Re: [PATCH 6/6] hv, mshv : Change interrupt vector for nested root partition

Wei Liu
2022-11-02T15:46:58Z

On Wed, Nov 02, 2022 at 02:00:17PM +0000, Jinank Jain wrote:
> Traditionally we have been using the HYPERVISOR_CALLBACK_VECTOR to relay
> the VMBus interrupt. But this does not work in case of nested
> hypervisor. Microsoft Hypervisor reserves 0x31 to 0x34 as the interrupt
> vector range for VMBus and thus we have to use one of the vectors from
> that range and setup the IDT accordingly.
>
> Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
> ---
> arch/x86/include/asm/idtentry.h | 2 ++
> arch/x86/include/asm/irq_vectors.h | 6 ++++++
[...]
> #if IS_ENABLED(CONFIG_ACRN_GUEST)
> diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
> index 43dcb9284208..729d19eab7f5 100644
> --- a/arch/x86/include/asm/irq_vectors.h
> +++ b/arch/x86/include/asm/irq_vectors.h
> @@ -102,6 +102,12 @@
> #if IS_ENABLED(CONFIG_HYPERV)
> #define HYPERV_REENLIGHTENMENT_VECTOR 0xee
> #define HYPERV_STIMER0_VECTOR 0xed
> +/*
> + * FIXME: Change this, once Microsoft Hypervisor changes its assumption
> + * around VMBus interrupt vector allocation for nested root partition.
> + * Or provides a better interface to detect this instead of hardcoding.
> + */
> +#define HYPERV_INTR_NESTED_VMBUS_VECTOR 0x31

I would like to hear x86 maintainers opinion on this.

Thanks,
Wei.