KVM: Add kvm trace userspace interface

This interface allows user a space application to read the trace of kvm
related events through relayfs.

Signed-off-by: Feng (Eric) Liu <eric.e.liu@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

2 files changed, 14 insertions, 0 deletions

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 76c70ab44382..8d45fabc5f3b 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -50,6 +50,17 @@ config KVM_AMD
           Provides support for KVM on AMD processors equipped with the AMD-V
           (SVM) extensions.
 
+config KVM_TRACE
+        bool "KVM trace support"
+        depends on KVM && MARKERS && SYSFS
+        select RELAY
+        select DEBUG_FS
+        default n
+        ---help---
+          This option allows reading a trace of kvm-related events through
+          relayfs.  Note the ABI is not considered stable and will be
+          modified in future updates.
+
 # OK, it's a little counter-intuitive to do this, but it puts it neatly under
 # the virtualization menu.
 source drivers/lguest/Kconfig
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 4d0c22e11f1a..c97d35c218db 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -3,6 +3,9 @@
 #
 
 common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o ioapic.o)
+ifeq ($(CONFIG_KVM_TRACE),y)
+common-objs += $(addprefix ../../../virt/kvm/, kvm_trace.o)
+endif
 
 EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm