From patchwork Sun Sep 29 01:57:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Tao Xu X-Patchwork-Id: 11165597 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 E48451747 for ; Sun, 29 Sep 2019 02:02:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD1BE214D8 for ; Sun, 29 Sep 2019 02:02:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728831AbfI2B5X (ORCPT ); Sat, 28 Sep 2019 21:57:23 -0400 Received: from mga03.intel.com ([134.134.136.65]:14348 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728569AbfI2B5X (ORCPT ); Sat, 28 Sep 2019 21:57:23 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Sep 2019 18:57:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,561,1559545200"; d="scan'208";a="204501452" Received: from tao-optiplex-7060.sh.intel.com ([10.239.159.36]) by fmsmga001.fm.intel.com with ESMTP; 28 Sep 2019 18:57:21 -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 v5 1/2] x86/cpu: Add support for UMONITOR/UMWAIT/TPAUSE Date: Sun, 29 Sep 2019 09:57:17 +0800 Message-Id: <20190929015718.19562-2-tao3.xu@intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190929015718.19562-1-tao3.xu@intel.com> References: <20190929015718.19562-1-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 v5: - 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 | 6 ++++++ 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 9e0bac31e8..15f888b13f 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1062,7 +1062,7 @@ 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, @@ -5227,6 +5227,7 @@ 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 5f6e3a029a..33a0b8b365 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -673,6 +673,7 @@ typedef uint32_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 92069099ab..ea9a87bfd8 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -400,6 +400,12 @@ 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 { + 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.