From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:44654) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIimn-00058J-35 for qemu-devel@nongnu.org; Mon, 22 Apr 2019 19:55:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIif4-0005hY-Q5 for qemu-devel@nongnu.org; Mon, 22 Apr 2019 19:47:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46558) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hIif4-0005gt-L2 for qemu-devel@nongnu.org; Mon, 22 Apr 2019 19:47:46 -0400 From: Eduardo Habkost Date: Mon, 22 Apr 2019 20:47:40 -0300 Message-Id: <20190422234742.15780-1-ehabkost@redhat.com> Subject: [Qemu-devel] [PATCH 0/2] i386: "unavailable-features" QOM property List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Eduardo Habkost , Jiri Denemark , Igor Mammedov , Richard Henderson Currently, libvirt uses the "filtered-features" QOM property at runtime to ensure no feature was accidentally disabled on VCPUs because it's not available on the host. However, the code for "feature-words" assumes that all missing features have a corresponding CPUID bit, which is not true for MSR-based features like the ones at FEAT_ARCH_CAPABILITIES. We could extend X86CPUFeatureWordInfo to include information about MSR features, but it's impossible to do that while keeping compatibility with clients that (reasonably) expect all elements of "filtered-features" to have the cpuid-* fields. We have a field in "query-cpu-definitions" that already describes all features that are missing on a CPU, including MSR features: CpuDefinitionInfo.unavailable-features. The existing code for building the unavailable-features array even uses X86CPU::filtered_features to build the feature list. This series adds a "unavailable-features" QOM property to X86CPU objects that have the same semantics of "unavailable-features" on query-cpu-definitions. The new property has the same goal of "filtered-features", but is generic enough to let any kind of CPU feature to be listed there without relying on low level details like CPUID leaves or MSR numbers. Eduardo Habkost (2): i386: x86_cpu_list_feature_names() function i386: "unavailable-features" QOM property target/i386/cpu.c | 55 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 42 insertions(+), 13 deletions(-) -- 2.18.0.rc1.1.g3f1ff2140 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B278C10F11 for ; Mon, 22 Apr 2019 23:58:34 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DCC5020665 for ; Mon, 22 Apr 2019 23:58:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DCC5020665 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:45767 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIipV-0007SH-7C for qemu-devel@archiver.kernel.org; Mon, 22 Apr 2019 19:58:33 -0400 Received: from eggs.gnu.org ([209.51.188.92]:44654) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIimn-00058J-35 for qemu-devel@nongnu.org; Mon, 22 Apr 2019 19:55:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIif4-0005hY-Q5 for qemu-devel@nongnu.org; Mon, 22 Apr 2019 19:47:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46558) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hIif4-0005gt-L2 for qemu-devel@nongnu.org; Mon, 22 Apr 2019 19:47:46 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CA8F33093404; Mon, 22 Apr 2019 23:47:44 +0000 (UTC) Received: from localhost (ovpn-116-9.gru2.redhat.com [10.97.116.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5452C19C77; Mon, 22 Apr 2019 23:47:44 +0000 (UTC) From: Eduardo Habkost To: qemu-devel@nongnu.org Date: Mon, 22 Apr 2019 20:47:40 -0300 Message-Id: <20190422234742.15780-1-ehabkost@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 22 Apr 2019 23:47:44 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 0/2] i386: "unavailable-features" QOM property X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Jiri Denemark , Richard Henderson , Eduardo Habkost , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="UTF-8" Message-ID: <20190422234740.BqmeoBGuwkeIJtCcgolH677onKxl5YHyRTbVYLXbLbc@z> Currently, libvirt uses the "filtered-features" QOM property at runtime to ensure no feature was accidentally disabled on VCPUs because it's not available on the host. However, the code for "feature-words" assumes that all missing features have a corresponding CPUID bit, which is not true for MSR-based features like the ones at FEAT_ARCH_CAPABILITIES. We could extend X86CPUFeatureWordInfo to include information about MSR features, but it's impossible to do that while keeping compatibility with clients that (reasonably) expect all elements of "filtered-features" to have the cpuid-* fields. We have a field in "query-cpu-definitions" that already describes all features that are missing on a CPU, including MSR features: CpuDefinitionInfo.unavailable-features. The existing code for building the unavailable-features array even uses X86CPU::filtered_features to build the feature list. This series adds a "unavailable-features" QOM property to X86CPU objects that have the same semantics of "unavailable-features" on query-cpu-definitions. The new property has the same goal of "filtered-features", but is generic enough to let any kind of CPU feature to be listed there without relying on low level details like CPUID leaves or MSR numbers. Eduardo Habkost (2): i386: x86_cpu_list_feature_names() function i386: "unavailable-features" QOM property target/i386/cpu.c | 55 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 42 insertions(+), 13 deletions(-) -- 2.18.0.rc1.1.g3f1ff2140