Anthony Liguori wrote: > Gregory Haskins wrote: >> >> Today, there is no equivelent of a platform agnostic "iowrite32()" for >> hypercalls so the driver would look like the pseudocode above except >> substitute with kvm_hypercall(), lguest_hypercall(), etc. The proposal >> is to allow the hypervisor to assign a dynamic vector to resources in >> the backend and convey this vector to the guest (such as in PCI >> config-space as mentioned in my example use-case). The provides the >> "address negotiation" function that would normally be done for something >> like a pio port-address. The hypervisor agnostic driver can then use >> this globally recognized address-token coupled with other device-private >> ABI parameters to communicate with the device. This can all occur >> without the core hypervisor needing to understand the details beyond the >> addressing. >> > > PCI already provide a hypervisor agnostic interface (via IO regions). > You have a mechanism for devices to discover which regions they have > allocated and to request remappings. It's supported by Linux and > Windows. It works on the vast majority of architectures out there today. > > Why reinvent the wheel? I suspect the current wheel is square. And the air is out. Plus its pulling to the left when I accelerate, but to be fair that may be my alignment.... :) But I digress. See: http://patchwork.kernel.org/patch/21865/ To give PCI proper respect, I think its greatest value add here is the inherent IRQ routing (which is a huge/difficult component, as I experienced with dynirq in vbus v1). Beyond that, however, I think we can do better. HTH -Greg
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