[PATCH 1/2] KVM: Add KVM_EXIT_RESET to user space API header

[Alexander Graf]

On 25.11.2013, at 16:49, Anup Patel <anup.patel at linaro.org> wrote:

> Currently, we don't have an exit reason for VM reset emulation
> in user space hence this patch adds exit reason KVM_EXIT_RESET
> for this purpose.
> 
> This newly added KVM_EXIT_RESET will be used by KVM arm/arm64
> in-kernel PSCI support to reset VMs.
> 
> Signed-off-by: Anup Patel <anup.patel at linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
> ---
> include/uapi/linux/kvm.h |    1 +
> 1 file changed, 1 insertion(+)
> 
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 902f124..64a04cc 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -171,6 +171,7 @@ struct kvm_pit_config {
> #define KVM_EXIT_WATCHDOG         21
> #define KVM_EXIT_S390_TSCH        22
> #define KVM_EXIT_EPR              23
> +#define KVM_EXIT_RESET            24

I have to admit that I'm not particularly happy with the exit name. It's not obvious from the name under which circumstances it gets triggered. Does it get triggered when a core level reset happens? Does it get triggered when a system level reset happened? When the guest requests one?

I know what it does, but I find the name too generic for what it is. What you're really doing is introduce a new communication channel in parallel to MMIO / PIO / HCALL which is only used for system level reset / shutdown today.

Can we treat it as such? Could you please make this a common exit number that's called something like

  KVM_EXIT_SYSTEM_EVENT

with a parameter that can either be TRIGGER_SHUTDOWN or TRIGGER_RESET.

That way it's obvious what's going on and people don't get confused.


Alex