Re: [PATCH 5/8] x86/mmu: Add mm-based PASID refcounting

[Thomas Gleixner]

On Mon, Sep 20 2021 at 19:23, Fenghua Yu wrote:
>  
> +#ifdef CONFIG_INTEL_IOMMU_SVM
> +void pasid_put(struct task_struct *tsk, struct mm_struct *mm);
> +#else
> +static inline void pasid_put(struct task_struct *tsk, struct mm_struct *mm) { }
> +#endif

This code is again defining that PASID is entirely restricted to
INTEL. It's true, that no other vendor supports this, but PASID is
a non-vendor specific concept.

Sticking this into INTEL code means that any other PASID implementation
has to rip it out again from INTEL code and make it a run time property.

The refcounting issue should be the same for all PASID mechanisms which
attach PASID to a mm. What's INTEL specific about that?

So can we pretty please do that correct right away?

Thanks,

        tglx