Re: [PATCH v2 2/3] KVM: selftests: Extend @shape to allow creation of VM without in-kernel APIC

[Manali Shukla <manali.shukla@amd.com>]

Hi Sean,

On 4/1/2024 10:45 PM, Sean Christopherson wrote:
> On Mon, Apr 01, 2024, Manali Shukla wrote:
>> Currently, all the VMs are created with in-kernel APIC support in KVM
>> selftests because KVM_CREATE_IRQCHIP ioctl is called by default from
>> kvm_arch_vm_post_create().
>>
>> Carve out space in the @shape passed to the various VM creation helpers to
>> allow using the shape to control creation of a VM without in-kernel APIC
>> support or with in-kernel APIC support.
>>
>> This is a preparatory patch to create a vm without in-kernel APIC support for
>> the KVM_X86_DISABLE_EXITS_HLT test.
> 
> Ugh, when I suggested creating a VM without an in-kernel APIC as away to easily
> test that HLT doesn't exit, I wasn't thinking about the side effects of creating
> a runnable VM without an in-kernel APIC.  The other downside is that practically
> no one uses a userspace local APIC these days, i.e. the selftest isn't a great
> representation of real world setups.
> 
> Given that KVM already provides vcpu->stat.halt_exits, using a stats FD for
> verifying exiting behavior is probably a better option.  The other check that
> could be added would be to verify that mp_state is always RUNNABLE (which is a
> bug/gap in KVM as migrating a vCPU that was halted in the guest won't resume in
> a halted state on the target).
 
Sure. I will work on it.

- Manali