From patchwork Thu Oct 10 05:16:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Tao Xu X-Patchwork-Id: 11182597 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 0572313BD for ; Thu, 10 Oct 2019 05:17:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4884218DE for ; Thu, 10 Oct 2019 05:17:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729045AbfJJFRD (ORCPT ); Thu, 10 Oct 2019 01:17:03 -0400 Received: from mga07.intel.com ([134.134.136.100]:13392 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726065AbfJJFRC (ORCPT ); Thu, 10 Oct 2019 01:17:02 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Oct 2019 22:17:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,279,1566889200"; d="scan'208";a="193089179" Received: from tao-optiplex-7060.sh.intel.com ([10.239.159.36]) by fmsmga008.fm.intel.com with ESMTP; 09 Oct 2019 22:17:00 -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 v6 1/2] x86/cpu: Add support for UMONITOR/UMWAIT/TPAUSE Date: Thu, 10 Oct 2019 13:16:56 +0800 Message-Id: <20191010051657.28163-2-tao3.xu@intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191010051657.28163-1-tao3.xu@intel.com> References: <20191010051657.28163-1-tao3.xu@intel.com> 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. This patch adds support for user wait instructions in KVM. Availability of the user wait instructions is indicated by the presence of the CPUID feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. User wait instructions may be executed at any privilege level, and use IA32_UMWAIT_CONTROL MSR to set the maximum time. The patch 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 to kvm and enable it only when guest CPUID has it. And use QEMU command-line "-overcommit cpu-pm=on" (enable_cpu_pm is enabled), 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 Co-developed-by: Jingqi Liu Signed-off-by: Jingqi Liu Signed-off-by: Tao Xu --- Changes in v6: - Only remove CPUID_7_0_ECX_WAITPKG if enable_cpu_pm is not set. (Paolo) --- target/i386/cpu.c | 3 ++- target/i386/cpu.h | 1 + target/i386/kvm.c | 4 ++++ 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 44f1bbdcac..631558aa49 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1058,7 +1058,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = { .type = CPUID_FEATURE_WORD, .feat_names = { NULL, "avx512vbmi", "umip", "pku", - NULL /* ospke */, NULL, "avx512vbmi2", NULL, + NULL /* ospke */, "waitpkg", "avx512vbmi2", NULL, "gfni", "vaes", "vpclmulqdq", "avx512vnni", "avx512bitalg", NULL, "avx512-vpopcntdq", NULL, "la57", NULL, NULL, NULL, @@ -5490,6 +5490,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, &cpu->mwait.ecx, &cpu->mwait.edx); env->features[FEAT_1_ECX] |= CPUID_EXT_MONITOR; + env->features[FEAT_7_0_ECX] |= CPUID_7_0_ECX_WAITPKG; } } diff --git a/target/i386/cpu.h b/target/i386/cpu.h index eaa5395aa5..4e3206c8a2 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -701,6 +701,7 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS]; #define CPUID_7_0_ECX_UMIP (1U << 2) #define CPUID_7_0_ECX_PKU (1U << 3) #define CPUID_7_0_ECX_OSPKE (1U << 4) +#define CPUID_7_0_ECX_WAITPKG (1U << 5) /* UMONITOR/UMWAIT/TPAUSE Instructions */ #define CPUID_7_0_ECX_VBMI2 (1U << 6) /* Additional VBMI Instrs */ #define CPUID_7_0_ECX_GFNI (1U << 8) #define CPUID_7_0_ECX_VAES (1U << 9) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 11b9c854b5..d2a85b1572 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -401,6 +401,10 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, if (host_tsx_blacklisted()) { ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE); } + } else if (function == 7 && index == 0 && reg == R_ECX) { + if (!enable_cpu_pm) { + ret &= ~CPUID_7_0_ECX_WAITPKG; + } } else if (function == 7 && index == 0 && reg == R_EDX) { /* * Linux v4.17-v4.20 incorrectly return ARCH_CAPABILITIES on SVM hosts.