[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Query] Flow of PCI device dedicated to a domU
On Tue, 2014-07-22 at 16:56 +0100, Simon Martin wrote: > Hello Stefano, > > > The basic mechanism is that Xen assigns the PCI root complex/host > > bridge to Dom0. Dom0 walks the bus and finds out the devices available. > > > When the user assigns a PCI device to a VM, the toolstack (xl/libxl) > > issues hypercalls to remap interrupts and MMIO regions of that device > > into the guest VM. > > I am currently trying writing my own PCI front to access directly a > PCI device from my PV guest. > > If I read this correctly you are saying that the MMIO region is > already mapped into my domain by xl? So when I go and read the BAR > register from the PCI configuration I can just go and access it > directly or do I have to update the VA mapping? Stefano meant mapped in the p2m which under ARM or x86 HVM still means you need to make a virtual mapping of those PFNs. Under X86 PV "mapping" in this context really just means giving permission to map the underlying MFNs, so you still need to create a virtual mapping but they don't exist in your p2m until you put them there. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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