Re: [PATCH 09/18] iommu/vt-d: Enlightened PASID allocation

From: Andriy Shevchenko
Date: Tue Apr 09 2019 - 06:09:07 EST


On Mon, Apr 08, 2019 at 04:59:24PM -0700, Jacob Pan wrote:
> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>
> If Intel IOMMU runs in caching mode, a.k.a. virtual IOMMU, the
> IOMMU driver should rely on the emulation software to allocate
> and free PASID IDs. The Intel vt-d spec revision 3.0 defines a
> register set to support this. This includes a capability register,
> a virtual command register and a virtual response register. Refer
> to section 10.4.42, 10.4.43, 10.4.44 for more information.
>
> This patch adds the enlightened PASID allocation/free interfaces
> via the virtual command register.

> + pr_debug("vcmd alloc pasid\n");

Perhaps tracepoints should be in use?
OTOH we have function tracer, so, this message in any case is a noise.
And this is applicable to other similar cases.

--
With Best Regards,
Andy Shevchenko