From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-80009.amazon.com (smtp-fw-80009.amazon.com [99.78.197.220]) (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 EF4B84A07 for ; Tue, 1 Oct 2024 00:50:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727743816; cv=none; b=TcmYP1QaoZVdr9dQOBTRW4WQIt0efX3d90rPAuaWg5PcRpeW62oFBss0i3c7GMN64ECj9mnWXk0CgzP7+e7yw/RO2F0C/1ak6joKREqYcja+B4J4ccgp5C2pAFEtuz8aenQE4J6yLHJBC05rM9V9sVlEaLHewZWmS/BpIhd/StM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727743816; c=relaxed/simple; bh=nUsnwNZT6KTTkNS2id5ETl35QdiaRUy81YzL2of80Do=; h=Message-ID:Date:MIME-Version:To:CC:References:Subject:From: In-Reply-To:Content-Type; b=dbI3SqQZcF9rZ+I1j64NXSeQN+KIVRysPzfVTXjMe781VyM2hhF9QevLExYlPNjjT5d2B8vmUQwebDyDXmLZbNGhMi6YwZEpyGldBamTRe/885sOrMr366guHShKlRlkQM4GOLBHesanof2rUBAmftL4aj5eIOn8Q4RvFwJaQHc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=nQMkCisv; arc=none smtp.client-ip=99.78.197.220 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="nQMkCisv" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1727743814; x=1759279814; h=message-id:date:mime-version:to:cc:references:subject: from:in-reply-to:content-transfer-encoding; bh=nUsnwNZT6KTTkNS2id5ETl35QdiaRUy81YzL2of80Do=; b=nQMkCisvY8ZBBucqmphNiE5B0xZPjPpJhgWJZx9Sk/6AOYTdTyGL87rd VGNcMe8qI02xOmOCVC9xWz92jRFapmXecfIFs/yIJzZdJtOWqS3ubS1DA 0fxBUft6XtqvRGyO6F2tL+CnhiANC/31pOXLQRBTaDrQatkJ7xXlItIxk Y=; X-IronPort-AV: E=Sophos;i="6.11,166,1725321600"; d="scan'208";a="132718745" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-80009.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2024 00:50:14 +0000 Received: from EX19MTAUWB001.ant.amazon.com [10.0.21.151:65129] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.41.198:2525] with esmtp (Farcaster) id 0666dd8e-fe00-4345-b966-ed7de26f925d; Tue, 1 Oct 2024 00:50:14 +0000 (UTC) X-Farcaster-Flow-ID: 0666dd8e-fe00-4345-b966-ed7de26f925d Received: from EX19D003UWC002.ant.amazon.com (10.13.138.169) by EX19MTAUWB001.ant.amazon.com (10.250.64.248) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Tue, 1 Oct 2024 00:50:14 +0000 Received: from [192.168.21.242] (10.187.170.9) by EX19D003UWC002.ant.amazon.com (10.13.138.169) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.35; Tue, 1 Oct 2024 00:50:13 +0000 Message-ID: <2957b59e-25f4-4510-9053-8ad5067a60e5@amazon.com> Date: Mon, 30 Sep 2024 17:50:12 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: CC: , , , , , , , , , References: <20240912190857.235849-22-david.kaplan@amd.com> Subject: Re: [RFC PATCH 21/34] x86/bugs: Add attack vector controls for mds Content-Language: en-US From: "Manwaring, Derek" In-Reply-To: <20240912190857.235849-22-david.kaplan@amd.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: EX19D040UWA002.ant.amazon.com (10.13.139.113) To EX19D003UWC002.ant.amazon.com (10.13.138.169) On 2024-09-12 14:08-0500 David Kaplan wrote: > @@ -446,7 +450,8 @@ static void __init mds_apply_mitigation(void) >      if (mds_mitigation == MDS_MITIGATION_FULL) { >          setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF); >          if (!boot_cpu_has(X86_BUG_MSBDS_ONLY) && > -            (mds_nosmt || cpu_mitigations_auto_nosmt())) > +            (mds_nosmt || cpu_mitigations_auto_nosmt() || > +             cpu_mitigate_attack_vector(CPU_MITIGATE_CROSS_THREAD))) >              cpu_smt_disable(false); >      } >  } Maybe I'm missing something here - if you care about user/user, why would you not care about cross-thread? It seems to me SMT should be turned off for all of the vectors. Derek