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Re: [PATCH v2 7/7] libqos: add VIRTIO PCI 1.0 support
From: |
Thomas Huth |
Subject: |
Re: [PATCH v2 7/7] libqos: add VIRTIO PCI 1.0 support |
Date: |
Thu, 17 Oct 2019 18:18:14 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
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
Thomas
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