From patchwork Thu Nov 5 03:51:03 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Liang Z" X-Patchwork-Id: 540253 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id C444C1413E0 for ; Thu, 5 Nov 2015 14:58:23 +1100 (AEDT) Received: from localhost ([::1]:58403 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuBgr-0006gh-Uv for incoming@patchwork.ozlabs.org; Wed, 04 Nov 2015 22:58:21 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43812) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuBfN-0004Xv-DX for qemu-devel@nongnu.org; Wed, 04 Nov 2015 22:56:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZuBfE-0004qx-Pz for qemu-devel@nongnu.org; Wed, 04 Nov 2015 22:56:45 -0500 Received: from mga02.intel.com ([134.134.136.20]:49823) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuBfE-0004q3-FU for qemu-devel@nongnu.org; Wed, 04 Nov 2015 22:56:40 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP; 04 Nov 2015 19:56:40 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,246,1444719600"; d="scan'208";a="843489071" Received: from ll.sh.intel.com (HELO localhost) ([10.239.13.27]) by fmsmga002.fm.intel.com with ESMTP; 04 Nov 2015 19:56:34 -0800 From: Liang Li To: qemu-devel@nongnu.org Date: Thu, 5 Nov 2015 11:51:03 +0800 Message-Id: <1446695464-27116-2-git-send-email-liang.z.li@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1446695464-27116-1-git-send-email-liang.z.li@intel.com> References: <1446695464-27116-1-git-send-email-liang.z.li@intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.20 Cc: Liang Li , ehabkost@redhat.com, mst@redhat.com, mtosatti@redhat.com, quintela@redhat.com, m.gibula@beyond.pl, amit.shah@redhat.com, pbonzini@redhat.com, rth@twiddle.net Subject: [Qemu-devel] [v2 1/2] kvmclock: add a new function to update env->tsc. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The commit 317b0a6d8 fixed an issue which caused by the outdated env->tsc value, but the fix lead to 'cpu_synchronize_all_states()' called twice during live migration. The 'cpu_synchronize_all_states()' takes about 130us for a VM which has 4 vcpus, it's a bit expensive. Synchronize the whole CPU context just for updating env->tsc is too wasting, this patch use a new function to update the env->tsc. Comparing to 'cpu_synchronize_all_states()', it only takes about 20us. Signed-off-by: Liang Li --- hw/i386/kvm/clock.c | 18 ++---------------- target-i386/kvm.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ target-i386/kvm_i386.h | 1 + 3 files changed, 48 insertions(+), 16 deletions(-) diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c index efdf165..0593a3f 100644 --- a/hw/i386/kvm/clock.c +++ b/hw/i386/kvm/clock.c @@ -17,7 +17,7 @@ #include "qemu/host-utils.h" #include "sysemu/sysemu.h" #include "sysemu/kvm.h" -#include "sysemu/cpus.h" +#include "kvm_i386.h" #include "hw/sysbus.h" #include "hw/kvm/clock.h" @@ -125,21 +125,7 @@ static void kvmclock_vm_state_change(void *opaque, int running, return; } - cpu_synchronize_all_states(); - /* In theory, the cpu_synchronize_all_states() call above wouldn't - * affect the rest of the code, as the VCPU state inside CPUState - * is supposed to always match the VCPU state on the kernel side. - * - * In practice, calling cpu_synchronize_state() too soon will load the - * kernel-side APIC state into X86CPU.apic_state too early, APIC state - * won't be reloaded later because CPUState.vcpu_dirty==true, and - * outdated APIC state may be migrated to another host. - * - * The real fix would be to make sure outdated APIC state is read - * from the kernel again when necessary. While this is not fixed, we - * need the cpu_clean_all_dirty() call below. - */ - cpu_clean_all_dirty(); + kvm_synchronize_all_tsc(); ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data); if (ret < 0) { diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 64046cb..2a9953b 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -111,6 +111,51 @@ bool kvm_allows_irq0_override(void) return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing(); } +static int kvm_get_tsc(CPUState *cs) +{ + X86CPU *cpu = X86_CPU(cs); + CPUX86State *env = &cpu->env; + struct { + struct kvm_msrs info; + struct kvm_msr_entry entries[1]; + } msr_data; + int ret; + + if (env->tsc_valid) { + return 0; + } + + msr_data.info.nmsrs = 1; + msr_data.entries[0].index = MSR_IA32_TSC; + env->tsc_valid = !runstate_is_running(); + + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data); + if (ret < 0) { + return ret; + } + + env->tsc = msr_data.entries[0].data; + return 0; +} + +static inline void do_kvm_synchronize_tsc(void *arg) +{ + CPUState *cpu = arg; + + kvm_get_tsc(cpu); +} + +void kvm_synchronize_all_tsc(void) +{ + CPUState *cpu; + + if (kvm_enabled()) { + CPU_FOREACH(cpu) { + run_on_cpu(cpu, do_kvm_synchronize_tsc, cpu); + } + } +} + static struct kvm_cpuid2 *try_get_cpuid(KVMState *s, int max) { struct kvm_cpuid2 *cpuid; diff --git a/target-i386/kvm_i386.h b/target-i386/kvm_i386.h index e557e94..c1b312b 100644 --- a/target-i386/kvm_i386.h +++ b/target-i386/kvm_i386.h @@ -15,6 +15,7 @@ bool kvm_allows_irq0_override(void); bool kvm_has_smm(void); +void kvm_synchronize_all_tsc(void); void kvm_arch_reset_vcpu(X86CPU *cs); void kvm_arch_do_init_vcpu(X86CPU *cs);