try follow-up your idea ASAP
> if this is necessary and possible.
>
> Thanks
> Tiejun
>
>> matched PCH? If yes, what is that benefit you expect in passthrough
>> case? Shouldn't we pass these info to VM directly in passthrough case?
>>
>> Thanks
>> Tiejun
>>
>>
>>
>
>
>

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]

On 2014/8/28 8:56, Chen, Tiejun wrote:
>>>>>>> +     */
>>>>>>> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
>>>>>>> +                            "xen-igd-passthrough-isa-bridge");
>>>>>>> +    if (dev) {
>>>>>>> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f,
>>>>>>> 0), 0);
>>>>>>> +        if (!r) {
>>>>>>> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
>>>>>>> +            pci_config_set_device_id(dev->config, hdev.device_id);
>>>>
>>>> Can you, instead, implement the reverse logic, probing
>>>> the card and supplying the correct device id for PCH?
>>>>
>>>
>>> Here what is your so-called reverse logic as I already asked you
>>> previously? Do you mean I should list all PCHs with a combo illustrated
>>> with the vendor/device id in advance? Then look up if we can find a
>>
>> Michael,
>>
>
> Ping.
>
> Thanks
> Tiejun
>
>> Could you explain this exactly? Then I can try follow-up your idea ASAP
>> if this is necessary and possible.

Michel,

Could you give us some explanation for your "reverse logic" when you're 
free?

Thanks
Tiejun

>>
>> Thanks
>> Tiejun
>>
>>> matched PCH? If yes, what is that benefit you expect in passthrough
>>> case? Shouldn't we pass these info to VM directly in passthrough case?
>>>
>>> Thanks
>>> Tiejun
>>>
>>>
>>>
>>
>>
>>
>
>
>

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Michael S. Tsirkin]

On Fri, Aug 29, 2014 at 09:28:50AM +0800, Chen, Tiejun wrote:
> 
> 
> On 2014/8/28 8:56, Chen, Tiejun wrote:
> >>>>>>>+     */
> >>>>>>>+    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
> >>>>>>>+                            "xen-igd-passthrough-isa-bridge");
> >>>>>>>+    if (dev) {
> >>>>>>>+        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f,
> >>>>>>>0), 0);
> >>>>>>>+        if (!r) {
> >>>>>>>+            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
> >>>>>>>+            pci_config_set_device_id(dev->config, hdev.device_id);
> >>>>
> >>>>Can you, instead, implement the reverse logic, probing
> >>>>the card and supplying the correct device id for PCH?
> >>>>
> >>>
> >>>Here what is your so-called reverse logic as I already asked you
> >>>previously? Do you mean I should list all PCHs with a combo illustrated
> >>>with the vendor/device id in advance? Then look up if we can find a
> >>
> >>Michael,
> >>
> >
> >Ping.
> >
> >Thanks
> >Tiejun
> >
> >>Could you explain this exactly? Then I can try follow-up your idea ASAP
> >>if this is necessary and possible.
> 
> Michel,
> 
> Could you give us some explanation for your "reverse logic" when you're
> free?
> 
> Thanks
> Tiejun

So future drivers will look at device ID for the card
and figure out how things should work from there.
Old drivers still poke at device id of the chipset for this,
but maybe qemu can do what newer drivers do:
look at the card and figure out what guest should do,
then present the appropriate chipset id.

This is based on what Jesse said:
	Practically speaking, we could probably assume specific GPU/PCH combos,
	as I don't think they're generally mixed across generations, though SNB
	and IVB did have compatible sockets, so there is the possibility of
	mixing CPT and PPT PCHs, but those are register identical as far as the
	graphics driver is concerned, so even that should be safe.

so the idea is to have a reverse table mapping GPU back to PCH.
Present to guest the ID that will let it assume the correct GPU.

the problem with these tables is they are hard to keep up to date
as new hardware comes out, but as future hardware won't need
these hacks, we shall be fine.


> >>
> >>Thanks
> >>Tiejun
> >>
> >>>matched PCH? If yes, what is that benefit you expect in passthrough
> >>>case? Shouldn't we pass these info to VM directly in passthrough case?
> >>>
> >>>Thanks
> >>>Tiejun
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >
> >
> >

Re: [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]