Re: [PATCH v2 7/7] libqos: add VIRTIO PCI 1.0 support

[Thomas Huth]

On 18/10/2019 08.48, Thomas Huth wrote:
> On 17/10/2019 18.18, Thomas Huth wrote:
>> On 17/10/2019 18.07, Stefan Hajnoczi wrote:
>>> On Thu, Oct 17, 2019 at 04:52:54PM +0200, Thomas Huth wrote:
>>>> On 11/10/2019 10.56, Stefan Hajnoczi wrote:
>>>>> Implement the VIRTIO 1.0 virtio-pci interface.  The main change here is
>>>>> that the register layout is no longer a fixed layout in BAR 0.  Instead
>>>>> we have to iterate of PCI Capabilities to find descriptions of where
>>>>> various registers are located.  The vring registers are also more
>>>>> fine-grained, allowing for more flexible vring layouts, but we don't
>>>>> take advantage of that.
>>>>>
>>>>> Note that test cases do not negotiate VIRTIO_F_VERSION_1 yet and are
>>>>> therefore not running in VIRTIO 1.0 mode.
>>>>>
>>>>> Signed-off-by: Stefan Hajnoczi <address@hidden>
>>>>> ---
>>>>>  tests/Makefile.include           |   1 +
>>>>>  tests/libqos/virtio-pci-modern.h |  17 ++
>>>>>  tests/libqos/virtio-pci.h        |  10 +
>>>>>  tests/libqos/virtio-pci-modern.c | 412 +++++++++++++++++++++++++++++++
>>>>>  tests/libqos/virtio-pci.c        |   6 +-
>>>>>  5 files changed, 445 insertions(+), 1 deletion(-)
>>>>>  create mode 100644 tests/libqos/virtio-pci-modern.h
>>>>>  create mode 100644 tests/libqos/virtio-pci-modern.c
>>>> [...]
>>>>> +static bool probe_device_type(QVirtioPCIDevice *dev)
>>>>> +{
>>>>> +    uint16_t vendor_id;
>>>>> +    uint16_t device_id;
>>>>> +
>>>>> +    /* "Drivers MUST match devices with the PCI Vendor ID 0x1AF4" */
>>>>> +    vendor_id = qpci_config_readw(dev->pdev, PCI_VENDOR_ID);
>>>>> +    if (vendor_id != 0x1af4) {
>>>>> +        return false;
>>>>> +    }
>>>>> +
>>>>> +    /*
>>>>> +     * "Any PCI device with ... PCI Device ID 0x1000 through 0x107F 
>>>>> inclusive
>>>>> +     * is a virtio device"
>>>>> +     */
>>>>> +    device_id = qpci_config_readw(dev->pdev, PCI_DEVICE_ID);
>>>>> +    if (device_id < 0x1000 || device_id > 0x107f) {
>>>>> +        return false;
>>>>> +    }
>>>>> +
>>>>> +    /*
>>>>> +     * "Devices MAY utilize a Transitional PCI Device ID range, 0x1000 to
>>>>> +     * 0x103F depending on the device type"
>>>>> +     */
>>>>> +    if (device_id < 0x1040) {
>>>>> +        /*
>>>>> +         * "Transitional devices MUST have the PCI Subsystem Device ID 
>>>>> matching
>>>>> +         * the Virtio Device ID"
>>>>> +         */
>>>>> +        dev->vdev.device_type = qpci_config_readw(dev->pdev, 
>>>>> PCI_SUBSYSTEM_ID);
>>>>
>>>> Shouldn't you return "false" here in case the device_type is 0 ? Which
>>>> likely means that it is a legacy or broken device ...?
>>>
>>> The real decision whether to use this PCI device or not happens in
>>> probe_device_layout().  If it's broken or a legacy device then that
>>> function will fail.
>>
>> Ok, fair.
>>
>> I've added the patches to my qtest-next branch:
>>
>> https://gitlab.com/huth/qemu/tree/qtest-next
> 
>  Hi Stephan,
> 
> looks like this is breaking the virtio-blk-test in certain configurations:
> 
>  https://gitlab.com/huth/qemu/-/jobs/324085741
> 
> and:
> 
>  https://cirrus-ci.com/task/4511314474434560
> 
> Could you please have a look?

FWIW, the
 assertion failed (capacity == TEST_IMAGE_SIZE / 512): (2199023255552 ==
131072)
looks like an endianess bug to me. 2199023255552 is 131072 byte-swapped.

 Thomas

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