91f65debbe
There are 2 steps to synchronize the values of system registers from CPU state to KVM: 1. write to the values of system registers from CPU state to (index,value) list by write_cpustate_to_list; 2. write the values in (index,value) list to KVM by write_list_to_kvmstate; In step 1, the values of constant system registers are not allowed to write to (index,value) list. However, a constant system register is CONSTANT for guest but not for QEMU, which means, QEMU can set/modify the value of constant system registers that is different from phsical registers when startup. But if KVM is enabled, guest can not read the values of the system registers which QEMU set unless they can be written to (index,value) list. And why not try to write to KVM if kvm_sync is true? At the moment we call write_cpustate_to_list, all ID registers are contant, including ID_PFR1_EL1 and ID_AA64PFR0_EL1 because GIC has been initialized. Hence, let's give all ID registers a chance to write to KVM. If the write is successful, then write to (index,value) list. Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Peng Liang <liangpeng10@huawei.com> Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>