From nobody Mon May 6 01:18:25 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; dmarc=pass(p=none dis=none) header.from=redhat.com Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1528973330609235.08456382906752; Thu, 14 Jun 2018 03:48:50 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D4C8CC04BD3D; Thu, 14 Jun 2018 10:48:47 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 59185300192F; Thu, 14 Jun 2018 10:48:47 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id D9BAE4CA80; Thu, 14 Jun 2018 10:48:45 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id w5EAmhG2025173 for ; Thu, 14 Jun 2018 06:48:44 -0400 Received: by smtp.corp.redhat.com (Postfix) id D1C2020284DE; Thu, 14 Jun 2018 10:48:43 +0000 (UTC) Received: from t460.redhat.com (unknown [10.33.36.44]) by smtp.corp.redhat.com (Postfix) with ESMTP id 15DD620284D6; Thu, 14 Jun 2018 10:48:42 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: libvir-list@redhat.com Date: Thu, 14 Jun 2018 11:48:41 +0100 Message-Id: <20180614104841.15065-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-loop: libvir-list@redhat.com Cc: Jiri Denemark , Eduardo Habkost Subject: [libvirt] [PATCH] cpu: add 'amd-ssbd' and 'amd-no-ssb' CPU features (CVE-2018-3639) X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 14 Jun 2018 10:48:49 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 AMD x86 CPUs have two separate ways to mitigate the Speculative Store Bypass hardware flaw. In current processors only non-architectural MSRs are available, and so hypervisors must expose a virtualized MSR and CPU flag "virt-ssbd" (CPUID Function 8000_0008, EBX[25]=3D1). In future processors AMD will provide an architectural MSR, indicated by existance of the CPUID Function 8000_0008, EBX[24]=3D1, to which QEMU has given the name "amd-ssbd". The "amd-ssbd" flag should be used in preference to "virt-ssbd", if it is available, since it provides improved performance. For virtual machine configuration, both should be exposed when available, to allow for maximal guest OS compatibility as not all guests yet support both. If future processes are not vulnerable to the flaw, this will be indicated by the existance of CPUID Function 8000_0008, EBX[26]=3D1, to which QEMU has given the name "amd-no-ssb". See also 124441_AMD64_SpeculativeStoreBypassDisable_Whitepaper_final.pdf from: https://bugzilla.kernel.org/show_bug.cgi?id=3D199889 Note that neither amd-ssbd or amd-no-ssb will be reported by the kernel in /proc/cpuinfo. It knows about these CPUID bits and does the right thing, but doesn't report their existance as distinct flags in /proc/cpuinfo. Signed-off-by: Daniel P. Berrang=C3=A9 Reviewed-by: Jiri Denemark --- src/cpu/cpu_map.xml | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/cpu/cpu_map.xml b/src/cpu/cpu_map.xml index 96daa0f9af..9af190a579 100644 --- a/src/cpu/cpu_map.xml +++ b/src/cpu/cpu_map.xml @@ -433,9 +433,15 @@ + + + + + + =20 --=20 2.17.0 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list