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Linus Torvalds
05fb07c40e
When vdpa_sim runs with use_va (the default), its rings live in user memory, and vringh reads the ring's flags and event index with __get_user() through the user address. The net and block simulators call vringh_need_notify_iotlb() with bottom halves disabled, so those reads happen in atomic context. That only works today because __get_user() has no might_fault() check: a fault is not handled in atomic context and simply comes back as -EFAULT. Make that explicit with pagefault_disable() around the call, so vringh can use the normal user accessors without complaint. Only the notification check needs this: the rest of the ring processing runs in the same kthread without bottom halves disabled, and can fault normally. Tested-and-acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>