[PATCH 3/6] KVM: arm64: Ignore 'kvm-arm.mode=protected' when using VHE

[Will Deacon]

Ignore 'kvm-arm.mode=protected' when using VHE so that kvm_get_mode()
only returns KVM_MODE_PROTECTED on systems where the feature is available.

Cc: David Brazdil <dbrazdil at google.com>
Acked-by: Mark Rutland <mark.rutland at arm.com>
Signed-off-by: Will Deacon <will at kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt |  1 -
 arch/arm64/kernel/cpufeature.c                  | 10 +---------
 arch/arm64/kvm/arm.c                            |  6 +++++-
 3 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 8090130b544b..97c16aa2f53f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2469,7 +2469,6 @@
 
 			protected: nVHE-based mode with support for guests whose
 				   state is kept private from the host.
-				   Not valid if the kernel is running in EL2.
 
 			Defaults to VHE/nVHE based on hardware support. Setting
 			mode to "protected" will disable kexec and hibernation
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 42ea2bd856c6..79fac13ab2ef 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1974,15 +1974,7 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap)
 #ifdef CONFIG_KVM
 static bool is_kvm_protected_mode(const struct arm64_cpu_capabilities *entry, int __unused)
 {
-	if (kvm_get_mode() != KVM_MODE_PROTECTED)
-		return false;
-
-	if (is_kernel_in_hyp_mode()) {
-		pr_warn("Protected KVM not available with VHE\n");
-		return false;
-	}
-
-	return true;
+	return kvm_get_mode() == KVM_MODE_PROTECTED;
 }
 #endif /* CONFIG_KVM */
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 0da0f06037db..a0188144a122 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2273,7 +2273,11 @@ static int __init early_kvm_mode_cfg(char *arg)
 		return -EINVAL;
 
 	if (strcmp(arg, "protected") == 0) {
-		kvm_mode = KVM_MODE_PROTECTED;
+		if (!is_kernel_in_hyp_mode())
+			kvm_mode = KVM_MODE_PROTECTED;
+		else
+			pr_warn_once("Protected KVM not available with VHE\n");
+
 		return 0;
 	}
 
-- 
2.36.1.255.ge46751e96f-goog