Hello ARM virt maintainers, I'd like to start a discussion about supporting virt-what[1]. virt-what allows userspace to determine if the system it's running on is running in a guest, and of what type (KVM, Xen, etc.). Despite it being a best effort tool, see the Caveat emptor in [1], it has become quite a useful tool, and is showing up in different places, such as OpenStack. If you look at the code[2], specifically [3], then you'll see how it works on x86, which is to use the dedicated hypervisor cpuid leaves. I'm wondering what equivalent we have, or can develop, for arm. Here are some thoughts; 0) there's already something we can use, and I just need to be told about it. 1) be as similar as possible to x86 by dedicating some currently undefined sysreg bits. This would take buy-in from lots of parties, so is not likely the way to go. 2) create a specific DT node that will get exposed through sysfs, or somewhere. 3) same as (2), but just use the nodes currently in mach-virt's DT as the indication we're a guest. This would just be a heuristic, i.e. "have virtio mmio" && psci.method == hvc, or something, and we'd still need a way to know if we're kvm vs. xen vs. ??. Thanks, drew [1] http://people.redhat.com/~rjones/virt-what/ [2] http://git.annexia.org/?p=virt-what.git;a=summary [3] http://git.annexia.org/?p=virt-what.git;a=blob_plain;f=virt-what-cpuid-helper.c;hb=HEAD -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
