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From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Auger Eric <eric.auger@redhat.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	Jacob Pan <jacob.pan.linux@gmail.com>,
	Raj Ashok <ashok.raj@intel.com>,
	David Woodhouse <dwmw2@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	iommu@lists.linux-foundation.org, Wu Hao <hao.wu@intel.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.com>
Subject: Re: [PATCH v2 5/9] iommu/ioasid: Introduce ioasid_set private ID
Date: Tue, 8 Sep 2020 15:40:28 -0700	[thread overview]
Message-ID: <20200908154028.0ec5abba@jacob-builder> (raw)
In-Reply-To: <8fe449f7-606e-e90a-28d5-9c29cac5a9c3@redhat.com>

On Tue, 1 Sep 2020 17:38:44 +0200
Auger Eric <eric.auger@redhat.com> wrote:

> Hi Jacob,
> On 8/22/20 6:35 AM, Jacob Pan wrote:
> > When an IOASID set is used for guest SVA, each VM will acquire its
> > ioasid_set for IOASID allocations. IOASIDs within the VM must have a
> > host/physical IOASID backing, mapping between guest and host
> > IOASIDs can be non-identical. IOASID set private ID (SPID) is
> > introduced in this patch to be used as guest IOASID. However, the
> > concept of ioasid_set specific namespace is generic, thus named
> > SPID.
> > 
> > As SPID namespace is within the IOASID set, the IOASID core can
> > provide lookup services at both directions. SPIDs may not be
> > allocated when its IOASID is allocated, the mapping between SPID
> > and IOASID is usually established when a guest page table is bound
> > to a host PASID.
> > 
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> >  drivers/iommu/ioasid.c | 54
> > ++++++++++++++++++++++++++++++++++++++++++++++++++
> > include/linux/ioasid.h | 12 +++++++++++ 2 files changed, 66
> > insertions(+)
> > 
> > diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
> > index 5f31d63c75b1..c0aef38a4fde 100644
> > --- a/drivers/iommu/ioasid.c
> > +++ b/drivers/iommu/ioasid.c
> > @@ -21,6 +21,7 @@ enum ioasid_state {
> >   * struct ioasid_data - Meta data about ioasid
> >   *
> >   * @id:		Unique ID
> > + * @spid:	Private ID unique within a set
> >   * @users	Number of active users
> >   * @state	Track state of the IOASID
> >   * @set		Meta data of the set this IOASID belongs to
> > @@ -29,6 +30,7 @@ enum ioasid_state {
> >   */
> >  struct ioasid_data {
> >  	ioasid_t id;
> > +	ioasid_t spid;
> >  	struct ioasid_set *set;
> >  	refcount_t users;
> >  	enum ioasid_state state;
> > @@ -326,6 +328,58 @@ int ioasid_attach_data(ioasid_t ioasid, void
> > *data) EXPORT_SYMBOL_GPL(ioasid_attach_data);
> >  
> >  /**
> > + * ioasid_attach_spid - Attach ioasid_set private ID to an IOASID
> > + *
> > + * @ioasid: the ID to attach
> > + * @spid:   the ioasid_set private ID of @ioasid
> > + *
> > + * For IOASID that is already allocated, private ID within the set
> > can be
> > + * attached via this API. Future lookup can be done via
> > ioasid_find.  
> I would remove "For IOASID that is already allocated, private ID
> within the set can be attached via this API"
I guess it is implied. Will remove.

> > + */
> > +int ioasid_attach_spid(ioasid_t ioasid, ioasid_t spid)
> > +{
> > +	struct ioasid_data *ioasid_data;
> > +	int ret = 0;
> > +
> > +	spin_lock(&ioasid_allocator_lock);  
> We keep on saying the SPID is local to an IOASID set but we don't
> check any IOASID set contains this ioasid. It looks a bit weird to me.
We store ioasid_set inside ioasid_data when an IOASID is allocated, so
we don't need to search all the ioasid_sets. Perhaps I missed your
point?

> > +	ioasid_data = xa_load(&active_allocator->xa, ioasid);
> > +
> > +	if (!ioasid_data) {
> > +		pr_err("No IOASID entry %d to attach SPID %d\n",
> > +			ioasid, spid);
> > +		ret = -ENOENT;
> > +		goto done_unlock;
> > +	}
> > +	ioasid_data->spid = spid;  
> is there any way/need to remove an spid binding?
For guest SVA, we attach SPID as a guest PASID during bind guest page
table. Unbind does the opposite, ioasid_attach_spid() with
spid=INVALID_IOASID clears the binding.

Perhaps add more symmetric functions? i.e.
ioasid_detach_spid(ioasid_t ioasid)
ioasid_attach_spid(struct ioasid_set *set, ioasid_t ioasid)

> > +
> > +done_unlock:
> > +	spin_unlock(&ioasid_allocator_lock);
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(ioasid_attach_spid);
> > +
> > +ioasid_t ioasid_find_by_spid(struct ioasid_set *set, ioasid_t spid)
> > +{
> > +	struct ioasid_data *entry;
> > +	unsigned long index;
> > +
> > +	if (!xa_load(&ioasid_sets, set->sid)) {
> > +		pr_warn("Invalid set\n");
> > +		return INVALID_IOASID;
> > +	}
> > +
> > +	xa_for_each(&set->xa, index, entry) {
> > +		if (spid == entry->spid) {
> > +			pr_debug("Found ioasid %lu by spid %u\n",
> > index, spid);
> > +			refcount_inc(&entry->users);
> > +			return index;
> > +		}
> > +	}
> > +	return INVALID_IOASID;
> > +}
> > +EXPORT_SYMBOL_GPL(ioasid_find_by_spid);
> > +
> > +/**
> >   * ioasid_alloc - Allocate an IOASID
> >   * @set: the IOASID set
> >   * @min: the minimum ID (inclusive)
> > diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
> > index 310abe4187a3..d4b3e83672f6 100644
> > --- a/include/linux/ioasid.h
> > +++ b/include/linux/ioasid.h
> > @@ -73,6 +73,8 @@ bool ioasid_is_active(ioasid_t ioasid);
> >  
> >  void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, bool
> > (*getter)(void *)); int ioasid_attach_data(ioasid_t ioasid, void
> > *data); +int ioasid_attach_spid(ioasid_t ioasid, ioasid_t spid);
> > +ioasid_t ioasid_find_by_spid(struct ioasid_set *set, ioasid_t
> > spid); int ioasid_register_allocator(struct ioasid_allocator_ops
> > *allocator); void ioasid_unregister_allocator(struct
> > ioasid_allocator_ops *allocator); void ioasid_is_in_set(struct
> > ioasid_set *set, ioasid_t ioasid); @@ -136,5 +138,15 @@ static
> > inline int ioasid_attach_data(ioasid_t ioasid, void *data) return
> > -ENOTSUPP; }
> >  
> > +staic inline int ioasid_attach_spid(ioasid_t ioasid, ioasid_t spid)
> > +{
> > +	return -ENOTSUPP;
> > +}
> > +
> > +static inline ioasid_t ioasid_find_by_spid(struct ioasid_set *set,
> > ioasid_t spid) +{
> > +	return -ENOTSUPP;
> > +}
> > +
> >  #endif /* CONFIG_IOASID */
> >  #endif /* __LINUX_IOASID_H */
> >   
> Thanks
> 
> Eric
> 
> _______________________________________________
> iommu mailing list
> iommu@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu

[Jacob Pan]
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2020-09-08 22:38 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-22  4:35 [PATCH v2 0/9] IOASID extensions for guest SVA Jacob Pan
2020-08-22  4:35 ` [PATCH v2 1/9] docs: Document IO Address Space ID (IOASID) APIs Jacob Pan
2020-08-23  7:05   ` Lu Baolu
2020-08-28 17:01     ` Jacob Pan
2020-08-24 10:32   ` Jean-Philippe Brucker
2020-08-27 16:21     ` Auger Eric
2020-09-01 16:56       ` Jacob Pan
2020-09-07  8:03         ` Auger Eric
2020-09-08 17:29           ` Jacob Pan
2020-08-28 22:24     ` Jacob Pan
2020-08-22  4:35 ` [PATCH v2 2/9] iommu/ioasid: Rename ioasid_set_data() Jacob Pan
2020-08-24 18:29   ` Jean-Philippe Brucker
2020-09-01 11:51   ` Auger Eric
2020-08-22  4:35 ` [PATCH v2 3/9] iommu/ioasid: Introduce ioasid_set APIs Jacob Pan
2020-08-22 12:53   ` kernel test robot
2020-08-24  2:24   ` Lu Baolu
2020-09-01 21:28     ` Jacob Pan
2020-09-02  2:39       ` Lu Baolu
2020-08-24 18:28   ` Jean-Philippe Brucker
2020-08-24 18:30     ` Randy Dunlap
2020-09-02 21:46       ` Jacob Pan
2020-08-24 18:34     ` Randy Dunlap
2020-09-02 21:47       ` Jacob Pan
2020-09-02 21:44     ` Jacob Pan
2020-09-01 11:51   ` Auger Eric
2020-09-03 21:07     ` Jacob Pan
2020-09-07  8:04       ` Auger Eric
2020-08-22  4:35 ` [PATCH v2 4/9] iommu/ioasid: Add reference couting functions Jacob Pan
2020-08-24  2:26   ` Lu Baolu
2020-08-25 10:20     ` Jean-Philippe Brucker
2020-08-25 10:19   ` Jean-Philippe Brucker
2020-09-08 20:30     ` Jacob Pan
2020-09-01 12:13   ` Auger Eric
2020-09-08 20:49     ` Jacob Pan
2020-09-24 18:29   ` Shameerali Kolothum Thodi
2020-08-22  4:35 ` [PATCH v2 5/9] iommu/ioasid: Introduce ioasid_set private ID Jacob Pan
2020-08-22  8:36   ` kernel test robot
2020-08-22  9:03   ` kernel test robot
2020-08-25 10:22   ` Jean-Philippe Brucker
2020-09-08 22:19     ` Jacob Pan
2020-09-01 15:38   ` Auger Eric
2020-09-08 22:40     ` Jacob Pan [this message]
2020-09-10  9:18       ` Auger Eric
2020-08-22  4:35 ` [PATCH v2 6/9] iommu/ioasid: Introduce notification APIs Jacob Pan
2020-08-25 10:26   ` Jean-Philippe Brucker
2020-09-09 20:37     ` Jacob Pan
2020-09-01 16:49   ` Auger Eric
2020-09-09 22:58     ` Jacob Pan
2020-09-10  8:59       ` Auger Eric
2020-08-22  4:35 ` [PATCH v2 7/9] iommu/vt-d: Listen to IOASID notifications Jacob Pan
2020-09-01 17:03   ` Auger Eric
2020-09-10  4:54     ` Jacob Pan
2020-08-22  4:35 ` [PATCH v2 8/9] iommu/vt-d: Send IOASID bind/unbind notifications Jacob Pan
2020-08-22  4:35 ` [PATCH v2 9/9] iommu/vt-d: Store guest PASID during bind Jacob Pan
2020-09-01 17:08   ` Auger Eric
2020-09-10 17:12     ` Jacob Pan

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