Kernel patch cases qemu live migration failed.

[张东旭]

I'm so sorry for disturbing you.

When I apply this kernel patch：KVM: arm64/sve: System register context switch and access support

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/kvm/sys_regs.c?id=73433762fcaeb9d59e84d299021c6b15466c96dd

qemu live migration will failed with messages：

              ​qemu-kvm: Invalid value 233 expecting positive value <= 232

              qemu-kvm: Failed to load cpu:cpreg_vmstate_array_len

New version kernel  exclude ID_AA64ZFR0_EL1 register when host not support SVE feature,

so qemu ioctl kvm(KVM_GET_REG_LIST) will not contain ID_AA64ZFR0_EL1 register.

I'm using CentOS Linux kernel, old kernel version：4.18.0-80.11.el8 (migration source)

     new kernel version：4.18.0-147.5.el8 (migration destination)

CentOS linux kernel version 4.18.0-111.el8 applied this patch. So 4.18.0-147.5.el8 also applied this patch.

Migration source and destination hosts have the same hardware, just kernel version is different, 

and the hardware on either side of the migration not support SVE.

 

Is there some good suggestions，which can make sure old version kernel live migration to new version kernel with qemu?

Thanks a lot.