[PATCH v3 2/4] KVM: arm64: Inject UNDEF for a register trap without 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. Also inject an
undefined instruction exception in the guest, similar to other unhandled
register accesses.

Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
---
 arch/arm64/kvm/sys_regs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c8fd7c6a12a1..88a57ca36d96 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -4668,7 +4668,10 @@ 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) {
+		bad_trap(vcpu, params, r, "register access");
+		return;
+	}
 
 	/* Skip instruction if instructed so */
 	if (likely(r->access(vcpu, params, r)))
-- 
2.52.0