From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
"eric.auger@redhat.com" <eric.auger@redhat.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"Raj, Ashok" <ashok.raj@intel.com>,
"Tian, Jun J" <jun.j.tian@intel.com>,
"Sun, Yi Y" <yi.y.sun@intel.com>,
"jean-philippe.brucker@arm.com" <jean-philippe.brucker@arm.com>,
"peterx@redhat.com" <peterx@redhat.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
jacob.jun.pan@linux.intel.com
Subject: Re: [RFC v3 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
Date: Thu, 6 Feb 2020 10:12:53 -0800 [thread overview]
Message-ID: <20200206101253.7fb43e07@jacob-builder> (raw)
In-Reply-To: <A2975661238FB949B60364EF0F2C25743A1993E8@SHSMSX104.ccr.corp.intel.com>
Hi Alex,
On Fri, 31 Jan 2020 12:41:06 +0000
"Liu, Yi L" <yi.l.liu@intel.com> wrote:
> > > +static int vfio_iommu_type1_pasid_free(struct vfio_iommu *iommu,
> > > + unsigned int pasid)
> > > +{
> > > + struct vfio_mm *vmm = iommu->vmm;
> > > + int ret = 0;
> > > +
> > > + mutex_lock(&iommu->lock);
> > > + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
> >
> > But we could have been IOMMU backed when the pasid was allocated,
> > did we just leak something? In fact, I didn't spot anything in
> > this series that handles a container with pasids allocated losing
> > iommu backing. I'd think we want to release all pasids when that
> > happens since permission for the user to hold pasids goes along
> > with having an iommu backed device.
>
> oh, yes. If a container lose iommu backend, then needs to reclaim the
> allocated PASIDs. right? I'll add it. :-)
>
> > Also, do we want _free() paths that can fail?
>
> I remember we discussed if a _free() path can fail, I think we agreed
> to let _free() path always success. :-)
Just to add some details. We introduced IOASID notifier such that when
VFIO frees a PASID, consumers such as IOMMU, can do the cleanup
therefore ensure free always succeeds.
https://www.spinics.net/lists/kernel/msg3349928.html
https://www.spinics.net/lists/kernel/msg3349930.html
This was not in my v9 set as I was considering some race conditions
w.r.t. registering notifier, gets notifications, and free call. I will
post it in v10.
Thanks,
Jacob
next prev parent reply other threads:[~2020-02-06 18:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 12:11 [RFC v3 0/8] vfio: expose virtual Shared Virtual Addressing to VMs Liu, Yi L
2020-01-29 12:11 ` [RFC v3 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free) Liu, Yi L
2020-01-29 23:55 ` Alex Williamson
2020-01-31 12:41 ` Liu, Yi L
2020-02-06 9:41 ` Liu, Yi L
2020-02-06 18:12 ` Jacob Pan [this message]
2020-02-18 5:07 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 2/8] vfio/type1: Make per-application (VM) PASID quota tunable Liu, Yi L
2020-01-29 23:56 ` Alex Williamson
2020-02-05 6:23 ` Liu, Yi L
2020-02-07 19:43 ` Jacob Pan
2020-02-08 8:46 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 3/8] vfio: Reclaim PASIDs when application is down Liu, Yi L
2020-01-29 23:56 ` Alex Williamson
2020-01-31 12:42 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 4/8] vfio/type1: Add VFIO_NESTING_GET_IOMMU_UAPI_VERSION Liu, Yi L
2020-01-29 23:56 ` Alex Williamson
2020-01-31 13:04 ` Liu, Yi L
2020-02-03 18:00 ` Alex Williamson
2020-02-05 6:19 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 5/8] vfio/type1: Report 1st-level/stage-1 page table format to userspace Liu, Yi L
2020-01-29 12:11 ` [RFC v3 6/8] vfio/type1: Bind guest page tables to host Liu, Yi L
2020-01-29 12:11 ` [RFC v3 7/8] vfio/type1: Add VFIO_IOMMU_CACHE_INVALIDATE Liu, Yi L
2020-01-29 12:11 ` [RFC v3 8/8] vfio/type1: Add vSVA support for IOMMU-backed mdevs Liu, Yi L
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