[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
On 01/20/16 10:41, Konrad Rzeszutek Wilk wrote: > > > > > Neither of these are sufficient however. That gets Qemu a mapping of > > > > > the NVDIMM, not the guest. Something, one way or another, has to turn > > > > > this into appropriate add-to-phymap hypercalls. > > > > > > > > > > > > > Yes, those hypercalls are what I'm going to add. > > > > > > Why? > > > > > > What you need (in a rought hand-wave way) is to: > > > - mount /dev/pmem0 > > > - mmap the file on /dev/pmem0 FS > > > - walk the VMA for the file - extract the MFN (machien frame numbers) > > > > Can this step be done by QEMU? Or does linux kernel provide some > > approach for the userspace to do the translation? > > I don't know. I would think no - as you wouldn't want the userspace > application to figure out the physical frames from the virtual > address (unless they are root). But then if you look in > /proc/<pid>/maps and /proc/<pid>/smaps there are some data there. > > Hm, /proc/<pid>/pagemaps has something intersting > > See pagemap_read function. That looks to be doing it? > Interesting and good to know this. I'll have a look at it. Thanks, Haozhong > > > > Haozhong > > > > > - feed those frame numbers to xc_memory_mapping hypercall. The > > > guest pfns would be contingous. > > > Example: say the E820_NVDIMM starts at 8GB->16GB, so an 8GB file on > > > /dev/pmem0 FS - the guest pfns are 0x200000 upward. > > > > > > However the MFNs may be discontingous as the NVDIMM could be an > > > 1TB - and the 8GB file is scattered all over. > > > > > > I believe that is all you would need to do? > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxx > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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