[PATCH -v3 2/2] x86: Make Linux guest support optional

[Borislav Petkov]

From: Borislav Petkov <bp@xxxxxxx>

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.

While at it, adjust text to changes, remove redundant select.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Dmitry Torokhov <dtor@xxxxxxxxxx>
Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: devel@xxxxxxxxxxxxxxxxxxxxxx
---
 arch/x86/Kconfig                  | 21 +++++++++++----------
 arch/x86/include/asm/hypervisor.h | 12 ++++++++----
 arch/x86/kernel/cpu/Makefile      |  3 ++-
 drivers/hv/Kconfig                |  2 +-
 drivers/misc/Kconfig              |  2 +-
 5 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 201b8aa93f8f..2380a52f0c8c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -379,7 +379,7 @@ 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
@@ -568,15 +568,17 @@ 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
+if HYPERVISOR_GUEST
 
 config PARAVIRT_TIME_ACCOUNTING
 	bool "Paravirtual steal time accounting"
@@ -595,9 +597,8 @@ 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
+	default y
 	---help---
 	  This option enables various optimizations for running under the KVM
 	  hypervisor. It includes a paravirtualized clock, so that instead
@@ -638,7 +639,7 @@ config PARAVIRT_DEBUG
 	  Enable to debug paravirt_ops internals.  Specifically, BUG if
 	  a paravirt_op is missing when it is called.
 
-endif #PARAVIRT_GUEST
+endif #HYPERVISOR_GUEST
 
 config NO_BOOTMEM
 	def_bool y
diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index b518c7509933..cd06ed8733cb 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -23,9 +23,6 @@
 #include <asm/kvm_para.h>
 #include <asm/xen/hypervisor.h>
 
-extern void init_hypervisor(struct cpuinfo_x86 *c);
-extern void init_hypervisor_platform(void);
-
 /*
  * x86 hypervisor information
  */
@@ -60,4 +57,11 @@ static inline bool hypervisor_x2apic_available(void)
 	return false;
 }
 
-#endif
+#ifdef CONFIG_PARAVIRT
+extern void init_hypervisor(struct cpuinfo_x86 *c);
+extern void init_hypervisor_platform(void);
+#else
+static inline void init_hypervisor(struct cpuinfo_x86 *c) { }
+static inline void init_hypervisor_platform(void) { }
+#endif /* CONFIG_PARAVIRT */
+#endif /* _ASM_X86_HYPERVISOR_H */
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index a0e067d3d96c..8d04c7cd7cd3 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -14,7 +14,6 @@ CFLAGS_common.o		:= $(nostackp)
 
 obj-y			:= intel_cacheinfo.o scattered.o topology.o
 obj-y			+= proc.o capflags.o powerflags.o common.o
-obj-y			+= vmware.o hypervisor.o mshyperv.o
 obj-y			+= rdrand.o
 obj-y			+= match.o
 
@@ -42,6 +41,8 @@ obj-$(CONFIG_MTRR)			+= mtrr/
 
 obj-$(CONFIG_X86_LOCAL_APIC)		+= perfctr-watchdog.o perf_event_amd_ibs.o
 
+obj-$(CONFIG_PARAVIRT)			+= vmware.o hypervisor.o mshyperv.o
+
 quiet_cmd_mkcapflags = MKCAP   $@
       cmd_mkcapflags = $(PERL) $(srctree)/$(src)/mkcapflags.pl $< $@
 
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index b38ef6d8d049..e05efc46744f 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -2,7 +2,7 @@ menu "Microsoft Hyper-V guest support"
 
 config HYPERV
 	tristate "Microsoft Hyper-V client drivers"
-	depends on X86 && ACPI && PCI
+	depends on X86 && ACPI && PCI && HYPERVISOR_GUEST
 	help
 	  Select this option to run Linux as a Hyper-V client operating
 	  system.
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index b151b7c1bd59..c7092d5078e1 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -418,7 +418,7 @@ config TI_DAC7512
 
 config VMWARE_BALLOON
 	tristate "VMware Balloon Driver"
-	depends on X86
+	depends on X86 && HYPERVISOR_GUEST
 	help
 	  This is VMware physical memory management driver which acts
 	  like a "balloon" that can be inflated to reclaim physical pages
-- 
1.8.1.rc3

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