lkml.org 
[lkml]   [2017]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] iommu/vt-d: Don't free parent pagetable of the PTE we're adding
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.

\
 
 \ /
  Last update: 2017-07-26 11:14    [W:0.056 / U:51.380 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site