2014-06-27 17:55 GMT+08:00 Jan Kiszka <jan.kis...@web.de>: > On 2014-06-27 07:46, Le Tan wrote: >> 2014-06-27 12:55 GMT+08:00 Paolo Bonzini <pbonz...@redhat.com>: >>> Il 27/06/2014 04:08, Le Tan ha scritto: >>> >>>> 1. In struct IOMMUTLBEntry, I think the addr_mask field should be the >>>> mask of the page offset, right? But I see different usages of this >>>> field. In spapr_tce_translate_iommu(), the addr_mask field is assigned >>>> with the mask of the page offset. However, in pbm_translate_iommu(), >>>> in the passthrough case, the addr_mask field seems to be assigned the >>>> mask of the page number. Is there any problem here? >>> >>> >>> The intended usage is the one of spapr_tce_translate_iommu(). In practice >>> it doesn't matter, both work. >>> >>> >>>> 2. For q35, how to identify origination of DMA requests? The VT-d >>>> manual says we should use source-id(for PCI-Express devices, it is >>>> requester identifier) to map devices to domains. What is the related >>>> part in QEMU? Where can I get the source-id of a DMA request? >>> >>> >>> You need to create a different AddressSpace for each PCI bus or device. >> >> How to create a different AddressSpace for each device? I thought a >> AddressSpace just belongs to a PCI bus before. The paging structures >> for different functions of the same device can also be different, too. >> So maybe we should create a different AddressSpace for each function? >> How to achieve it? Could you give me some more hints or is there any >> existing example in QEMU? > > I would suggest to study the apb IOMMU implementation Paolo referenced > and the PCI layer functions used by that code. Specifically, > pci_setup_iommu takes a callback that is supposed to return an address > space to be used for a particular device. For apb, it's the same for all > devices on a bus, but that's not required...
Yeah, I notice that the third parameter passed to bus->iommu_fn() is the key. That is the dev->devfn, which is the combination of #device and #function. I was so careless that I didn't noticed this field. I think I am getting close to the answer. I will dive into this later. :） Thanks very much! Regards, Le > > Jan > >
