From nobody Thu May 2 23:49:08 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1528416449643215.9427526692075; Thu, 7 Jun 2018 17:07:29 -0700 (PDT) Received: from localhost ([::1]:60653 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fR4w4-0000xg-Ch for importer@patchew.org; Thu, 07 Jun 2018 20:07:20 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38504) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fR4v9-0000em-5H for qemu-devel@nongnu.org; Thu, 07 Jun 2018 20:06:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fR4v5-0006fk-Vj for qemu-devel@nongnu.org; Thu, 07 Jun 2018 20:06:23 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50724 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fR4v5-0006f1-PQ for qemu-devel@nongnu.org; Thu, 07 Jun 2018 20:06:19 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E1FE540BC060; Fri, 8 Jun 2018 00:06:18 +0000 (UTC) Received: from redhat.com (ovpn-120-126.rdu2.redhat.com [10.10.120.126]) by smtp.corp.redhat.com (Postfix) with SMTP id 6BF056B5BF; Fri, 8 Jun 2018 00:06:18 +0000 (UTC) Date: Fri, 8 Jun 2018 03:06:12 +0300 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <20180608000540.276617-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Fri, 08 Jun 2018 00:06:18 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Fri, 08 Jun 2018 00:06:18 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mst@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH] kvm: support -realtime cpu-pm=on|off 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 , Marcelo Tosatti , Eduardo Habkost , kvm@vger.kernel.org, Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Acked-by: Paolo Bonzini --- include/sysemu/sysemu.h | 1 + target/i386/kvm.c | 26 ++++++++++++++++++++++++++ vl.c | 6 ++++++ qemu-options.hx | 9 +++++++-- 4 files changed, 40 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..e4c3e65e00 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -1041,6 +1041,32 @@ int kvm_arch_init_vcpu(CPUState *cs) } } =20 + if (enable_cpu_pm) { + int disable_exits =3D kvm_check_extension(cs->kvm_state, KVM_CAP_X= 86_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_H= LT) +#define KVM_X86_DISABLE_EXITS_HLT KVM_X86_DISABLE_EXITS_HTL +#endif + if (disable_exits) { + disable_exits &=3D (KVM_X86_DISABLE_EXITS_MWAIT | + KVM_X86_DISABLE_EXITS_HLT | + KVM_X86_DISABLE_EXITS_PAUSE); + /* PV unhalt relies on HALT to cause an exit */ + if (env->user_features[FEAT_KVM] & (1U << KVM_FEATURE_PV_UNHAL= T)) { + disable_exits &=3D ~KVM_X86_DISABLE_EXITS_HLT; + } + } + + ret =3D kvm_vm_enable_cap(cs->kvm_state, KVM_CAP_X86_DISABLE_EXITS= , 0, + disable_exits); + if (ret < 0) { + error_report("kvm: guest stopping CPU not supported: %s", stre= rror(-ret)); + } + } + + qemu_add_vm_change_state_handler(cpu_update_state, env); =20 c =3D cpuid_find_entry(&cpuid_data.cpuid, 1, 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 =3D NULL; int mem_prealloc =3D 0; /* force preallocation of physical target memory */ bool enable_mlock =3D false; +bool enable_cpu_pm =3D false; int nb_nics; NICInfo nd_table[MAX_NICS]; int autostart; @@ -386,6 +387,10 @@ static QemuOptsList qemu_realtime_opts =3D { .name =3D "mlock", .type =3D QEMU_OPT_BOOL, }, + { + .name =3D "cpu-pm", + .type =3D QEMU_OPT_BOOL, + }, { /* end of list */ } }, }; @@ -3904,6 +3909,7 @@ int main(int argc, char **argv, char **envp) exit(1); } enable_mlock =3D qemu_opt_get_bool(opts, "mlock", true); + enable_cpu_pm =3D qemu_opt_get_bool(opts, "cpu-pm", false); break; case QEMU_OPTION_msg: opts =3D qemu_opts_parse_noisily(qemu_find_opts("msg"), op= targ, 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 t= he monitor). ETEXI =20 DEF("realtime", HAS_ARG, QEMU_OPTION_realtime, - "-realtime [mlock=3Don|off]\n" + "-realtime [mlock=3Don|off][cpu-halt=3Don|off[\n" " run qemu with realtime features\n" - " mlock=3Don|off controls mlock support (default: on)\n= ", + " mlock=3Don|off controls mlock support (default: on)\n" + " cpu-pm=3Don|off controls cpu power management (defaul= t: off)\n", QEMU_ARCH_ALL) STEXI @item -realtime mlock=3Don|off +@item -realtime cpu-pm=3Don|off @findex -realtime Run qemu with realtime features. mlocking qemu and guest memory can be enabled via @option{mlock=3Don} (enabled by default). +guest ability to manage power state of host cpus (increasing latency for o= ther +processes on the same host cpu, but decreasing latency for guest) +can be enabled via @option{cpu-pm=3Don} (disabled by default). ETEXI =20 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ --=20 MST