[RFC PATCH 53/73] x86/pvm: Add Kconfig option and the CPU feature bit for PVM guest

[Lai Jiangshan]

From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>

Add the configuration option CONFIG_PVM_GUEST to enable the building of
a PVM guest. Introduce a new CPU feature bit to control the behavior of
the PVM guest.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>
Signed-off-by: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx>
---
 arch/x86/Kconfig                         | 8 ++++++++
 arch/x86/include/asm/cpufeatures.h       | 1 +
 arch/x86/include/asm/disabled-features.h | 8 +++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index d02ef3bdb171..2ccc8a27e081 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -851,6 +851,14 @@ config KVM_GUEST
 	  underlying device model, the host provides the guest with
 	  timing infrastructure such as time of day, and system time
 
+config PVM_GUEST
+	bool "PVM Guest support"
+	depends on X86_64 && KVM_GUEST
+	default n
+	help
+	  This option enables the kernel to run as a PVM guest under the PVM
+	  hypervisor.
+
 config ARCH_CPUIDLE_HALTPOLL
 	def_bool n
 	prompt "Disable host haltpoll when loading haltpoll driver"
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 4af140cf5719..e17e72f13423 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -237,6 +237,7 @@
 #define X86_FEATURE_PVUNLOCK		( 8*32+20) /* "" PV unlock function */
 #define X86_FEATURE_VCPUPREEMPT		( 8*32+21) /* "" PV vcpu_is_preempted function */
 #define X86_FEATURE_TDX_GUEST		( 8*32+22) /* Intel Trust Domain Extensions Guest */
+#define X86_FEATURE_KVM_PVM_GUEST	( 8*32+23) /* KVM Pagetable-based Virtual Machine guest */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 702d93fdd10e..5d56e804ab18 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -105,6 +105,12 @@
 # define DISABLE_TDX_GUEST	(1 << (X86_FEATURE_TDX_GUEST & 31))
 #endif
 
+#ifdef CONFIG_PVM_GUEST
+#define DISABLE_KVM_PVM_GUEST	0
+#else
+#define DISABLE_KVM_PVM_GUEST	(1 << (X86_FEATURE_KVM_PVM_GUEST & 31))
+#endif
+
 #ifdef CONFIG_X86_USER_SHADOW_STACK
 #define DISABLE_USER_SHSTK	0
 #else
@@ -128,7 +134,7 @@
 #define DISABLED_MASK5	0
 #define DISABLED_MASK6	0
 #define DISABLED_MASK7	(DISABLE_PTI)
-#define DISABLED_MASK8	(DISABLE_XENPV|DISABLE_TDX_GUEST)
+#define DISABLED_MASK8	(DISABLE_XENPV|DISABLE_TDX_GUEST|DISABLE_KVM_PVM_GUEST)
 #define DISABLED_MASK9	(DISABLE_SGX)
 #define DISABLED_MASK10	0
 #define DISABLED_MASK11	(DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
-- 
2.19.1.6.gb485710b