Re: [Xen-devel] [PATCH v7 2/2] VT-d: Fix vt-d Device-TLB flush timeout issue

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 17.03.16 at 12:13, <kevin.tian@xxxxxxxxx> wrote:
>>  From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
>> Sent: Thursday, March 17, 2016 5:43 PM
>> 
>> >>> On 17.03.16 at 09:17, <kevin.tian@xxxxxxxxx> wrote:
>> >>  From: Xu, Quan
>> >> Sent: Thursday, March 17, 2016 3:13 PM
>> >> --- a/xen/drivers/passthrough/vtd/qinval.c
>> >> +++ b/xen/drivers/passthrough/vtd/qinval.c
>> >> @@ -233,6 +233,57 @@ int qinval_device_iotlb(struct iommu *iommu,
>> >>      return 0;
>> >>  }
>> >>
>> >> +static void dev_invalidate_iotlb_timeout(struct iommu *iommu, u16 did,
>> >> +                                         u16 seg, u8 bus, u8 devfn)
>> >> +{
>> >> +    struct domain *d = NULL;
>> >> +    struct pci_dev *pdev;
>> >> +
>> >> +    if ( test_bit(did, iommu->domid_bitmap) )
>> >> +        d = rcu_lock_domain_by_id(iommu->domid_map[did]);
>> >> +
>> >> +    if ( d == NULL )
>> >> +        return;
>> >> +
>> >> +    pcidevs_lock();
>> >> +    for_each_pdev(d, pdev)
>> >
>> > we need a 'safe' version here since you're deleting nodes
>> > when walking list. for_each_pdev today is based on
>> > list_for_each_entry. Or if it's sure that only one pdev
>> > can match, we can break out of the loop to do removal.
>> 
>> But breaking out of the loop is what is already being done ...
>> 
>> >> +    {
>> >> +        if ( ( pdev->seg == seg ) &&
>> >> +             ( pdev->bus == bus ) &&
>> >> +             ( pdev->devfn == devfn ) )
>> >> +        {
>> >> +            ASSERT ( pdev->domain );
>> >> +            list_del(&pdev->domain_list);
>> >> +            pdev->domain = NULL;
>> >> +            pci_hide_existing_device(pdev);
>> >> +            break;
>> 
>> ... here.
>> 
> 
> however you see list_del happens before breaking out, right?

I'm sorry Kevin, but ???

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel