Messages in this thread | | | Date | Thu, 11 Jun 2015 16:25:54 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH 2/4] iommu/vt-d: Don't consider copied context entries as present |
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On Thu, Jun 11, 2015 at 03:07:02PM +0100, David Woodhouse wrote: > On Thu, 2015-06-11 at 15:47 +0200, Joerg Roedel wrote: > > From: Joerg Roedel <jroedel@suse.de> > > > > Hide the copied context entries from the IOMMU driver by > > considering them as non-present. This is implemented by > > setting the first AVL bit (bit 67) in the context entry to > > one. If this bit is set, the context_present() function > > returns false. > > > > Signed-off-by: Joerg Roedel <jroedel@suse.de> > > In the extended context entry, bit 67 is the PGE bit. There are no bits > which are available to software, to my knowledge.
Okay, reading the VT-d spec again, the extended context-entry table seem to exist in parallel to the current context-entry table, right? So this patch should still work, even with extended entries present.
If that's true, then we only need to consider the kdump case while setting up the extended context table entry (which means don't trust any content that is already there).
Joerg
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