[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen staging-4.7] gnttab: set page refcount for copy-on-grant-transfer
commit eeea811e571904b82829551fab1c648ce7051d58 Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Tue Mar 5 15:51:44 2019 +0100 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Mar 5 15:51:44 2019 +0100 gnttab: set page refcount for copy-on-grant-transfer Commit 5cc77f9098 ("32-on-64: Fix domain address-size clamping, implement"), which introduced this functionality, took care of clearing the old page's PGC_allocated, but failed to set the bit (and install the associated reference) on the newly allocated one. Furthermore the "mfn" local variable was never updated, and hence the wrong MFN was passed to guest_physmap_add_page() (and back to the destination domain) in this case, leading to an IOMMU mapping into an unowned page. Ideally the code would use assign_pages(), but the call to gnttab_prepare_for_transfer() sits in the middle of the actions mirroring that function. This is XSA-284. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Acked-by: George Dunlap <george.dunlap@xxxxxxxxxx> master commit: 6d4f36c3fecc0a6a0991716199612c81d909316e master date: 2019-03-05 13:45:58 +0100 --- xen/common/grant_table.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c index 52ab6ac111..ad44b96303 100644 --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -2011,6 +2011,8 @@ gnttab_transfer( page->count_info &= ~(PGC_count_mask|PGC_allocated); free_domheap_page(page); page = new_page; + page->count_info = PGC_allocated | 1; + mfn = page_to_mfn(page); } spin_lock(&e->page_alloc_lock); -- generated by git-patchbot for /home/xen/git/xen.git#staging-4.7 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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