From patchwork Fri Oct 11 07:41:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Tao Xu X-Patchwork-Id: 11184943 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0244F1575 for ; Fri, 11 Oct 2019 07:41:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D599C2064A for ; Fri, 11 Oct 2019 07:41:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727632AbfJKHlI (ORCPT ); Fri, 11 Oct 2019 03:41:08 -0400 Received: from mga04.intel.com ([192.55.52.120]:5858 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727068AbfJKHlH (ORCPT ); Fri, 11 Oct 2019 03:41:07 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Oct 2019 00:41:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,283,1566889200"; d="scan'208";a="194257161" Received: from tao-optiplex-7060.sh.intel.com ([10.239.159.36]) by fmsmga007.fm.intel.com with ESMTP; 11 Oct 2019 00:41:06 -0700 From: Tao Xu To: pbonzini@redhat.com, rth@twiddle.net, ehabkost@redhat.com, mtosatti@redhat.com Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, tao3.xu@intel.com, jingqi.liu@intel.com Subject: [PATCH RESEND v6 0/2] x86: Enable user wait instructions Date: Fri, 11 Oct 2019 15:41:01 +0800 Message-Id: <20191011074103.30393-1-tao3.xu@intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions. UMONITOR arms address monitoring hardware using an address. A store to an address within the specified address range triggers the monitoring hardware to wake up the processor waiting in umwait. UMWAIT instructs the processor to enter an implementation-dependent optimized state while monitoring a range of addresses. The optimized state may be either a light-weight power/performance optimized state (c0.1 state) or an improved power/performance optimized state (c0.2 state). TPAUSE instructs the processor to enter an implementation-dependent optimized state c0.1 or c0.2 state and wake up when time-stamp counter reaches specified timeout. Availability of the user wait instructions is indicated by the presence of the CPUID feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. The patches enable the umonitor, umwait and tpause features in KVM. Because umwait and tpause can put a (psysical) CPU into a power saving state, by default we dont't expose it in kvm and provide a capability to enable it. Use kvm capability to enable UMONITOR, UMWAIT and TPAUSE when QEMU use "-overcommit cpu-pm=on, a VM can use UMONITOR, UMWAIT and TPAUSE instructions. If the instruction causes a delay, the amount of time delayed is called here the physical delay. The physical delay is first computed by determining the virtual delay (the time to delay relative to the VM’s timestamp counter). Otherwise, UMONITOR, UMWAIT and TPAUSE cause an invalid-opcode exception(#UD). The release document ref below link: https://software.intel.com/sites/default/files/\ managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf Changelog: v6: Remove CPUID_7_0_ECX_WAITPKG if enable_cpu_pm is not set. (Paolo) Tao Xu (2): x86/cpu: Add support for UMONITOR/UMWAIT/TPAUSE target/i386: Add support for save/load IA32_UMWAIT_CONTROL MSR target/i386/cpu.c | 2 +- target/i386/cpu.h | 3 +++ target/i386/kvm.c | 19 +++++++++++++++++++ target/i386/machine.c | 20 ++++++++++++++++++++ 4 files changed, 43 insertions(+), 1 deletion(-)