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From:   "Liu, Yi L" <yi.l.liu@intel.com>
To:     Jean-Philippe Brucker <jean-philippe@linaro.org>
CC:     "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
        "eric.auger@redhat.com" <eric.auger@redhat.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        "jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.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>,
        "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>,
        "Wu, Hao" <hao.wu@intel.com>
Subject: RE: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
Thread-Topic: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
Thread-Index: AQHWAEUbC4GB74LMekup8jIcF6WIFqhlZUwAgAH1tzD//4hGgIAAhuqA
Date:   Fri, 3 Apr 2020 12:44:51 +0000
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> From: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Sent: Friday, April 3, 2020 8:40 PM
> Subject: Re: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
> 
> On Fri, Apr 03, 2020 at 11:56:09AM +0000, Liu, Yi L wrote:
> > > >  /**
> > > > + * VFIO_MM objects - create, release, get, put, search
> > > > + * Caller of the function should have held vfio.vfio_mm_lock.
> > > > + */
> > > > +static struct vfio_mm *vfio_create_mm(struct mm_struct *mm) {
> > > > +	struct vfio_mm *vmm;
> > > > +	struct vfio_mm_token *token;
> > > > +	int ret = 0;
> > > > +
> > > > +	vmm = kzalloc(sizeof(*vmm), GFP_KERNEL);
> > > > +	if (!vmm)
> > > > +		return ERR_PTR(-ENOMEM);
> > > > +
> > > > +	/* Per mm IOASID set used for quota control and group operations */
> > > > +	ret = ioasid_alloc_set((struct ioasid_set *) mm,
> > >
> > > Hmm, either we need to change the token of ioasid_alloc_set() to
> > > "void *", or pass an actual ioasid_set struct, but this cast doesn't
> > > look good :)
> > >
> > > As I commented on the IOASID series, I think we could embed a struct
> > > ioasid_set into vfio_mm, pass that struct to all other ioasid_*
> > > functions, and get rid of ioasid_sid.
> >
> > I think change to "void *" is better as we needs the token to ensure
> > all threads within a single VM share the same ioasid_set.
> 
> Don't they share the same vfio_mm?

that's right. then both works well for me.

Regards,
Yi Liu