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

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Message-ID: <5FC3163CFD30C246ABAA99954A238FA83F2E198C@lhreml524-mbs.china.huawei.com>
Date:   Mon, 8 Jul 2019 06:59:39 +0000
From:   Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
To:     Auger Eric <eric.auger@...hat.com>,
        Alex Williamson <alex.williamson@...hat.com>
CC:     "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

Hi Eric

> -----Original Message-----
> From: Auger Eric [mailto:eric.auger@...hat.com]
> Sent: 05 July 2019 13:10
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>;
> Alex Williamson <alex.williamson@...hat.com>
> Cc: 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
> 
> Hi Shameer,
> 
> On 7/4/19 2:51 PM, Shameerali Kolothum Thodi wrote:
> >
> >
> >> -----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).
> 
> I think the can be the topic of another series. I just noticed that in
> iommu_insert_resv_region(), which is recursive in case ot merge, I
> failed to propagate returned value or recursive calls. This also needs
> to be fixed. I volunteer to work on those changes if you prefer. Just
> let me know.

Ok. Please go ahead.

Thanks,
Shameer