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[92.21.58.28]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-454b168664bsm78214565e9.20.2025.07.06.02.22.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 06 Jul 2025 02:22:16 -0700 (PDT) Date: Sun, 6 Jul 2025 10:22:13 +0100 From: David Laight To: "H. Peter Anvin" Cc: Sohil Mehta , "Kirill A. Shutemov" , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Peter Zijlstra , Ard Biesheuvel , "Paul E. McKenney" , Josh Poimboeuf , Xiongwei Song , Xin Li , "Mike Rapoport (IBM)" , Brijesh Singh , Michael Roth , Tony Luck , Alexey Kardashevskiy , Alexander Shishkin , Jonathan Corbet , Ingo Molnar , Pawan Gupta , Daniel Sneddon , Kai Huang , Sandipan Das , Breno Leitao , Rick Edgecombe , Alexei Starovoitov , Hou Tao , Juergen Gross , Vegard Nossum , Kees Cook , Eric Biggers , Jason Gunthorpe , "Masami Hiramatsu (Google)" , Andrew Morton , Luis Chamberlain , Yuntao Wang , Rasmus Villemoes , Christophe Leroy , Tejun Heo , Changbin Du , Huang Shijie , Geert Uytterhoeven , Namhyung Kim , Arnaldo Carvalho de Melo , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv8 14/17] x86/traps: Handle LASS thrown #SS Message-ID: <20250706102213.4ab365d7@pumpkin> In-Reply-To: <4DE45AFD-C1E0-4FB8-BE01-44A72C5C6E1E@zytor.com> References: <20250701095849.2360685-1-kirill.shutemov@linux.intel.com> <20250701095849.2360685-15-kirill.shutemov@linux.intel.com> <95dc18fd-73b0-4019-92d2-c0e6aaf22c96@intel.com> <4DE45AFD-C1E0-4FB8-BE01-44A72C5C6E1E@zytor.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6C5E6120003 X-Stat-Signature: u4orstr9445iar4fh4tugoypiz8zeccc X-Rspam-User: X-HE-Tag: 1751793738-371581 X-HE-Meta: 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 QIadhuaf 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 01 Jul 2025 19:06:10 -0700 "H. Peter Anvin" wrote: ... > Note: for a FRED system, ERETU can generate #SS for a non-canonical user space > RSP even in the absence of LASS, so if that is not currently handled that is an active bug. Is that a fault in kernel space, or a fault in user space. Some of the traps for 'iret' happen after the transition to user space, so the kernel doesn't have to handle them as special cases. (I simplified (and fixed) one version of that code.) David