Replace unreliable host KVM detection with better guest detection

This will detect hvm KVM guests

2 files changed, 13 insertions, 11 deletions

diff --git a/lib/ohai/plugins/linux/virtualization.rb b/lib/ohai/plugins/linux/virtualization.rb
index d681bc5d..674b892d 100644
--- a/lib/ohai/plugins/linux/virtualization.rb
+++ b/lib/ohai/plugins/linux/virtualization.rb
@@ -64,14 +64,10 @@ Ohai.plugin(:Virtualization) do
     # - Additional edge cases likely should not change the above assumptions
     #   but rather be additive - btm
 
-    # Detect from kernel module
+    # Detect Virtualbox from kernel module
     if File.exist?("/proc/modules")
       modules = File.read("/proc/modules")
-      if modules =~ /^kvm/
-        virtualization[:system] = "kvm"
-        virtualization[:role] = "host"
-        virtualization[:systems][:kvm] = "host"
-      elsif modules =~ /^vboxdrv/
+      if modules =~ /^vboxdrv/
         virtualization[:system] = "vbox"
         virtualization[:role] = "host"
         virtualization[:systems][:vbox] = "host"
@@ -95,6 +91,13 @@ Ohai.plugin(:Virtualization) do
       end
     end
 
+    # Detect KVM guests via /sys/ data
+    if File.exist?("/sys/devices/virtual/misc/kvm")
+      virtualization[:system] = "kvm"
+      virtualization[:role] = "guest"
+      virtualization[:systems][:kvm] = "guest"
+    end
+
     # Detect OpenVZ / Virtuozzo.
     # http://wiki.openvz.org/BC_proc_entries
     if File.exist?("/proc/bc/0")
diff --git a/spec/unit/plugins/linux/virtualization_spec.rb b/spec/unit/plugins/linux/virtualization_spec.rb
index 91afd507..ff80f665 100644
--- a/spec/unit/plugins/linux/virtualization_spec.rb
+++ b/spec/unit/plugins/linux/virtualization_spec.rb
@@ -77,13 +77,12 @@ describe Ohai::System, "Linux virtualization platform" do
   end
 
   describe "when we are checking for kvm" do
-    it "sets kvm host if /proc/modules contains kvm" do
-      expect(File).to receive(:exist?).with("/proc/modules").and_return(true)
-      allow(File).to receive(:read).with("/proc/modules").and_return("kvm 165872  1 kvm_intel")
+    it "sets kvm guest if /sys/devices/virtual/misc/kvm exists" do
+      expect(File).to receive(:exist?).with("/sys/devices/virtual/misc/kvm").and_return(true)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("kvm")
-      expect(plugin[:virtualization][:role]).to eq("host")
-      expect(plugin[:virtualization][:systems][:kvm]).to eq("host")
+      expect(plugin[:virtualization][:role]).to eq("guest")
+      expect(plugin[:virtualization][:systems][:kvm]).to eq("guest")
     end
 
     it "sets kvm guest if /proc/cpuinfo contains QEMU Virtual CPU" do