arm64: KVM: Fix guest dead loop when register accessor returns false

Currently emulate_cp will return 0 (Handled) no matter what the accessor
returns. If register accessor returns false, it will not skip current PC
while emulate_cp return handled. Then guest will stuck in a dead loop.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 4048934bb3a5..2e90371cfb37 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1007,10 +1007,9 @@ static int emulate_cp(struct kvm_vcpu *vcpu,
                 if (likely(r->access(vcpu, params, r))) {
                         /* Skip instruction, since it was emulated */
                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+                        /* Handled */
+                        return 0;
                 }
-
-                /* Handled */
-                return 0;
         }
 
         /* Not handled */