x86: Make Linux guest support optional

Put all config options needed to run Linux as a guest behind a
CONFIG_HYPERVISOR_GUEST menu so that they don't get built-in by default
but be selectable by the user. Also, make all units which depend on
x86_hyper, depend on this new symbol so that compilation doesn't fail
when CONFIG_HYPERVISOR_GUEST is disabled but those units assume its
presence.

Sort options in the new HYPERVISOR_GUEST menu, adapt config text and
drop redundant select.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1362428421-9244-3-git-send-email-bp@alien8.de
Cc: Dmitry Torokhov <dtor@vmware.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 45 insertions, 44 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f922a9b9a319..e9e4623bd4da 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -389,7 +389,7 @@ config X86_NUMACHIP
 
 config X86_VSMP
         bool "ScaleMP vSMP"
-        select PARAVIRT_GUEST
+        select HYPERVISOR_GUEST
         select PARAVIRT
         depends on X86_64 && PCI
         depends on X86_EXTENDED_PLATFORM
@@ -596,44 +596,17 @@ config SCHED_OMIT_FRAME_POINTER
 
           If in doubt, say "Y".
 
-menuconfig PARAVIRT_GUEST
-        bool "Paravirtualized guest support"
+menuconfig HYPERVISOR_GUEST
+        bool "Linux guest support"
         ---help---
-          Say Y here to get to see options related to running Linux under
-          various hypervisors.  This option alone does not add any kernel code.
+          Say Y here to enable options for running Linux under various hyper-
+          visors. This option enables basic hypervisor detection and platform
+          setup.
 
-          If you say N, all options in this submenu will be skipped and disabled.
+          If you say N, all options in this submenu will be skipped and
+          disabled, and Linux guest support won't be built in.
 
-if PARAVIRT_GUEST
-
-config PARAVIRT_TIME_ACCOUNTING
-        bool "Paravirtual steal time accounting"
-        select PARAVIRT
-        default n
-        ---help---
-          Select this option to enable fine granularity task steal time
-          accounting. Time spent executing other tasks in parallel with
-          the current vCPU is discounted from the vCPU power. To account for
-          that, there can be a small performance impact.
-
-          If in doubt, say N here.
-
-source "arch/x86/xen/Kconfig"
-
-config KVM_GUEST
-        bool "KVM Guest support (including kvmclock)"
-        select PARAVIRT
-        select PARAVIRT
-        select PARAVIRT_CLOCK
-        default y if PARAVIRT_GUEST
-        ---help---
-          This option enables various optimizations for running under the KVM
-          hypervisor. It includes a paravirtualized clock, so that 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"
+if HYPERVISOR_GUEST
 
 config PARAVIRT
         bool "Enable paravirtualization code"
@@ -643,6 +616,13 @@ config PARAVIRT
           over full virtualization.  However, when run without a hypervisor
           the kernel is theoretically slower and slightly larger.
 
+config PARAVIRT_DEBUG
+        bool "paravirt-ops debugging"
+        depends on PARAVIRT && DEBUG_KERNEL
+        ---help---
+          Enable to debug paravirt_ops internals.  Specifically, BUG if
+          a paravirt_op is missing when it is called.
+
 config PARAVIRT_SPINLOCKS
         bool "Paravirtualization layer for spinlocks"
         depends on PARAVIRT && SMP
@@ -656,17 +636,38 @@ config PARAVIRT_SPINLOCKS
 
           If you are unsure how to answer this question, answer N.
 
-config PARAVIRT_CLOCK
-        bool
+source "arch/x86/xen/Kconfig"
 
-config PARAVIRT_DEBUG
-        bool "paravirt-ops debugging"
-        depends on PARAVIRT && DEBUG_KERNEL
+config KVM_GUEST
+        bool "KVM Guest support (including kvmclock)"
+        depends on PARAVIRT
+        select PARAVIRT_CLOCK
+        default y
         ---help---
-          Enable to debug paravirt_ops internals.  Specifically, BUG if
-          a paravirt_op is missing when it is called.
+          This option enables various optimizations for running under the KVM
+          hypervisor. It includes a paravirtualized clock, so that 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_TIME_ACCOUNTING
+        bool "Paravirtual steal time accounting"
+        depends on PARAVIRT
+        default n
+        ---help---
+          Select this option to enable fine granularity task steal time
+          accounting. Time spent executing other tasks in parallel with
+          the current vCPU is discounted from the vCPU power. To account for
+          that, there can be a small performance impact.
+
+          If in doubt, say N here.
+
+config PARAVIRT_CLOCK
+        bool
 
-endif #PARAVIRT_GUEST
+endif #HYPERVISOR_GUEST
 
 config NO_BOOTMEM
         def_bool y