Messages in this thread | | | Date | Wed, 26 Jul 2017 11:13:31 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] iommu/vt-d: Don't free parent pagetable of the PTE we're adding |
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On Wed, Jun 28, 2017 at 07:42:23PM -0700, David Dillow wrote: > When adding a large scatterlist entry that covers more than the L3 > superpage size (1GB) but has an alignment such that we must use L2 > superpages (2MB) , we give dma_pte_free_level() a range that causes it > to free the L3 pagetable we're about to populate. We fix this by telling > dma_pte_free_pagetable() about the pagetable level we're about to populate > to prevent freeing it. > > For example, mapping a scatterlist with entry lengths 854MB and 1194MB > at IOVA 0xffff80000000 would, when processing the 2MB-aligned second > entry, cause pfn_to_dma_pte() to create a L3 directory to hold L2 > superpages for the mapping at IOVA 0xffffc0000000. We would previously > call dma_pte_free_pagetable(domain, 0xffffc0000, 0xfffffffff), which > would free the L3 directory pfn_to_dma_pte() just created for IO PFN > 0xffffc0000. Telling dma_pte_free_pagetable() to retain the L3 > directories while using L2 superpages avoids the erroneous free. > > Signed-off-by: David Dillow <dillow@google.com> > --- > drivers/iommu/intel-iommu.c | 38 ++++++++++++++++++++++++++------------ > 1 file changed, 26 insertions(+), 12 deletions(-)
Applied, thanks.
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