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Date: Mon, 19 Feb 2018 10:00:53 +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>,
"pmorel@...ux.vnet.ibm.com" <pmorel@...ux.vnet.ibm.com>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Linuxarm <linuxarm@...wei.com>,
John Garry <john.garry@...wei.com>,
"xuwei (O)" <xuwei5@...wei.com>
Subject: RE: [PATCH v3 2/6] vfio/type1: Check reserve region conflict and
update iova list
> -----Original Message-----
> From: Alex Williamson [mailto:alex.williamson@...hat.com]
> Sent: Friday, February 16, 2018 9:18 PM
> 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; Linuxarm
> <linuxarm@...wei.com>; John Garry <john.garry@...wei.com>; xuwei (O)
> <xuwei5@...wei.com>
> Subject: Re: [PATCH v3 2/6] vfio/type1: Check reserve region conflict and
> update iova list
>
> On Thu, 15 Feb 2018 09:45:00 +0000
> 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.
> >
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
> > ---
> > drivers/vfio/vfio_iommu_type1.c | 86
> ++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 85 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vfio/vfio_iommu_type1.c
> b/drivers/vfio/vfio_iommu_type1.c
> > index 4726f55..4db87a9 100644
> > --- a/drivers/vfio/vfio_iommu_type1.c
> > +++ b/drivers/vfio/vfio_iommu_type1.c
> > @@ -1303,6 +1303,72 @@ static int vfio_iommu_aper_resize(struct
> list_head *iova,
> > return 0;
> > }
> >
> > +/*
> > + * Check reserved region conflicts with existing dma mappings
> > + */
> > +static bool vfio_iommu_resv_conflict(struct vfio_iommu *iommu,
> > + struct list_head *resv_regions)
> > +{
> > + struct iommu_resv_region *region;
> > +
> > + /* Check for conflict with existing dma mappings */
> > + list_for_each_entry(region, resv_regions, list) {
> > + if (vfio_find_dma(iommu, region->start, region->length))
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > +/*
> > + * Check iova region overlap with reserved regions and
> > + * exclude them from the iommu iova range
> > + */
> > +static int vfio_iommu_resv_exclude(struct list_head *iova,
> > + struct list_head *resv_regions)
> > +{
> > + struct iommu_resv_region *resv;
> > + struct vfio_iova *n, *next;
> > +
> > + list_for_each_entry(resv, resv_regions, list) {
> > + phys_addr_t start, end;
> > +
> > + start = resv->start;
> > + end = resv->start + resv->length - 1;
> > +
> > + list_for_each_entry_safe(n, next, iova, list) {
> > + int ret = 0;
> > +
> > + /* No overlap */
> > + if ((start > n->end) || (end < n->start))
> > + continue;
> > + /*
> > + * Insert a new node if current node overlaps with the
> > + * reserve region to exlude that from valid iova range.
> > + * Note that, new node is inserted before the current
> > + * node and finally the current node is deleted keeping
> > + * the list updated and sorted.
> > + */
> > + if (start > n->start)
> > + ret = vfio_insert_iova(n->start, start - 1,
> > + &n->list);
> > + if (!ret && end < n->end)
> > + ret = vfio_insert_iova(end + 1, n->end,
> > + &n->list);
> > + if (ret)
> > + return ret;
> > +
> > + list_del(&n->list);
> > + kfree(n);
> > + }
> > + }
> > +
> > + if (list_empty(iova))
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > static int vfio_iommu_get_iova_copy(struct vfio_iommu *iommu,
> > struct list_head *iova_copy)
> > {
> > @@ -1346,7 +1412,8 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> > bool resv_msi, msi_remap;
> > phys_addr_t resv_msi_base;
> > struct iommu_domain_geometry geo;
> > - struct list_head iova_copy;
> > + struct list_head iova_copy, group_resv_regions;
> > + struct iommu_resv_region *resv, *resv_next;
> > struct vfio_iova *iova, *iova_next;
> >
> > mutex_lock(&iommu->lock);
> > @@ -1426,6 +1493,14 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> > goto out_detach;
> > }
> >
> > + INIT_LIST_HEAD(&group_resv_regions);
>
> LIST_HEAD()
Ok.
> > + iommu_get_group_resv_regions(iommu_group, &group_resv_regions);
> > +
> > + if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) {
> > + ret = -EINVAL;
> > + goto out_detach;
> > + }
> > +
> > /* Get a copy of the current iova list and work on it */
> > INIT_LIST_HEAD(&iova_copy);
> > ret = vfio_iommu_get_iova_copy(iommu, &iova_copy);
> > @@ -1437,6 +1512,10 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> > if (ret)
> > goto out_detach;
> >
> > + ret = vfio_iommu_resv_exclude(&iova_copy, &group_resv_regions);
> > + if (ret)
> > + goto out_detach;
> > +
> > resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base);
> >
> > INIT_LIST_HEAD(&domain->group_list);
> > @@ -1497,6 +1576,9 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> > /* Delete the old one and insert new iova list */
> > vfio_iommu_insert_iova_copy(iommu, &iova_copy);
> >
> > + list_for_each_entry_safe(resv, resv_next, &group_resv_regions, list)
> > + kfree(resv);
>
> list_del() here and below, also this can be done after the mutex unlock.
Ok. I thought that as the reserved regions are local to this function, list_del() is
not required. Same for the iova_copy in the first patch as well(which I missed to
comment there).
Thanks,
Shameer
> > +
> > mutex_unlock(&iommu->lock);
> >
> > return 0;
> > @@ -1507,6 +1589,8 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> > iommu_domain_free(domain->domain);
> > list_for_each_entry_safe(iova, iova_next, &iova_copy, list)
> > kfree(iova);
> > + list_for_each_entry_safe(resv, resv_next, &group_resv_regions, list)
> > + kfree(resv);
> > out_free:
> > kfree(domain);
> > kfree(group);
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