On Tue, 2011-05-17 at 13:41 -0600, Alex Williamson wrote:
> On Mon, 2011-05-16 at 09:13 -0600, Alex Williamson wrote:
> > On Mon, 2011-05-09 at 15:48 +0100, David Woodhouse wrote:
> > > On Thu, 2011-05-05 at 18:13 -0700, Yinghai Lu wrote:
> > > > @@ -3252,6 +3252,9 @@ static int device_notifier(struct notifi
> > > > return 0;
> > > >
> > > > if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through) {
> > > > + /* before we remove dev with domain, flush IOTLB */
> > > > + flush_unmaps();
> > > > +
> > > > domain_remove_one_dev_info(domain, pdev);
> > > >
> > > > if (!(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) &&
> > >
> > > That calls flush_unmaps() without the async_umap_flush_lock held,
> > > doesn't it? A few days ago I asked someone else to test this candidate
> > > patch for a similar issue:
> > >
> > > http://david.woodhou.se/flush-unmaps-on-unbind.patch
> >
> > Copying here:
> >
> > > diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
> > > index d552d2c..7e606d6 100644
> > > --- a/drivers/pci/intel-iommu.c
> > > +++ b/drivers/pci/intel-iommu.c
> > > @@ -3256,8 +3259,10 @@ static int device_notifier(struct notifier_block *nb,
> > >
> > > if (!(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) &&
> > > !(domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) &&
> > > - list_empty(&domain->devices))
> > > + list_empty(&domain->devices)) {
> > > + flush_unmaps_timeout(0);
> > > domain_exit(domain);
> > > + }
> > > }
> > >
> > > return 0;
> > > @@ -3587,6 +3592,7 @@ static void intel_iommu_domain_destroy(struct iommu_domain *domain)
> > > struct dmar_domain *dmar_domain = domain->priv;
> > >
> > > domain->priv = NULL;
> > > + flush_unmaps_timeout(0);
> > > vm_domain_exit(dmar_domain);
> > > }
> >
> > David, would it be worthwhile to push the unmaps into the
> > {vm_}domain_exit() functions to avoid races like this in the future? I
> > can verify the above resolves a panic after unbinding a device from
> > snd_hda_intel that I hit recently. Do you plan to push this for .39?
>
> BTW, is this second chunk really needed? VM iommu mappings don't seem
> to use the lazy unmap path. Thanks,
David, what do you think of this instead? Thanks,
Alex
intel-iommu: Flush unmaps at domain_exit
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
We typically batch unmaps to be lazily flushed out at
regular intervals. When we destroy a domain, we need
to force a flush of these lazy unmaps to be sure none
reference the domain we're about to free.
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/pci/intel-iommu.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index d552d2c..b04f84e 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1416,6 +1416,10 @@ static void domain_exit(struct dmar_domain *domain)
if (!domain)
return;
+ /* Flush any lazy unmaps that may reference this domain */
+ if (!intel_iommu_strict)
+ flush_unmaps_timeout(0);
+
domain_remove_dev_info(domain);
/* destroy iovas */
put_iova_domain(&domain->iovad);
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
