Re: [PATCH RFC PREVIEW 1/6] iommu/vt-d: Separate page request queue from SVM

[Baolu Lu]

On 2024/9/4 17:12, Joel Granados wrote:
> On Mon, Aug 26, 2024 at 09:09:14PM +0800, Baolu Lu wrote:
> > On 2024/8/26 19:40, Klaus Jensen wrote:
> > > From: Joel Granados<j.granados@xxxxxxxxxxx>
> > >
> > > IO page faults are no longer dependent on CONFIG_INTEL_IOMMU_SVM. Move
> > > all Page Request Queue (PRQ) functions that handle prq events to a new
> > > file in drivers/iommu/intel/prq.c. The page_req_des struct is made
> > > available in drivers/iommu/intel/iommu.h.
> > >
> > > No functional changes are intended. This is a preparation patch to
> > > enable the use of IO page faults outside the SVM and nested use cases.
> > >
> > > Signed-off-by: Joel Granados<j.granados@xxxxxxxxxxx>
> > > ---
> > >    drivers/iommu/intel/Makefile |   2 +-
> > >    drivers/iommu/intel/iommu.c  |  18 +--
> > >    drivers/iommu/intel/iommu.h  |  40 +++++-
> > >    drivers/iommu/intel/prq.c    | 290 ++++++++++++++++++++++++++++++++++++++++
> > >    drivers/iommu/intel/svm.c    | 308 -------------------------------------------
> > >    5 files changed, 331 insertions(+), 327 deletions(-)
> > >
> > > diff --git a/drivers/iommu/intel/Makefile b/drivers/iommu/intel/Makefile
> > > index c8beb0281559..d3bb0798092d 100644
> > > --- a/drivers/iommu/intel/Makefile
> > > +++ b/drivers/iommu/intel/Makefile
> > > @@ -1,6 +1,6 @@
> > >    # SPDX-License-Identifier: GPL-2.0
> > >    obj-$(CONFIG_DMAR_TABLE) += dmar.o
> > > -obj-$(CONFIG_INTEL_IOMMU) += iommu.o pasid.o nested.o cache.o
> > > +obj-$(CONFIG_INTEL_IOMMU) += iommu.o pasid.o nested.o cache.o prq.o
> > >    obj-$(CONFIG_DMAR_TABLE) += trace.o cap_audit.o
> > >    obj-$(CONFIG_DMAR_PERF) += perf.o
> > >    obj-$(CONFIG_INTEL_IOMMU_DEBUGFS) += debugfs.o
> > Thanks for the patch! Now that IOPF is separate from SVA, the Kconfig
> > needs to be updated accordingly.
> >
> > diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
> > index f52fb39c968e..2888671c9278 100644
> > --- a/drivers/iommu/intel/Kconfig
> > +++ b/drivers/iommu/intel/Kconfig
> > @@ -15,6 +15,7 @@ config INTEL_IOMMU
> >           select DMA_OPS
> >           select IOMMU_API
> >           select IOMMU_IOVA
> > +       select IOMMU_IOPF
> This will force IOMMU_IOPF when INTEL_IOMMU is selected. You do this in
> order to use IOPF if available, but it wont conflict with Intel IOMMU's
> that do not support IOPF. right?

Intel VT-d includes a bit in the capability registers that indicates
whether PRI is supported by the hardware. Therefore, there should be no
conflict.

Thanks,
baolu