[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] RE: one question to PHYSDEVOP_manage_pci_remove
Espen Skoglund <mailto:espen.skoglund@xxxxxxxxxxxxx> wrote: > The idea was to use PHYSDEVOP_manage_pci_{add,remove} for > hot-pluggable devices and SR-IOV or ARI capable devices. In general, > when a new PCI device function is added or removed during runtime, > dom0 will invoke the hypercall to register or unrigister the > corresponding struct pci_dev within Xen. > > Xen clears the VT-d entry because the device is about to be removed > from the system --- either physically removed or just completely > disabled by dom0. The device is forcibly removed from the guest if it > is assigned to one. It is up to dom0 to do the actual device > reassignment. Although the device can not access any host memory I > suppose it would not hurt to also do deassign_device() when the device > is removed. This would tear down the IOMMU page tables for the domain > if they are not needed anymore. > > eSk Thanks for your information, so I think at least a log is needed if the device is still assigned to a guest. Also, have you checked if dom0 have chance to "do the actual device reassignment"? I suppose user space tools should be involeved in such process. Thanks Yunhong Jiang > > > [Yunhong Jiang] >> Hi, Espen, when I'm working on the MSI lock issue, I have one >> question to PHYSDEVOP_manage_pci_remove. From the kernel, seems it >> will happen for PCI device remove. Is it target only for pci >> hotplug? > >> I asked this because I noticed that in current code, it will always >> clear the VT-d entry, no matter if the device is owned by other >> domain, I'm not sure if it reqiures the device is not owned by a >> guest (maybe except dom0). _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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