From patchwork Mon Mar 1 17:17:26 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 46574 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id B5104B7D01 for ; Tue, 2 Mar 2010 04:41:54 +1100 (EST) Received: from localhost ([127.0.0.1]:39177 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Nm9W4-0008Re-7N for incoming@patchwork.ozlabs.org; Mon, 01 Mar 2010 12:34:48 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Nm9Fj-0000DD-Or for qemu-devel@nongnu.org; Mon, 01 Mar 2010 12:17:55 -0500 Received: from [199.232.76.173] (port=41208 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Nm9Fi-0000CE-6Q for qemu-devel@nongnu.org; Mon, 01 Mar 2010 12:17:54 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1Nm9FT-0004K6-8z for qemu-devel@nongnu.org; Mon, 01 Mar 2010 12:17:53 -0500 Received: from goliath.siemens.de ([192.35.17.28]:19270) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1Nm9FP-0004J7-Tg for qemu-devel@nongnu.org; Mon, 01 Mar 2010 12:17:36 -0500 Received: from mail2.siemens.de (localhost [127.0.0.1]) by goliath.siemens.de (8.12.11.20060308/8.12.11) with ESMTP id o21HHUYK014420; Mon, 1 Mar 2010 18:17:30 +0100 Received: from localhost.localdomain (mchn012c.mchp.siemens.de [139.25.109.167] (may be forged)) by mail2.siemens.de (8.12.11.20060308/8.12.11) with ESMTP id o21HHUx6000935; Mon, 1 Mar 2010 18:17:30 +0100 From: Jan Kiszka To: Avi Kivity , Marcelo Tosatti Date: Mon, 1 Mar 2010 18:17:26 +0100 Message-Id: <9b7f3b2af517b2eb4bcca7d8e05ab5646231e868.1267463833.git.jan.kiszka@siemens.com> X-Mailer: git-send-email 1.6.0.2 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.4-2.6 Cc: Gleb Natapov , qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: [Qemu-devel] [PATCH v4 07/10] qemu-kvm: Cleanup/fix TSC and PV clock writeback X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Drop kvm_load_tsc in favor of level-dependent writeback in kvm_arch_load_regs. KVM's PV clock MSRs fall in the same category and should therefore only be written back on full sync. Signed-off-by: Jan Kiszka --- qemu-kvm-x86.c | 27 +++++++++++++-------------- qemu-kvm.h | 4 ---- target-i386/machine.c | 5 ----- 3 files changed, 13 insertions(+), 23 deletions(-) diff --git a/qemu-kvm-x86.c b/qemu-kvm-x86.c index c838a8b..8d30b05 100644 --- a/qemu-kvm-x86.c +++ b/qemu-kvm-x86.c @@ -965,8 +965,19 @@ void kvm_arch_load_regs(CPUState *env, int level) set_msr_entry(&msrs[n++], MSR_LSTAR , env->lstar); } #endif - set_msr_entry(&msrs[n++], MSR_KVM_SYSTEM_TIME, env->system_time_msr); - set_msr_entry(&msrs[n++], MSR_KVM_WALL_CLOCK, env->wall_clock_msr); + if (level == KVM_PUT_FULL_STATE) { + /* + * KVM is yet unable to synchronize TSC values of multiple VCPUs on + * writeback. Until this is fixed, we only write the offset to SMP + * guests after migration, desynchronizing the VCPUs, but avoiding + * huge jump-backs that would occur without any writeback at all. + */ + if (smp_cpus == 1 || env->tsc != 0) { + set_msr_entry(&msrs[n++], MSR_IA32_TSC, env->tsc); + } + set_msr_entry(&msrs[n++], MSR_KVM_SYSTEM_TIME, env->system_time_msr); + set_msr_entry(&msrs[n++], MSR_KVM_WALL_CLOCK, env->wall_clock_msr); + } rc = kvm_set_msrs(env, msrs, n); if (rc == -1) @@ -986,18 +997,6 @@ void kvm_arch_load_regs(CPUState *env, int level) kvm_guest_debug_workarounds(env); } -void kvm_load_tsc(CPUState *env) -{ - int rc; - struct kvm_msr_entry msr; - - set_msr_entry(&msr, MSR_IA32_TSC, env->tsc); - - rc = kvm_set_msrs(env, &msr, 1); - if (rc == -1) - perror("kvm_set_tsc FAILED.\n"); -} - void kvm_arch_save_regs(CPUState *env) { struct kvm_regs regs; diff --git a/qemu-kvm.h b/qemu-kvm.h index 7ad8f42..5c0b660 100644 --- a/qemu-kvm.h +++ b/qemu-kvm.h @@ -943,7 +943,6 @@ int handle_tpr_access(void *opaque, CPUState *env, uint64_t rip, #ifdef TARGET_I386 #define qemu_kvm_has_pit_state2() kvm_has_pit_state2(kvm_context) #endif -void kvm_load_tsc(CPUState *env); #else #define kvm_nested 0 #define qemu_kvm_has_gsi_routing() (0) @@ -951,9 +950,6 @@ void kvm_load_tsc(CPUState *env); #define qemu_kvm_has_pit_state2() (0) #endif #define qemu_kvm_cpu_stop(env) do {} while(0) -static inline void kvm_load_tsc(CPUState *env) -{ -} #endif void kvm_mutex_unlock(void); diff --git a/target-i386/machine.c b/target-i386/machine.c index bcc315b..b547e2a 100644 --- a/target-i386/machine.c +++ b/target-i386/machine.c @@ -354,11 +354,6 @@ static int cpu_post_load(void *opaque, int version_id) hw_breakpoint_insert(env, i); tlb_flush(env, 1); - - if (kvm_enabled()) { - kvm_load_tsc(env); - } - return 0; }