Re: [Qemu-devel] [PATCH RFC v4 18/20] intel_iommu: enable vfio devices

[Peter Xu <peterx@redhat.com>]

On Mon, Jan 23, 2017 at 10:01:11AM +0800, Jason Wang wrote:
> 
> 
> On 2017年01月20日 21:08, Peter Xu wrote:
> >This patch is based on Aviv Ben-David (<bd.aviv@gmail.com>)'s patch
> >upstream:
> >
> >   "IOMMU: enable intel_iommu map and unmap notifiers"
> >   https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg01453.html
> >
> >However I removed/fixed some content, and added my own codes.
> >
> >Instead of translate() every page for iotlb invalidations (which is
> >slower), we walk the pages when needed and notify in a hook function.
> >
> >This patch enables vfio devices for VT-d emulation.
> >
> >Signed-off-by: Peter Xu<peterx@redhat.com>
> >---
> >  hw/i386/intel_iommu.c         | 66 +++++++++++++++++++++++++++++++++++++------
> >  include/hw/i386/intel_iommu.h |  8 ++++++
> >  2 files changed, 65 insertions(+), 9 deletions(-)
> 
> A good side effect of this patch is that it makes vhost device IOTLB works
> without ATS (though may be slow). We probably need a better title :)

How about I mention it in the commit message at the end? Like:

"And, since we already have vhost DMAR support via device-iotlb, a
 natural benefit that this patch brings is that vt-d enabled vhost can
 live even without ATS capability now. Though more tests are needed."

> 
> And I think we should block notifiers during PSI/DSI/GLOBAL for device with
> ATS enabled.

Again, would that be okay I note this in my todo list? :)

Thanks,

-- peterx