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>

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 4048934..2e90371 100644 (file)
--- 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 */