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>
QEMU does not support disable/enable CPU features in AArch64 for now.
This patch series add support for CPU features in AArch64.
Firstly, we change the isar struct in ARMCPU to an array for
convenience. Secondly, we add support to configure CPU feautres in
AArch64 and make sure that the ID registers can be synchronized to KVM
so that guest can read the value we configure. Thirdly, we add a
mechanism to solve the dependency relationship of some CPU features.
Last, we add a KVM_CAP_ARM_CPU_FEATURE to check whether KVM supports to
set CPU features in AArch64.
Also export CPU features to the result of qmp query-cpu-model-expansion
so that libvirt can get the supported CPU features.
Update the ID fields to ARMv8.6 and add some CPU features according to
the new ID fields.
With related KVM patch set[1], we can disable/enable CPU features in
AArch64.
[1] https://patchwork.kernel.org/cover/11711693/
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
