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

[Shameerali Kolothum Thodi]

> -----Original Message-----
> From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On
> Behalf Of Alex Williamson
> Sent: 03 July 2019 21:34
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>
> Cc: eric.auger@xxxxxxxxxx; pmorel@xxxxxxxxxxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; Linuxarm <linuxarm@xxxxxxxxxx>; John
> Garry <john.garry@xxxxxxxxxx>; xuwei (O) <xuwei5@xxxxxxxxxx>;
> kevin.tian@xxxxxxxxx
> 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@xxxxxxxxxx> 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@xxxxxxxxxx>
> > ---
> >  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). 

Thanks,
Shameer