On Mon, Feb 22, 2021 at 01:55:23PM -0400, Jason Gunthorpe wrote:
> > +static bool strict_mmio_maps = true;
> > +module_param_named(strict_mmio_maps, strict_mmio_maps, bool, 0644);
> > +MODULE_PARM_DESC(strict_mmio_maps,
> > +"Restrict to safe DMA mappings of device memory (true).");
>
On Thu, Feb 25, 2021 at 03:17:14PM -0400, Jason Gunthorpe wrote:
> It is a use-after-free. Once the PFN is programmed into the IOMMU it
> becomes completely divorced from the VMA. Remember there is no
> pin_user_page here, so the PFN has no reference count.
>
> If the owner of the VMA decided to
On Thu, Feb 25, 2021 at 02:06:46PM -0500, Peter Xu wrote:
> Agreed. I saw discussions around on redefining the vm_pgoff namespace, I
> can't
> say I followed that closely either, but yes it definitely makes sense to
> always
> use an unified namespace. Maybe we should even comment it
On Thu, Feb 25, 2021 at 02:19:45PM -0400, Jason Gunthorpe wrote:
> On Thu, Feb 25, 2021 at 12:54:57PM -0500, Peter Xu wrote:
>
> > I can't say I fully understand the whole rational behind 5cbf3264bc71, but
> > that
> > commit still sounds reasonable to me, since I don't see why VFIO cannot do
>
On Thu, Feb 25, 2021 at 12:54:57PM -0500, Peter Xu wrote:
> I can't say I fully understand the whole rational behind 5cbf3264bc71, but
> that
> commit still sounds reasonable to me, since I don't see why VFIO cannot do
> VFIO_IOMMU_MAP_DMA upon another memory range that's neither anonymous
On Wed, Feb 24, 2021 at 08:22:16PM -0400, Jason Gunthorpe wrote:
> On Wed, Feb 24, 2021 at 02:55:08PM -0700, Alex Williamson wrote:
>
> > > > +static bool strict_mmio_maps = true;
> > > > +module_param_named(strict_mmio_maps, strict_mmio_maps, bool, 0644);
> > > >
On Wed, Feb 24, 2021 at 02:55:08PM -0700, Alex Williamson wrote:
> > > +static bool strict_mmio_maps = true;
> > > +module_param_named(strict_mmio_maps, strict_mmio_maps, bool, 0644);
> > > +MODULE_PARM_DESC(strict_mmio_maps,
> > > + "Restrict to safe DMA mappings of device memory
On Mon, 22 Feb 2021 13:55:23 -0400
Jason Gunthorpe wrote:
> On Mon, Feb 22, 2021 at 09:52:32AM -0700, Alex Williamson wrote:
> > Introduce a new default strict MMIO mapping mode where the vma for
> > a VM_PFNMAP mapping must be backed by a vfio device. This allows
> > holding a reference to the
On Mon, Feb 22, 2021 at 09:52:32AM -0700, Alex Williamson wrote:
> Introduce a new default strict MMIO mapping mode where the vma for
> a VM_PFNMAP mapping must be backed by a vfio device. This allows
> holding a reference to the device and registering a notifier for the
> device, which
Introduce a new default strict MMIO mapping mode where the vma for
a VM_PFNMAP mapping must be backed by a vfio device. This allows
holding a reference to the device and registering a notifier for the
device, which additionally keeps the device in an IOMMU context for
the extent of the DMA
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