[PATCH v1] KVM: arm64: Move pkvm_selftests() after all CPUs have initialized EL2

[Vincent Donnefort]

init_subsystems() installs the hyp vector on all CPUs. By running
pkvm_selftests() in init_hyp_mode(), there's a risk for a migration to a
CPU where the hyp stub is still in place which would fail to run one of
the HVCs necessary for the selftest.

While init_subsystems() is the earliest we can call pkvm_selftests(),
move it to finalize_pkvm() to avoid having to export the selftest
function out of pkvm.c.

Fixes: bd93068340e9 ("KVM: arm64: Add selftests for the pKVM heap allocator")
Reported-by: Fuad Tabba <fuad.tabba at linux.dev>
Signed-off-by: Vincent Donnefort <vdonnefort at google.com>
---
 arch/arm64/include/asm/kvm_pkvm.h | 1 -
 arch/arm64/kvm/arm.c              | 2 --
 arch/arm64/kvm/pkvm.c             | 4 +++-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h
index e7562770e7cb..fd042d2b5462 100644
--- a/arch/arm64/include/asm/kvm_pkvm.h
+++ b/arch/arm64/include/asm/kvm_pkvm.h
@@ -17,7 +17,6 @@
 
 #define HYP_MEMBLOCK_REGIONS 128
 
-void pkvm_selftests(void);
 int pkvm_init_host_vm(struct kvm *kvm);
 int pkvm_create_hyp_vm(struct kvm *kvm);
 bool pkvm_hyp_vm_is_created(struct kvm *kvm);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index d593ba928093..93eac8959865 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -3109,8 +3109,6 @@ static int __init init_hyp_mode(void)
 			kvm_err("Failed to init hyp memory protection\n");
 			goto out_err;
 		}
-
-		pkvm_selftests();
 	}
 
 	return 0;
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 380dfb1db0be..016997288fd2 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -333,7 +333,7 @@ static int __init pkvm_drop_host_privileges(void)
 	return ret;
 }
 
-void __init pkvm_selftests(void)
+static void __init pkvm_selftests(void)
 {
 #ifdef CONFIG_NVHE_EL2_DEBUG
 	int ret = pkvm_call_hyp_req(__pkvm_hyp_alloc_selftest);
@@ -387,6 +387,8 @@ static int __init finalize_pkvm(void)
 	if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised())
 		return 0;
 
+	pkvm_selftests();
+
 	/*
 	 * Exclude HYP sections from kmemleak so that they don't get peeked
 	 * at, which would end badly once inaccessible.

base-commit: dd0bc00e3e9201fd49b62ff9cc07890c89003afe
-- 
2.56.0.176.g3575e65682-goog