Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface

From	Joerg Roedel <joro@8bytes.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface
Date	2017-08-23 14:10 +0200
Message-ID	<uhCDV-nu-47@gated-at.bofh.it> (permalink)
References	<ufsyZ-4YZ-7@gated-at.bofh.it> <ufu7L-67i-9@gated-at.bofh.it> <ufuhr-6aR-1@gated-at.bofh.it> <ufur8-6eX-19@gated-at.bofh.it> <ufuUa-6IK-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Thu, Aug 17, 2017 at 05:22:20PM +0200, Joerg Roedel wrote:
> What I absolutly don't want is that the whole explicit TLB flushing
> of the IOMMU-API (as introduced in this patch-set) is considered some
> optional part of the API, as it would be when I just introduce _async
> versions of map/unmap/map_sg.

Okay, forget that :)

The discussions I had around this interface made me change it a little
bit in the version 2 of the patch-set which I will post soon.

I thought a bit more about the iommu_map() code-path. It really doesn't
make any sense to remove the tlb-sync requirement from it, because in
almost all cases the hardware doesn't require any flushes after a map
operation anyway. And in the rare cases where it does - because the
hardware is emulated and slow - the iommu-driver can handle
that by doing a flush in its iommu_ops->map() call-back.

So I removed the iommu_map_sync() and iommu_map_sg_sync() functions from
this series. With those changes it also doesn't make sense anymore
to have different tlb-sync semantics between iommu_map() and
iommu_unmap(). So I ended up introducing a new iommu_unmap_fast()
function which can unmap ranges and return with dirty io-tlbs.

This makes the extension of couse look somewhat optional, which I tried
to avoid, but I hope the '_fast' part of the name is enough motivation for
iommu-api users to look into ways to use it in their code.

Regards,

	Joerg

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface Joerg Roedel <joro@8bytes.org> - 2017-08-17 15:10 +0200
  [PATCH 03/13] vfio/type1: Use sychronized interface of the IOMMU-API Joerg Roedel <joro@8bytes.org> - 2017-08-17 15:10 +0200
  Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface Alex Williamson <alex.williamson@redhat.com> - 2017-08-17 16:40 +0200
    Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface Joerg Roedel <joro@8bytes.org> - 2017-08-17 16:50 +0200
      Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface Alex Williamson <alex.williamson@redhat.com> - 2017-08-17 17:00 +0200
        Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface Joerg Roedel <joro@8bytes.org> - 2017-08-17 17:30 +0200
          Re: [PATCH 00/13] Introduce IOMMU-API TLB Flushing Interface Joerg Roedel <joro@8bytes.org> - 2017-08-23 14:10 +0200

csiph-web