From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=90.155.92.199 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792618627; b=guGPe4VlQ6TSO6Y+nU2WdwGN2gbQwO09Oq3aPgiK/cLLvTBZ0FRD9Ihj/s/QL665nzuk YDg3gr6w/JGcGFK/Zbq7iUBRi4w8YXHpeJvdOMaLSPK5VO/SmqC3qBzW46ykGJElt7NC8 LBh0Fv4TAVsmCrXfihuHO8jAFCc+FQFloTskPr01XoqwEi9Sq+CyrdueX+Q/fvrm7X9Po ZZNRXW0Vj+j8qKeiAwwrnCVuzCOjz1nm5FsbV1+CqFGm1hT6KXoAUfUZISPWFfGWPQVOa RWUGPwW5UZvXI9F2cDQUeXLkTpR4JT6jEACovQDux8JfL5JrapP2ASpBHvcWVUG1xhw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792618627; h=DMARC-Filter:DKIM-Signature:Received:Received:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=sJ990sqZ4/ri6q2ejelZgxO4KylZ9CPLKUVlUc+fxbE=; b=gicVdNzm55RCjn4XKipOQXLkNfUp+P4jMrvNBRiM+oe+a6M1RnsCcQpYh62KFK1otTID iG1L97IWbsNJSbtrZJxT3T92JUXZtKt1h/ItLddM8Ga1wyI1PAZgf06fc7M5qJQtEHEVw lOhm/fp0VxxRnhZXCorTQ+yBuoQ2GXEJyOlywxcTTfMGOteMOT1HAI4to0NlgJ3uxYcfU QPJnHHBz+/aPuRbpZWYpCeKzRvtyhHa9FdCcf74O2k9hwfhSEZNzNtCeFlV68afJC8XmW COMRBqzVCvFuPy6igHgvG5gU9SuIlKCrzBZuex9wN1douzZtU+nU+9IqDFNHlalxjJA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b="izrIMM/K"; arc=none smtp.remote-ip=90.155.92.199 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1DD59606A32F for ; Wed, 21 Oct 2026 21:37:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1DD59606A32F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b=izrIMM/K DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=sJ990sqZ4/ri6q2ejelZgxO4KylZ9CPLKUVlUc+fxbE=; b=izrIMM/KmRR/slCxkIfq8rXF+u ZDvGkmYRjZa+8/Wi/yZI07DyNDvLMJdCrjPvoJp0ejIKki8yBHI11rlY+yUBTWX4uAf66aUdTyAn3 gRgCgeu8xKzfzppKyPoO0jxN2BpKEGTZhKu03RFhQeU2usMJoFYXPPMzdQ3Ak+0fes6qi/9/zPO9z zFFfdCbrtMrwb6i4edHU7NNFvjcjyooUDRvRK0PT5wKLP8uW7IRtPMx5EsUcapVzGv746ipL2GpMH RPnAj+3pNuW2u7025dgDbkLT8XkpEjUqmwKOja7hvmEIpsLvVhMk18UKTZG7uE57IpeBR3eYDF5hi PTCEH5Wg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.5 #2 (Red Hat Linux)) id 1xJdzP-00000006Ffb-2DyN; Wed, 21 Oct 2026 21:36:52 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id AF3763005AA; Wed, 21 Oct 2026 23:36:49 +0200 (CEST) Date: Wed, 21 Oct 2026 23:36:49 +0200 From: Peter Zijlstra To: Dave Hansen Cc: linux-kernel@vger.kernel.org, Andy Lutomirski , Edgecombe@programming.kicks-ass.net, Rick P , Andrew Cooper , the arch/x86 maintainers , Kees Cook , Pawan Gupta , Borislav Petkov , Thomas Gleixner Subject: Re: [RFC][PATCH 00/24] x86 Kernel Shadow Stacks Message-ID: <20261021213649.GS2823843@noisy.programming.kicks-ass.net> References: <20261021195120.E61EC737@davehans-spike.ostc.intel.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261021195120.E61EC737@davehans-spike.ostc.intel.com> On Wed, Oct 21, 2026 at 12:51:20PM -0700, Dave Hansen wrote: > * Work with IDT-based systems (without FRED) This simply cannot work -- IDT relies on that horrific NMI nesting stuff, and shadow stacks hate on that something fierce.