[PATCH v2 4/4] KVM: arm64: pkvm: Avoid trapping on HVC_RESET_VECTORS

[Vincent Donnefort]

pKVM prevents the reset of the hypervisor vector and as a consequence,
kvm_hyp_initialized can never be reset. Add a fast-path for this case to
skip unnecessary HVCs on the CPU hotplug and PM path.

Signed-off-by: Vincent Donnefort <vdonnefort at google.com>
---
 arch/arm64/kvm/arm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 4c4e2fb7b660..3d7199a87ca9 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2248,8 +2248,13 @@ static void cpu_init_hyp_mode(void)
 
 static int cpu_hyp_reset(void)
 {
-	if (!is_kernel_in_hyp_mode())
+	if (!is_kernel_in_hyp_mode()) {
+		/* pKVM fast-path */
+		if (is_protected_kvm_enabled() && __this_cpu_read(kvm_hyp_initialized))
+			return -EPERM;
+
 		return __hyp_reset_vectors() ? -EPERM : 0;
+	}
 
 	return 0;
 }
-- 
2.56.0.257.gf7497c7d27-goog