Merge branch kvm-arm64/misc-5.16 into kvmarm-master/next

* kvm-arm64/misc-5.16:
  : .
  : - Allow KVM to be disabled from the command-line
  : - Clean up CONFIG_KVM vs CONFIG_HAVE_KVM
  : .
  KVM: arm64: Depend on HAVE_KVM instead of OF
  KVM: arm64: Unconditionally include generic KVM's Kconfig
  KVM: arm64: Allow KVM to be disabled from the command line

Signed-off-by: Marc Zyngier <[email protected]>

Author: Marc Zyngier

Documentation/admin-guide/kernel-parameters.txt

@@ -2365,6 +2365,8 @@
 	kvm-arm.mode=
 			[KVM,ARM] Select one of KVM/arm64's modes of operation.
 
+			none: Forcefully disable KVM.
+
 			nvhe: Standard nVHE-based mode, without support for
 			      protected guests.
 

arch/arm64/Kconfig

@@ -186,6 +186,7 @@ config ARM64
 	select HAVE_GCC_PLUGINS
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS
 	select HAVE_IRQ_TIME_ACCOUNTING
+	select HAVE_KVM
 	select HAVE_NMI
 	select HAVE_PATA_PLATFORM
 	select HAVE_PERF_EVENTS

arch/arm64/include/asm/kvm_host.h

@@ -58,6 +58,7 @@
 enum kvm_mode {
 	KVM_MODE_DEFAULT,
 	KVM_MODE_PROTECTED,
+	KVM_MODE_NONE,
 };
 enum kvm_mode kvm_get_mode(void);
 

arch/arm64/kvm/Kconfig

@@ -4,6 +4,7 @@
 #
 
 source "virt/lib/Kconfig"
+source "virt/kvm/Kconfig"
 
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
@@ -19,7 +20,7 @@ if VIRTUALIZATION
 
 menuconfig KVM
 	bool "Kernel-based Virtual Machine (KVM) support"
-	depends on OF
+	depends on HAVE_KVM
 	select MMU_NOTIFIER
 	select PREEMPT_NOTIFIERS
 	select HAVE_KVM_CPU_RELAX_INTERCEPT
@@ -43,19 +44,14 @@ menuconfig KVM
 
 	  If unsure, say N.
 
-if KVM
-
-source "virt/kvm/Kconfig"
-
 config NVHE_EL2_DEBUG
 	bool "Debug mode for non-VHE EL2 object"
+	depends on KVM
 	help
 	  Say Y here to enable the debug mode for the non-VHE KVM EL2 object.
 	  Failure reports will BUG() in the hypervisor. This is intended for
 	  local EL2 hypervisor development.
 
 	  If unsure, say N.
 
-endif # KVM
-
 endif # VIRTUALIZATION

arch/arm64/kvm/arm.c

@@ -2087,6 +2087,11 @@ int kvm_arch_init(void *opaque)
 		return -ENODEV;
 	}
 
+	if (kvm_get_mode() == KVM_MODE_NONE) {
+		kvm_info("KVM disabled from command line\n");
+		return -ENODEV;
+	}
+
 	in_hyp_mode = is_kernel_in_hyp_mode();
 
 	if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE) ||
@@ -2160,8 +2165,15 @@ static int __init early_kvm_mode_cfg(char *arg)
 		return 0;
 	}
 
-	if (strcmp(arg, "nvhe") == 0 && !WARN_ON(is_kernel_in_hyp_mode()))
+	if (strcmp(arg, "nvhe") == 0 && !WARN_ON(is_kernel_in_hyp_mode())) {
+		kvm_mode = KVM_MODE_DEFAULT;
 		return 0;
+	}
+
+	if (strcmp(arg, "none") == 0) {
+		kvm_mode = KVM_MODE_NONE;
+		return 0;
+	}
 
 	return -EINVAL;
 }