[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 4/4] hvmloader: add support to load extra ACPI tables from qemu
> >>>>c) hotplug support > >>> > >>>How does that work? Ah the _DSM will point to the new ACPI NFIT for the OS > >>>to scan. That would require the hypervisor also reading this for it to > >>>update it's data-structures. > >> > >>Similar as you said. The NVDIMM root device in SSDT/DSDT dedicates a new > >>interface, > >>_FIT, which return the new NFIT once new device hotplugged. And yes, domain > >>0 is > >>the better place handing this case too. > > > >That one is a bit difficult. Both the OS and the hypervisor would need to > >know about > >this (I think?). dom0 since it gets the ACPI event and needs to process it. > >Then > >the hypervisor needs to be told so it can slurp it up. > > Can dom0 receive the interrupt triggered by device hotplug? If yes, we can > let dom0 Yes of course it can. > handle all the things like native. If it can not, dom0 can interpret ACPI and > fetch > the irq info out and tell hypervior to pass the irq to dom0, it is doable? > > > > >However I don't know if the hypervisor needs to know all the details of an > >NVDIMM - or just the starting and ending ranges so that when an guest is > >created > >and the VT-d is constructed - it can be assured that the ranges are valid. > > > >I am not an expert on the P2M code - but I think that would need to be looked > >at to make sure it is OK with stitching an E820_NVDIMM type "MFN" into an > >guest PFN. > > We do better do not use "E820" as it lacks some advantages of ACPI, such as, > NUMA, hotplug, > lable support (namespace)... <hand-waves> I don't know what QEMU does for guests? I naively assumed it would create an E820_NVDIMM along with the ACPI MADT NFIT tables (and the SSDT to have the _DSM). Either way what I think you need to investigate is what is neccessary for the Xen hypervisor VT-d code (IOMMU) to have an entry which is the system address for the NVDIMM. Based on that - you will know what kind of exposure the hypervisor needs to the _FIT and NFIT tables. (Adding Feng Wu, the VT-d maintainer). _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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