From patchwork Tue Jun 12 18:47:11 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 10460887 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 887E56020F for ; Tue, 12 Jun 2018 18:47:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 76C8328A0A for ; Tue, 12 Jun 2018 18:47:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6B5A428A12; Tue, 12 Jun 2018 18:47:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EF53928A0A for ; Tue, 12 Jun 2018 18:47:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754060AbeFLSrP (ORCPT ); Tue, 12 Jun 2018 14:47:15 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45034 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752954AbeFLSrN (ORCPT ); Tue, 12 Jun 2018 14:47:13 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 00127401CE8B; Tue, 12 Jun 2018 18:47:12 +0000 (UTC) Received: from redhat.com (ovpn-121-153.rdu2.redhat.com [10.10.121.153]) by smtp.corp.redhat.com (Postfix) with SMTP id 4FC0B20283A3; Tue, 12 Jun 2018 18:47:12 +0000 (UTC) Date: Tue, 12 Jun 2018 21:47:11 +0300 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Marcelo Tosatti , Richard Henderson , Eduardo Habkost , kvm@vger.kernel.org Subject: [PATCH v2 1/2] kvm: support -realtime cpu-pm=on|off Message-ID: <20180612184616.90838-2-mst@redhat.com> References: <20180612184616.90838-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180612184616.90838-1-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Tue, 12 Jun 2018 18:47:13 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Tue, 12 Jun 2018 18:47:13 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mst@redhat.com' RCPT:'' Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP With this flag, kvm allows guest to control host CPU power state. This increases latency for other processes using same host CPU in an unpredictable way, but if decreases idle entry/exit times for the running VCPU. Follow-up patches will expose this capability to guest (using mwait leaf). Based on a patch by Wanpeng Li . Signed-off-by: Michael S. Tsirkin --- include/sysemu/sysemu.h | 1 + target/i386/kvm.c | 22 ++++++++++++++++++++++ vl.c | 6 ++++++ qemu-options.hx | 9 +++++++-- 4 files changed, 36 insertions(+), 2 deletions(-) diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index e893f72f3b..b921c6f3b7 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -128,6 +128,7 @@ extern bool boot_strict; extern uint8_t *boot_splash_filedata; extern size_t boot_splash_filedata_size; extern bool enable_mlock; +extern bool enable_cpu_pm; extern uint8_t qemu_extra_params_fw[2]; extern QEMUClockType rtc_clock; extern const char *mem_path; diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 44f70733e7..f093d55209 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -1357,6 +1357,28 @@ int kvm_arch_init(MachineState *ms, KVMState *s) smram_machine_done.notify = register_smram_listener; qemu_add_machine_init_done_notifier(&smram_machine_done); } + + if (enable_cpu_pm) { + int disable_exits = kvm_check_extension(s, KVM_CAP_X86_DISABLE_EXITS); + int ret; + +/* Work around for kernel header with a typo. TODO: fix header and drop. */ +#if defined(KVM_X86_DISABLE_EXITS_HTL) && !defined(KVM_X86_DISABLE_EXITS_HLT) +#define KVM_X86_DISABLE_EXITS_HLT KVM_X86_DISABLE_EXITS_HTL +#endif + if (disable_exits) { + disable_exits &= (KVM_X86_DISABLE_EXITS_MWAIT | + KVM_X86_DISABLE_EXITS_HLT | + KVM_X86_DISABLE_EXITS_PAUSE); + } + + ret = kvm_vm_enable_cap(s, KVM_CAP_X86_DISABLE_EXITS, 0, + disable_exits); + if (ret < 0) { + error_report("kvm: guest stopping CPU not supported: %s", strerror(-ret)); + } + } + return 0; } diff --git a/vl.c b/vl.c index 06031715ac..7bea9c2177 100644 --- a/vl.c +++ b/vl.c @@ -142,6 +142,7 @@ ram_addr_t ram_size; const char *mem_path = NULL; int mem_prealloc = 0; /* force preallocation of physical target memory */ bool enable_mlock = false; +bool enable_cpu_pm = false; int nb_nics; NICInfo nd_table[MAX_NICS]; int autostart; @@ -386,6 +387,10 @@ static QemuOptsList qemu_realtime_opts = { .name = "mlock", .type = QEMU_OPT_BOOL, }, + { + .name = "cpu-pm", + .type = QEMU_OPT_BOOL, + }, { /* end of list */ } }, }; @@ -3904,6 +3909,7 @@ int main(int argc, char **argv, char **envp) exit(1); } enable_mlock = qemu_opt_get_bool(opts, "mlock", true); + enable_cpu_pm = qemu_opt_get_bool(opts, "cpu-pm", false); break; case QEMU_OPTION_msg: opts = qemu_opts_parse_noisily(qemu_find_opts("msg"), optarg, diff --git a/qemu-options.hx b/qemu-options.hx index c0d3951e9f..e6f31071ce 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3325,16 +3325,21 @@ Do not start CPU at startup (you must type 'c' in the monitor). ETEXI DEF("realtime", HAS_ARG, QEMU_OPTION_realtime, - "-realtime [mlock=on|off]\n" + "-realtime [mlock=on|off][cpu-halt=on|off[\n" " run qemu with realtime features\n" - " mlock=on|off controls mlock support (default: on)\n", + " mlock=on|off controls mlock support (default: on)\n" + " cpu-pm=on|off controls cpu power management (default: off)\n", QEMU_ARCH_ALL) STEXI @item -realtime mlock=on|off +@item -realtime cpu-pm=on|off @findex -realtime Run qemu with realtime features. mlocking qemu and guest memory can be enabled via @option{mlock=on} (enabled by default). +guest ability to manage power state of host cpus (increasing latency for other +processes on the same host cpu, but decreasing latency for guest) +can be enabled via @option{cpu-pm=on} (disabled by default). ETEXI DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \