From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=198.137.202.136 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794521688; b=x8dt7y5EsUz7Ys+LDJlDIIAmETvYQuMz1O0fHTDf1dcq2tAGOtvdOFJhH+LWdUP7YwKx yJqYixqU4Ny/j6mM7TdPKsP+P88F5MjokjXwRH7UvjZLkA/m8L45K4SKLR+1QHviOOag6 qVa30gCVv4xDsBymmyCzVaBGl/rlGmrPUNLbqFRjuZxz3h0NVi8qnMtY/Mb0fUbaKUBzb ryKC+JmetdbPhVqAghb6Os4eld9glJCl2aR/9J9voBGi+Yy3zyvE5t98SUZ0OBjdcWhOk yasTJyU1TLynON6/w/ndSA41WsOdSMBE2Lm5Sr91d8AIEXviJJnCc0JV50jrrXcch8A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794521688; h=DMARC-Filter:Received:DKIM-Filter:DKIM-Signature:Message-ID:Date: MIME-Version:User-Agent:Subject:To:Cc:References:Content-Language: From:In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=7XTirb6Hj6QyRMPdcPAxooRkBi3VSNvpy8OjENB+njo=; b=iIjP/M8AGLrr5U8pVfV8K6xlftcjr36dcEh5JYKCQud/4VEqdbstsemZmU3+Sc4NmAy5 PKm99W4RjY8MVpjgZs3BAIzg392D8wdNJAWRJfLngTRY462y6xjknNotXWgsOtP/XHdXo 4TcZO21ckubMm89c7iOHhyEiTESbD1yE7sjz3P4mUGJxsIfdvNlq2KFouCSRZ25t+C2EK 55X2bsAFJa75f6UPMeodupZOnw+VIeIrismrYL7g9zVk6rVDLETDcgwCRI0dfrYQXGVrr gQ2aRj0gqMDpWP28TAGJzG4HYfXKTnUyAOlptVe8mzrnlclY1zsCTF/kF0tKRIh58cQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass header.d=zytor.com header.i=@zytor.com header.a=rsa-sha256 header.s=2026102901 header.b="X4HXgj/6"; arc=none smtp.remote-ip=198.137.202.136 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 BE4AB606A31C; Thu, 12 Nov 2026 22:14:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org BE4AB606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.a=rsa-sha256 header.s=2026102901 header.b=X4HXgj/6 Received: from [IPV6:2601:646:8001:6901:cb27:19ed:d7a2:a981] ([IPv6:2601:646:8001:6901:cb27:19ed:d7a2:a981]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 6ACMDaBM1210494 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Thu, 12 Nov 2026 14:13:36 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 6ACMDaBM1210494 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026102901; t=1794521617; bh=7XTirb6Hj6QyRMPdcPAxooRkBi3VSNvpy8OjENB+njo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=X4HXgj/6OSwkOxqsyWljcVkVck+r/y6L5i/11v8PZs4qnUfLXQ0B+paObySdU8q98 cOjEeFwI2fFmxmO69XAD5MOSbJ9rr4XwQ0k0DTiWOlHhwTs5g/Oq0TLm36Rf1QYa23 OlQfhFL7JzjSX4uqdCUJFz20QX+mKftVeYoQkwfarMCcQueCWFgJO+uLLMbiMSXk8k u+RJFWJbuvtfvUPRHN8xFVLZDnCyiFfGpDqV6x0y27CziMcasvzkHmiIfWpYovGmHP dchXDRPCvhzUsZlIl49fHNd+Am1y4sYJyjgxsSjqgxoF8v4OtT49bjUmeVKeagufak gKHA6YV7Xya6A== Message-ID: <9492bce8-aab7-4982-8a0c-7d736c745e12@zytor.com> Date: Thu, 12 Nov 2026 14:13:31 -0800 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 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6.18.y] x86/cpufeatures: Make X86_FEATURE leaf 17 Linux-specific To: Borislav Petkov , Breno Leitao Cc: Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, Sean Christopherson , Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, vlad.wing@gmail.com, security@kernel.org, kernel-team@meta.com References: <20261111-stabe_srso-v1-1-45512320ba5e@debian.org> <20261112045703.GAavVHH8KA2yyCU7oc@fat_crate.local> Content-Language: en-US, sv-SE From: "H. Peter Anvin" In-Reply-To: <20261112045703.GAavVHH8KA2yyCU7oc@fat_crate.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Still, I have to wonder if it really makes sense to fold these leaves like this, since they are going to be populated soon. Surely we're not that short of bits? -hpa On 2026-11-11 20:57, Borislav Petkov wrote: > On Wed, Nov 11, 2026 at 08:06:21AM -0800, Breno Leitao wrote: >> From: "Borislav Petkov (AMD)" >> >> commit ddde4abaa0ecc8395e0fcfa3e92f65d481890cc8 upstream. >> >> That cpuinfo_x86.x86_capability[] element was supposed to mirror CPUID flags >> from CPUID_0x80000007_EBX but that leaf has still to this day only three bits >> defined in it. So move those bits to scattered.c and free the capability >> element for synthetic flags. >> >> No functional changes. >> >> [ leitao: Required on 6.18.y: the 6.18.61 backport of ae1d2082d93b >> ("x86/bugs: Adapt SRSO mitigation to Zen6") put BTB_CTX_ISOLATION in >> word 17, which here still mirrors CPUID 0x80000007 EBX. The flag is >> then falsely set on Zen3-5, and Zen5 silently loses its guest->host >> SRSO mitigation. ] > > Good catch, dang. That's nasty one. > > Thanks! >