From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84380239E8A; Mon, 23 Jun 2025 10:22:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750674139; cv=none; b=h7GjhgEas2p/Hi+U1a44coAeMcrYeZcCZieT+Zs2caEcx8q9bYO2G2oOpKeAVE/Ptsr14wgFHLi4VYjKQAPyH2ZGsD3x+Hucw61hd2HugYqJR+6PGNpIG5hZPHgOCiVOq0uKP+e669HDaWnpcctjfYQWp8DzbLdgklnUAtNy21Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750674139; c=relaxed/simple; bh=buTQECq2VCKD1ICDi23k4UJqMyJjcgNtn8vEOvOp9lc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aHkltSuOZ4uPNMOZYpeRb+TRzmY8ONmb9XF4Z+dFp7izlXx0ztNGRWOOVYPbLFAGgzmZtYykN7QYnikgXn9vsIWL8R7J/ZodD5zkrCm4uKTzfek5aiuE89z9bCSKVVEvuxYAdjNOOA1UHBo56YBNq0/cJriVLjJ6Nf22fwVMTFQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=HbQHWs/l; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="HbQHWs/l" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 6633040E019C; Mon, 23 Jun 2025 10:22:13 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id X3JkVTcSfEkT; Mon, 23 Jun 2025 10:22:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1750674123; bh=bit8kbTV4D3YTiOYptKHmiW7XfvgF+MCkFLAQajwdzk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HbQHWs/ls8gZcfaGZhZv31VGHo7gwnSdUS6tcGx5ju6fZNZNY7nrxFpxNwZjLu2Oh XS7v/Ipqm7R5Gt4bJzO3gvfy9+TK/sEn4+UhrNhM2kODyyMDVofQNtyFmoAmi4pUvu 7Bof7QehSI7Qhhp6CaQIgBS2XBwOGZTRQHy9D3jF2xfNhlFkQphtrKTYysOrLuQlcd 5DZW3HGSwtZej+UmB3Q7HkqF9IHfDm5nYLDrrCzgOrASUWqXO4WHmmFy2xLrJ3Y4LB +J9SiPoSMBzFfPPuo/wXAZzC1UYbclUgVJJV0P+iFAo0GOH9d0cw3TvPC97R/QbMe+ kfoFG7keh2xnoyupNaPcs/pZm2+ZEEFNlcrVOP07MwYrwdVqsTN++R93nArt0KvMOY ydmbpOUhFb7ypo+ObodoI3r5FfJABlmwGtjNbrPsgjLll9uf+hsXla0XB1hZesRsII 0eAaH/vcQNEBsfbaHJk/dOvuGpSfecQHK5l+IqHnYT4NReLwCFb8yC7BhdFDlja4sv s4a0Hdz4FbszW8nVDNGvy3o+s+gonkxnzBWmVYIyqizfNXpKKqigDzu+ChQ2Na2PP+ ToXCf8yvBgwWs7vd0+P4AcRe9tvgUAkqSUj/RpcQUgLU50z0XqT5EuTjBVWrshIEVU ciO9IULS86WrYB8ItxO4v1dc= Received: from zn.tnic (p57969c58.dip0.t-ipconnect.de [87.150.156.88]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id D19B440E01A0; Mon, 23 Jun 2025 10:21:10 +0000 (UTC) Date: Mon, 23 Jun 2025 12:21:05 +0200 From: Borislav Petkov To: "Kirill A. Shutemov" Cc: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , 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 , Sohil Mehta , 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, Yian Chen Subject: Re: [PATCHv6 01/16] x86/cpu: Enumerate the LASS feature bits Message-ID: <20250623102105.GCaFkqkatFSbyl1YeN@fat_crate.local> References: <20250620135325.3300848-1-kirill.shutemov@linux.intel.com> <20250620135325.3300848-2-kirill.shutemov@linux.intel.com> <20250620163504.GCaFWNuI-8QFqAM0yI@fat_crate.local> <6y2iqv6c2idn7yebaec7tyhzl5zcsrwqq4lcsokumlqeophzaf@ljnmxorblgcj> <20250620182943.GDaFWolxhwogB2tTxb@fat_crate.local> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Mon, Jun 23, 2025 at 11:17:02AM +0300, Kirill A. Shutemov wrote: > What about this: > > LASS provides protection against a class of speculative attacks, such as > SLAM[1]. Add the "lass" flag to /proc/cpuinfo to indicate that the feature > is supported by hardware and enabled by the kernel. This allows userspace > to determine if the setup is secure against such attacks. Yeah, thanks. I'm still not fully on board with userspace determining whether they're mitigated or not but that's a general problem with our mitigations. Also, I haven't looked at the patchset yet but I think it should be also adding code to bugs.c to make all those vulns which it addresses, report that they're mitigated by LASS now in grep -r . /sys/devices/system/cpu/vulnerabilities/ output. Which makes your cpuinfo flag not really needed as we already have a special method for the mitigations reporting. But ok, it has gotten kernel enablement so stating so in cpuinfo is ok. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette