Re: [PATCH] intel_iommu: Optimize out some unnecessary UNMAP calls

[Jason Gunthorpe]

On Fri, May 26, 2023 at 08:44:29AM +0000, Liu, Yi L wrote:

> > > >> In fact, the other purpose of this patch is to eliminate noisy error
> > > >> log when we work with IOMMUFD. It looks the duplicate UNMAP call will
> > > >> fail with IOMMUFD while always succeed with legacy container. This
> > > >> behavior difference lead to below error log for IOMMUFD:
> > 
> > A dumb question, should IOMMUFD stick the same behaviour with legacy 
> > container?
> 
> May need to hear from JasonG. 😊 Should IOMMU_IOAS_UNMAP return error or
> success if the iova is not found?

The native iommufd functions will return failure if they could not
unmap anything.

Otherwise they return the number of consecutive bytes unmapped.

The VFIO emulation functions should do whatever VFIO does, is there a
mistake there?

Jason