linux-kernel - RE: [PATCH v7 2/6] vfio/type1: Check reserve region conflict and update iova list

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Date:   Thu, 4 Jul 2019 22:06:23 +0000
From:   Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
To:     Alex Williamson <alex.williamson@...hat.com>
CC:     "eric.auger@...hat.com" <eric.auger@...hat.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        Linuxarm <linuxarm@...wei.com>,
        "John Garry" <john.garry@...wei.com>,
        "xuwei (O)" <xuwei5@...wei.com>,
        "kevin.tian@...el.com" <kevin.tian@...el.com>
Subject: RE: [PATCH v7 2/6] vfio/type1: Check reserve region conflict and
 update iova list



> -----Original Message-----
> From: Shameerali Kolothum Thodi
> Sent: 04 July 2019 13:51
> To: 'Alex Williamson' <alex.williamson@...hat.com>
> Cc: eric.auger@...hat.com; kvm@...r.kernel.org;
> linux-kernel@...r.kernel.org; iommu@...ts.linux-foundation.org; Linuxarm
> <linuxarm@...wei.com>; John Garry <john.garry@...wei.com>; xuwei (O)
> <xuwei5@...wei.com>; kevin.tian@...el.com
> Subject: RE: [PATCH v7 2/6] vfio/type1: Check reserve region conflict and
> update iova list
> 
> 
> 
> > -----Original Message-----
> > From: kvm-owner@...r.kernel.org [mailto:kvm-owner@...r.kernel.org] On
> > Behalf Of Alex Williamson
> > Sent: 03 July 2019 21:34
> > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
> > Cc: eric.auger@...hat.com; pmorel@...ux.vnet.ibm.com;
> > kvm@...r.kernel.org; linux-kernel@...r.kernel.org;
> > iommu@...ts.linux-foundation.org; Linuxarm <linuxarm@...wei.com>; John
> > Garry <john.garry@...wei.com>; xuwei (O) <xuwei5@...wei.com>;
> > kevin.tian@...el.com
> > Subject: Re: [PATCH v7 2/6] vfio/type1: Check reserve region conflict and
> > update iova list
> >
> > On Wed, 26 Jun 2019 16:12:44 +0100
> > Shameer Kolothum <shameerali.kolothum.thodi@...wei.com> wrote:
> >
> > > This retrieves the reserved regions associated with dev group and
> > > checks for conflicts with any existing dma mappings. Also update
> > > the iova list excluding the reserved regions.
> > >
> > > Reserved regions with type IOMMU_RESV_DIRECT_RELAXABLE are
> > > excluded from above checks as they are considered as directly
> > > mapped regions which are known to be relaxable.
> > >
> > > Signed-off-by: Shameer Kolothum
> <shameerali.kolothum.thodi@...wei.com>
> > > ---
> > >  drivers/vfio/vfio_iommu_type1.c | 96
> > +++++++++++++++++++++++++++++++++
> > >  1 file changed, 96 insertions(+)
> > >
> > > diff --git a/drivers/vfio/vfio_iommu_type1.c
> > b/drivers/vfio/vfio_iommu_type1.c
> > > index 970d1ec06aed..b6bfdfa16c33 100644
> > > --- a/drivers/vfio/vfio_iommu_type1.c
> > > +++ b/drivers/vfio/vfio_iommu_type1.c
> > > @@ -1559,6 +1641,7 @@ static int vfio_iommu_type1_attach_group(void
> > *iommu_data,
> > >  	phys_addr_t resv_msi_base;
> > >  	struct iommu_domain_geometry geo;
> > >  	LIST_HEAD(iova_copy);
> > > +	LIST_HEAD(group_resv_regions);
> > >
> > >  	mutex_lock(&iommu->lock);
> > >
> > > @@ -1644,6 +1727,13 @@ static int vfio_iommu_type1_attach_group(void
> > *iommu_data,
> > >  		goto out_detach;
> > >  	}
> > >
> > > +	iommu_get_group_resv_regions(iommu_group,
> &group_resv_regions);
> >
> > This can fail and should have an error case.  I assume we'd fail the
> > group attach on failure.  Thanks,
> 
> Right. I will add the check. Do you think we should do the same in
> vfio_iommu_has_sw_msi()
> as well? (In fact, it looks like iommu_get_group_resv_regions() ret is not
> checked anywhere in
> kernel).

Ah..forgot the fact that patch 6/6 should take care of vfio_iommu_has_sw_msi() 
case as we are removing the duplicate iommu_get_group_resv_regions() there. 

Thanks,
Shameer