Messages in this thread | | | From | "Yu, Fenghua" <> | Subject | RE: [PATCH 200/208] x86/fpu/xstate: Don't assume the first zero xfeatures zero bit means the end | Date | Tue, 5 May 2015 23:04:41 +0000 |
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> From: Ingo Molnar [mailto:mingo.kernel.org@gmail.com] On Behalf Of Ingo > Molnar > Sent: Tuesday, May 05, 2015 10:58 AM > To: linux-kernel@vger.kernel.org > Cc: Andy Lutomirski; Borislav Petkov; Dave Hansen; Yu, Fenghua; H. Peter > Anvin; Linus Torvalds; Oleg Nesterov; Thomas Gleixner > Subject: [PATCH 200/208] x86/fpu/xstate: Don't assume the first zero > xfeatures zero bit means the end > > The current xstate code in setup_xstate_features() assumes that the first > zero bit means the end of xfeatures - but that is not so, the SDM clearly > states that an arbitrary set of xfeatures might be enabled - and it is also clear > from the description of the compaction feature that holes are possible:
A previous patch in lkml has (exactly) the same fix: http://lists-archives.com/linux-kernel/28292115-x86-xsave-c-fix-xstate-offsets-and-sizes-enumeration.html
Thanks.
-Fenghua
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