On 12/13/2016 06:09 AM, Michael S. Tsirkin wrote:
> On Mon, Dec 12, 2016 at 04:57:30PM -0200, Eduardo Habkost wrote:
>> On Mon, Dec 12, 2016 at 08:41:41PM +0200, Michael S. Tsirkin wrote:
>>> On Mon, Dec 12, 2016 at 05:29:15PM +0000, Stefan Hajnoczi wrote:
>>>> On Mon, Dec 12, 2016 at 01:34:05PM +0800, Cao jin wrote:
>>>>>
>>>>>
>>>>> On 12/10/2016 04:39 AM, Eduardo Habkost wrote:
>>>>>> Using latest qemu.git master:
>>>>>>
>>>>>> $ qemu-system-x86_64 -machine q35 -readconfig docs/q35-chipset.cfg
>>>>>> -monitor stdio
>>>>>> QEMU 2.7.93 monitor - type 'help' for more information
>>>>>> (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=00
>>>>>> (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=08
>>>>>> Segmentation fault (core dumped)
>>>>>>
>>>>>> It crashes at:
>>>>>>
>>>>>> #7 0x000055555598d7dc in do_pci_register_device (errp=0x7fffffffbfd0,
>>>>>> devfn=64, name=0x5555565df340 "e1000e", bus=0x555558487380,
>>>>>> pci_dev=0x5555589cd000)
>>>>>> at /home/ehabkost/rh/proj/virt/qemu/hw/pci/pci.c:983
>>>>>> 983 error_setg(errp, "PCI: slot %d function 0 already
>>>>>> ocuppied by %s,"
>>>>>> (gdb) l
>>>>>> 978 PCI_SLOT(devfn), PCI_FUNC(devfn), name,
>>>>>> 979 bus->devices[devfn]->name);
>>>>>> 980 return NULL;
>>>>>> 981 } else if (dev->hotplugged &&
>>>>>> 982 pci_get_function_0(pci_dev)) {
>>>>>> 983 error_setg(errp, "PCI: slot %d function 0 already
>>>>>> ocuppied by %s,"
>>>>>> 984 " new func %s cannot be exposed to guest.",
>>>>>> 985 PCI_SLOT(devfn),
>>>>>> 986 bus->devices[PCI_DEVFN(PCI_SLOT(devfn),
>>>>>> 0)]->name,
>>>>>> 987 name);
>>>>>>
>>>>>
>>>>> Thanks for informing me. I am kind of busy for now, so I suppose I will
>>>>> investigate it after 2.8 release.
>>>>
>>>> Please let me know if this should be considered a release blocker.
>>>>
>>>> The proposed QEMU 2.8 release date is tomorrow (December 13th)!
>>>>
>>>> Stefan
>>>
>>> I don't see how it's a blocker, it's an illegal configuration.
>>> Here's the fix. It's a rather obvious one.
>>> I'll target the fix for 2.9.
>>> Eduardo, I'd appreciate a tested-by tag.
>>
>> I confirm the patch fixes the crash, but the error message seems
>> incorrect: the existing e1000e device is on slot 0 function 0,
>> not slot 8.
>>
>> $ ./x86-kvm-build/x86_64-softmmu/qemu-system-x86_64 -machine q35
>> -readconfig docs/q35-chipset.cfg -monitor stdio
>> QEMU 2.7.93 monitor - type 'help' for more information
>> (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=00
>> (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=08
>> PCI: slot 8 function 0 already ocuppied by e1000e, new func e1000e cannot
>> be exposed to guest.
>> ^^^
>>
>>
>>>
>>> -->
>>>
>>> pci: fix error message for express slots
>>>
>>> PCI Express downstream slot has a single PCI slot
>>> behind it, using PCI_DEVFN(PCI_SLOT(devfn), 0)
>>> does not give you function 0 in cases such as ARI
>>> as well as some error cases.
>>>
>>> This is exactly what we are hitting:
>>> $ qemu-system-x86_64 -machine q35 -readconfig docs/q35-chipset.cfg
>>> -monitor stdio
>>> (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=00
>>> (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=08
>>> Segmentation fault (core dumped)
>>>
>>> The fix is to use the pci_get_function_0 API.
>>>
>>> Cc: qemu-sta...@nongnu.org
>>> Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
>>> Reported-by: Eduardo Habkost <ehabk...@redhat.com>
>>> ---
>>>
>>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>>> index 24fae16..339c531 100644
>>> --- a/hw/pci/pci.c
>>> +++ b/hw/pci/pci.c
>>> @@ -983,7 +983,7 @@ static PCIDevice *do_pci_register_device(PCIDevice
>>> *pci_dev, PCIBus *bus,
>>> error_setg(errp, "PCI: slot %d function 0 already ocuppied by %s,"
>>> " new func %s cannot be exposed to guest.",
>>> PCI_SLOT(devfn),
>>> - bus->devices[PCI_DEVFN(PCI_SLOT(devfn), 0)]->name,
>>> + pci_get_function_0(pci_dev)->name,
>>> name);
>>>
>>> return NULL;
>>>
>>> --
>>> MST
>>
>> --
>
>
>
> this then?
>
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 339c531..637d545 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -982,7 +982,7 @@ static PCIDevice *do_pci_register_device(PCIDevice
> *pci_dev, PCIBus *bus,
> pci_get_function_0(pci_dev)) {
> error_setg(errp, "PCI: slot %d function 0 already ocuppied by %s,"
> " new func %s cannot be exposed to guest.",
> - PCI_SLOT(devfn),
> + PCI_SLOT(pci_get_function_0(pci_dev)->devfn),
> pci_get_function_0(pci_dev)->name,
> name);
>
Tested-by: Cao jin <caoj.f...@cn.fujitsu.com>
./qemu-system-x86_64 -machine q35 -readconfig ../docs/q35-chipset.cfg
-monitor stdio
QEMU 2.7.91 monitor - type 'help' for more information
(qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=00
(qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=08
PCI: slot 0 function 0 already ocuppied by e1000e, new func e1000e
cannot be exposed to guest.
--
Sincerely,
Cao jin
