[PATCH v2 2/4] KVM: arm64: Print register encoding if there's no accessor

[Alexandru Elisei]

Configuring a register trap without specifying an accessor function is
abviously a bug. Instead of calling die() when that happens, let's be a bit
more helpful and print the register encoding and kill the virtual machine
instead.

Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
---
 arch/arm64/kvm/sys_regs.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c8fd7c6a12a1..d669f6fef177 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -4668,7 +4668,13 @@ static void perform_access(struct kvm_vcpu *vcpu,
 	 * that we don't know how to handle. This certainly qualifies
 	 * as a gross bug that should be fixed right away.
 	 */
-	BUG_ON(!r->access);
+	if (!r->access) {
+		KVM_BUG(1, vcpu->kvm,
+			"Unexpected access to register: { Op0(%2u), Op1(%2u), CRn(%2u), CRm(%2u), Op2(%2u) } (%s)",
+			params->Op0, params->Op1, params->CRn, params->CRm, params->Op2,
+			str_write_read(params->is_write));
+		return;
+	}
 
 	/* Skip instruction if instructed so */
 	if (likely(r->access(vcpu, params, r)))
-- 
2.52.0