[PATCH v3 Bugfix 6/6] x86/xsave.c: Introduce a new check that allows correct xstates copy from kernel to user directly

From: Fenghua Yu There are two formats of XSAVE buffers: compact and standard. We avoid copying the compact format out to userspace since it might break existing userspace which is not aware of the new compacted format. This means that save_xstate_sig() can not simply copy_to_user() the kernel

[PATCH v3 Bugfix 6/6] x86/xsave.c: Introduce a new check that allows correct xstates copy from kernel to user directly

From: Fenghua Yu fenghua...@intel.com There are two formats of XSAVE buffers: compact and standard. We avoid copying the compact format out to userspace since it might break existing userspace which is not aware of the new compacted format. This means that save_xstate_sig() can not simply