x86: KVM guest: paravirtualized clocksource
This is the guest part of kvm clock implementation
It does not do tsc-only timing, as tsc can have deltas
between cpus, and it did not seem worthy to me to keep
adjusting them.
We do use it, however, for fine-grained adjustment.
Other than that, time comes from the host.
[randy dunlap: add missing include]
[randy dunlap: disallow on Voyager or Visual WS]
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2fadf79..40cedc2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -373,6 +373,17 @@
at the moment), by linking the kernel to a GPL-ed ROM module
provided by the hypervisor.
+config KVM_CLOCK
+ bool "KVM paravirtualized clock"
+ select PARAVIRT
+ depends on !(X86_VISWS || X86_VOYAGER)
+ help
+ Turning on this option will allow you to run a paravirtualized clock
+ when running over the KVM hypervisor. Instead of relying on a PIT
+ (or probably other) emulation by the underlying device model, the host
+ provides the guest with timing infrastructure such as time of day, and
+ system time
+
source "arch/x86/lguest/Kconfig"
config PARAVIRT