On 2011-08-24 13:58, Michael S. Tsirkin wrote:
> On Wed, Aug 24, 2011 at 12:10:32PM +0200, Jan Kiszka wrote:
>> On 2011-08-24 12:04, Michael S. Tsirkin wrote:
>>> On Tue, Aug 23, 2011 at 07:28:08PM +0200, Jan Kiszka wrote:
>>>> From: Alex Williamson <alex.william...@redhat.com>
>>>>
>>>> Nothing good can happen when we overlap capabilities
>>>>
>>>> [ Jan: rebased over qemu, minor formatting ]
>>>>
>>>> Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
>>>
>>> This doesn't build for me:
>>>
>>> /scm/qemu/hw/pci.c: In function ‘pci_add_capability’:
>>> /scm/qemu/hw/pci.c:1970:45: error: ‘PCIDevice’ has no member named
>>> ‘config_map’
>>
>> Yeah, sorry, forgot to refresh the commit before posting.
>>
>>>
>>> I think that what that includes is the capability including each given
>>> offset, right? It would be easy to write some code scanning the
>>> capability list to figure this value out.
>>> Something along the lines of (untested):
>>>
>>> static
>>> uint8_t pci_find_capability_at_offset(PCIDevice *pdev, uint8_t offset)
>>> {
>>> uint8_t next, prev, found = 0;
>>>
>>> if (!(pdev->config[PCI_STATUS] & PCI_STATUS_CAP_LIST))
>>> return 0;
>>>
>>> for (prev = PCI_CAPABILITY_LIST; (next = pdev->config[prev]);
>>> prev = next + PCI_CAP_LIST_NEXT)
>>> if (next <= offset && next > found)
>>> found = next;
>>>
>>> return found;
>>> }
>>
>> Sounds useful, will enhance the patch.
>>
>> (Originally, I just wanted to reduce the qemu-kvm delta... :) )
>>
>> Jan
>
> Also, let's add a comment documenting the
> reason for this check: device assignment
> depends on this check to verify that the device
> is not broken.
Based on the previous discussion, I don't think this is accurate as it
will also validate emulated devices.
Jan
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