Hi Dongjiu Geng,
On 09/06/18 13:40, Marc Zyngier wrote:
> On Fri, 08 Jun 2018 20:48:40 +0100, Dongjiu Geng wrote:
>> For the migrating VMs, user space may need to know the exception
>> state. For example, in the machine A, KVM make an SError pending,
>> when migrate to B, KVM also needs to pend an SError.
>>
>> This new IOCTL exports user-invisible states related to SError.
>> Together with appropriate user space changes, user space can get/set
>> the SError exception state to do migrate/snapshot/suspend.
>> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>> index 04b3256..df4faee 100644
>> --- a/arch/arm64/include/uapi/asm/kvm.h
>> +++ b/arch/arm64/include/uapi/asm/kvm.h
>> @@ -153,6 +154,18 @@ struct kvm_sync_regs {
>> struct kvm_arch_memory_slot {
>> };
>>
>> +/* for KVM_GET/SET_VCPU_EVENTS */
>> +struct kvm_vcpu_events {
>> + struct {
>> + __u8 serror_pending;
>> + __u8 serror_has_esr;
>> + /* Align it to 8 bytes */
>> + __u8 pad[6];
>> + __u64 serror_esr;
>> + } exception;
>> + __u32 reserved[12];
>> +};
>> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
>> index 56a0260..4426915 100644
>> --- a/arch/arm64/kvm/guest.c
>> +++ b/arch/arm64/kvm/guest.c
>> +int kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
>> + struct kvm_vcpu_events *events)
>> +{
>> + bool serror_pending = events->exception.serror_pending;
>> + bool has_esr = events->exception.serror_has_esr;
>> +
>> + if (serror_pending && has_esr) {
>> + if (!cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
>> + return -EINVAL;
>> +
>> + kvm_set_sei_esr(vcpu, events->exception.serror_esr);
>> + } else if (serror_pending) {
>> + kvm_inject_vabt(vcpu);
>> + }
>> +
>> + return 0;
>
> There was an earlier request to check that all the padding is set to
> zero. I still think this makes sense.
I agree, not just the exception.padding[], but reserved[] too.
Thanks,
James
