On Di, 2015-03-03 at 10:32 +0000, Gordan Bobic wrote: > I need to pass a custom e820 map to a virtual machine for > troubleshooting purposes and working around IOMMU hardware > bugs. > > I have found references to a custom map being providable > via an external file, mentioned as "etc/e820" and "fw_cfg".
That is the (filesystem-like) interface between qemu and firmware (seabios usually), it doesn't refer to a on-disk file. > Unfortunately, I have not found any documentation that > explains how to use this from userspace when invoking > qemu. You can't. Passing a different e820 map requires patching qemu (or seabios, which mangles the e820 table to add reservations for acpi etc). What exactly do you need? cheers, Gerd