path: root/virt/kvm/async_pf.c
diff options
authorDave Hansen <>2016-02-12 13:01:54 -0800
committerIngo Molnar <>2016-02-16 10:04:09 +0100
commit1e9877902dc7e11d2be038371c6fbf2dfcd469d7 (patch)
tree715a45eca4c79168f0351421a7584c95212331f8 /virt/kvm/async_pf.c
parent1fe3f29e4a908461be16a9388e73837157cc7942 (diff)
mm/gup: Introduce get_user_pages_remote()
For protection keys, we need to understand whether protections should be enforced in software or not. In general, we enforce protections when working on our own task, but not when on others. We call these "current" and "remote" operations. This patch introduces a new get_user_pages() variant: get_user_pages_remote() Which is a replacement for when get_user_pages() is called on non-current tsk/mm. We also introduce a new gup flag: FOLL_REMOTE which can be used for the "__" gup variants to get this new behavior. The uprobes is_trap_at_addr() location holds mmap_sem and calls get_user_pages(current->mm) on an instruction address. This makes it a pretty unique gup caller. Being an instruction access and also really originating from the kernel (vs. the app), I opted to consider this a 'remote' access where protection keys will not be enforced. Without protection keys, this patch should not change any behavior. Signed-off-by: Dave Hansen <> Reviewed-by: Thomas Gleixner <> Cc: Andrea Arcangeli <> Cc: Andrew Morton <> Cc: Andy Lutomirski <> Cc: Borislav Petkov <> Cc: Brian Gerst <> Cc: Dave Hansen <> Cc: Denys Vlasenko <> Cc: H. Peter Anvin <> Cc: Kirill A. Shutemov <> Cc: Linus Torvalds <> Cc: Naoya Horiguchi <> Cc: Peter Zijlstra <> Cc: Rik van Riel <> Cc: Srikar Dronamraju <> Cc: Vlastimil Babka <> Cc: Cc: Link: Signed-off-by: Ingo Molnar <>
Diffstat (limited to 'virt/kvm/async_pf.c')
1 files changed, 7 insertions, 1 deletions
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 353159922456..d604e87a510a 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -79,7 +79,13 @@ static void async_pf_execute(struct work_struct *work)
- get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL);
+ /*
+ * This work is run asynchromously to the task which owns
+ * mm and might be done in another context, so we must
+ * use FOLL_REMOTE.
+ */
+ __get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL, FOLL_REMOTE);
kvm_async_page_present_sync(vcpu, apf);