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Wed, 2 Sep 2026 21:15:57 +0000 Message-ID: <36269f7b-a76f-47ee-93da-2f6bdc3d111f@intel.com> Date: Wed, 2 Sep 2026 14:15:55 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 7/8] x86/fpu: Pre-fault only required size of xstate buffer To: Andrei Vagin , Thomas Gleixner , "Ingo Molnar" , Borislav Petkov CC: , , Dave Hansen , , Alexander Mikhalitsyn , "H. Peter Anvin" References: <20260817042048.1579415-1-avagin@google.com> <20260817042048.1579415-8-avagin@google.com> Content-Language: en-US From: "Chang S. 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This can lead to attempting to fault in memory past the end of > the actual frame if the frame was smaller than the default size. > > Introduce consistency checks to calculate the actual required size for > the features enabled in the xfeatures mask, ensure that the provided > xstate_size is sufficient, and shrink it to the actual required size. > Use this validated size to fault in the user buffer. > > Keep the strict check that the provided xstate_size does not exceed the > default user_size for now. I think this consistency check should have been there already. Thanks! Reviewed-by: Chang S. Bae Thanks, Chang