Re: [Question] some questions about vmx

Vitaly Kuznetsov
2020-02-07T09:08:53Z

linmiaohe <linmiaohe@huawei.com> writes:

> Hi:
> Vitaly Kuznetsov <vkuznets@redhat.com> writes:
>>linmiaohe <linmiaohe@huawei.com> writes:
>>
>>> About nWMX.
>>> When nested_vmx_handle_enlightened_vmptrld() return 0, it do not
>>> inject any exception or set rflags to Indicate VMLAUNCH instruction
>>> failed and skip this instruction. This would cause nested_vmx_run()
>>
>>Yes, it seems it can.
>>
>>nested_vmx_handle_enlightened_vmptrld() has two possible places where it can fail:
>>
>>kvm_vcpu_map() -- meaning that the guest passed some invalid GPA.
>>revision id check -- meaning that the supplied eVMCS is unsupported/garbage.
>>
>>I think the right behavior would be to nested_vmx_failInvalid() in both these cases. We can also check what genuing Hyper-V does.
>>
>
> Many thanks for your reply. I think this would be a problem too. And would you like to fix this potential problem? I have no idea
> how to fix this correctly...

Yes,

let me check what happens on Hyper-V and I'll send a patch. The problem
should not be that severe as it only affect misbehaving L1 hypervisors.

--
Vitaly