From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: iommu@lists.linux-foundation.org,
LKML <linux-kernel@vger.kernel.org>,
"Lu Baolu" <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
"Yi Liu" <yi.l.liu@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
Raj Ashok <ashok.raj@intel.com>,
"Christoph Hellwig" <hch@infradead.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Jonathan Cameron <jic23@kernel.org>,
Eric Auger <eric.auger@redhat.com>,
jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH 3/3] iommu/uapi: Add helper function for size lookup
Date: Fri, 31 Jan 2020 09:56:21 -0800 [thread overview]
Message-ID: <20200131095621.6acec2fc@jacob-builder> (raw)
In-Reply-To: <20200129144046.3f91e4c1@w520.home>
On Wed, 29 Jan 2020 14:40:46 -0700
Alex Williamson <alex.williamson@redhat.com> wrote:
> On Tue, 28 Jan 2020 22:02:04 -0800
> Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:
>
> > IOMMU UAPI can be extended in the future by adding new
> > fields at the end of each user data structure. Since we use
> > a unified UAPI version for compatibility checking, a lookup
> > function is needed to find the correct user data size to copy
> > from user.
> >
> > This patch adds a helper function based on a 2D lookup with
> > version and type as input arguments.
> >
> > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> > drivers/iommu/iommu.c | 22 ++++++++++++++++++++++
> > include/linux/iommu.h | 6 ++++++
> > 2 files changed, 28 insertions(+)
> >
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index 7dd51c5d2ba1..9e5de9abebdf 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -1696,6 +1696,28 @@ int iommu_sva_unbind_gpasid(struct
> > iommu_domain *domain, struct device *dev, }
> > EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
> >
> > +
> > +/**
> > + * Maintain a UAPI version to user data structure size lookup for
> > each
> > + * API function types we support. e.g. bind guest pasid, cache
> > invalidation.
> > + * As data structures being extended with new members, the
> > offsetofend()
> > + * will identify the new sizes.
> > + */
> > +const static int
> > iommu_uapi_data_size[NR_IOMMU_UAPI_TYPE][IOMMU_UAPI_VERSION] = {
> > + /* IOMMU_UAPI_BIND_GPASID */
> > + {offsetofend(struct iommu_gpasid_bind_data, vtd)},
> > + /* IOMMU_UAPI_CACHE_INVAL */
> > + {offsetofend(struct iommu_cache_invalidate_info,
> > addr_info)},
> > + /* IOMMU_UAPI_PAGE_RESP */
> > + {offsetofend(struct iommu_page_response, code)},
> > +};
> > +
> > +int iommu_uapi_get_data_size(int type, int version)
> > +{
>
> Seems like this is asking for a bounds check,
>
> if (type >= NR_IOMMU_UAPI_TYPE || version > IOMMU_UAPI_VERSION)
> return -EINVAL;
>
yes, agreed.
> If we add new types in future versions, I assume we'd back fill the
> table with -EINVAL as well (rather than zero). Thanks,
>
right, if the array increase due to new types, the older version with
the new type should be filled with -EINVAL.
Let me document this in the rules of extensions.
> Alex
>
> > + return iommu_uapi_data_size[type][version - 1];
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_uapi_get_data_size);
> > +
> > static void __iommu_detach_device(struct iommu_domain *domain,
> > struct device *dev)
> > {
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 9718c109ea0a..416fe02160ba 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -500,6 +500,7 @@ extern int iommu_report_device_fault(struct
> > device *dev, struct iommu_fault_event *evt);
> > extern int iommu_page_response(struct device *dev,
> > struct iommu_page_response *msg);
> > +extern int iommu_uapi_get_data_size(int type, int version);
> >
> > extern int iommu_group_id(struct iommu_group *group);
> > extern struct iommu_group *iommu_group_get_for_dev(struct device
> > *dev); @@ -885,6 +886,11 @@ static inline int
> > iommu_page_response(struct device *dev, return -ENODEV;
> > }
> >
> > +static int iommu_uapi_get_data_size(int type, int version)
> > +{
> > + return -ENODEV;
> > +}
> > +
> > static inline int iommu_group_id(struct iommu_group *group)
> > {
> > return -ENODEV;
>
[Jacob Pan]
prev parent reply other threads:[~2020-01-31 17:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 6:02 [PATCH 0/3] IOMMU user API enhancement Jacob Pan
2020-01-29 6:02 ` [PATCH 1/3] iommu/uapi: Define uapi version and capabilities Jacob Pan
2020-02-06 10:14 ` Auger Eric
2020-02-06 18:22 ` Jacob Pan
2020-01-29 6:02 ` [PATCH 2/3] iommu/uapi: Use unified UAPI version Jacob Pan
2020-01-29 6:02 ` [PATCH 3/3] iommu/uapi: Add helper function for size lookup Jacob Pan
2020-01-29 21:40 ` Alex Williamson
2020-01-29 22:19 ` Alex Williamson
2020-01-31 19:51 ` Jacob Pan
2020-01-31 23:51 ` Jacob Pan
2020-02-03 18:27 ` Alex Williamson
2020-02-03 20:41 ` Jacob Pan
2020-02-03 21:12 ` Alex Williamson
2020-02-03 22:41 ` Jacob Pan
2020-02-06 10:14 ` Auger Eric
2020-02-07 8:47 ` Jean-Philippe Brucker
2020-01-31 17:56 ` Jacob Pan [this message]
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