From patchwork Fri Aug 20 08:07:23 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zachary Amsden X-Patchwork-Id: 120497 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.4/8.14.3) with ESMTP id o7K89iO7002787 for ; Fri, 20 Aug 2010 08:09:44 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751861Ab0HTIIZ (ORCPT ); Fri, 20 Aug 2010 04:08:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15192 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751375Ab0HTIIW (ORCPT ); Fri, 20 Aug 2010 04:08:22 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o7K88HEp017824 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 20 Aug 2010 04:08:17 -0400 Received: from mysore (vpn-9-158.rdu.redhat.com [10.11.9.158]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o7K87qf3027969; Fri, 20 Aug 2010 04:08:14 -0400 From: Zachary Amsden To: kvm@vger.kernel.org Cc: Zachary Amsden , Avi Kivity , Marcelo Tosatti , Glauber Costa , Thomas Gleixner , John Stultz , linux-kernel@vger.kernel.org Subject: [KVM timekeeping 09/35] Unify TSC logic Date: Thu, 19 Aug 2010 22:07:23 -1000 Message-Id: <1282291669-25709-10-git-send-email-zamsden@redhat.com> In-Reply-To: <1282291669-25709-1-git-send-email-zamsden@redhat.com> References: <1282291669-25709-1-git-send-email-zamsden@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Fri, 20 Aug 2010 08:09:44 +0000 (UTC) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4b42893..324e892 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -255,7 +255,6 @@ struct kvm_mmu { }; struct kvm_vcpu_arch { - u64 host_tsc; /* * rip and regs accesses must go through * kvm_{register,rip}_{read,write} functions. @@ -336,9 +335,10 @@ struct kvm_vcpu_arch { gpa_t time; struct pvclock_vcpu_time_info hv_clock; - unsigned int hv_clock_tsc_khz; + unsigned int hw_tsc_khz; unsigned int time_offset; struct page *time_page; + u64 last_host_tsc; bool nmi_pending; bool nmi_injected; @@ -520,6 +520,7 @@ struct kvm_x86_ops { u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio); int (*get_lpage_level)(void); bool (*rdtscp_supported)(void); + void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment); void (*set_supported_cpuid)(u32 func, struct kvm_cpuid_entry2 *entry); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index e8bfe8e..2be8338 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -716,6 +716,15 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) svm->vmcb->control.tsc_offset = offset + g_tsc_offset; } +static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment) +{ + struct vcpu_svm *svm = to_svm(vcpu); + + svm->vmcb->control.tsc_offset += adjustment; + if (is_nested(svm)) + svm->nested.hsave->control.tsc_offset += adjustment; +} + static void init_vmcb(struct vcpu_svm *svm) { struct vmcb_control_area *control = &svm->vmcb->control; @@ -962,20 +971,6 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) int i; if (unlikely(cpu != vcpu->cpu)) { - u64 delta; - - if (check_tsc_unstable()) { - /* - * Make sure that the guest sees a monotonically - * increasing TSC. - */ - delta = vcpu->arch.host_tsc - native_read_tsc(); - svm->vmcb->control.tsc_offset += delta; - if (is_nested(svm)) - svm->nested.hsave->control.tsc_offset += delta; - } - vcpu->cpu = cpu; - kvm_migrate_timers(vcpu); svm->asid_generation = 0; } @@ -991,8 +986,6 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu) ++vcpu->stat.host_state_reload; for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); - - vcpu->arch.host_tsc = native_read_tsc(); } static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu) @@ -3549,6 +3542,7 @@ static struct kvm_x86_ops svm_x86_ops = { .has_wbinvd_exit = svm_has_wbinvd_exit, .write_tsc_offset = svm_write_tsc_offset, + .adjust_tsc_offset = svm_adjust_tsc_offset, }; static int __init svm_init(void) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index e3e056f..f8b70ac 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -505,7 +505,6 @@ static void __vcpu_clear(void *arg) vmcs_clear(vmx->vmcs); if (per_cpu(current_vmcs, cpu) == vmx->vmcs) per_cpu(current_vmcs, cpu) = NULL; - rdtscll(vmx->vcpu.arch.host_tsc); list_del(&vmx->local_vcpus_link); vmx->vcpu.cpu = -1; vmx->launched = 0; @@ -887,7 +886,6 @@ static void vmx_load_host_state(struct vcpu_vmx *vmx) static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - u64 tsc_this, delta, new_offset; u64 phys_addr = __pa(per_cpu(vmxarea, cpu)); if (!vmm_exclusive) @@ -904,14 +902,12 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) struct desc_ptr *gdt = &__get_cpu_var(host_gdt); unsigned long sysenter_esp; - kvm_migrate_timers(vcpu); kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); local_irq_disable(); list_add(&vmx->local_vcpus_link, &per_cpu(vcpus_on_cpu, cpu)); local_irq_enable(); - vcpu->cpu = cpu; /* * Linux uses per-cpu TSS and GDT, so set these when switching * processors. @@ -921,16 +917,6 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp); vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */ - - /* - * Make sure the time stamp counter is monotonous. - */ - rdtscll(tsc_this); - if (tsc_this < vcpu->arch.host_tsc) { - delta = vcpu->arch.host_tsc - tsc_this; - new_offset = vmcs_read64(TSC_OFFSET) + delta; - vmcs_write64(TSC_OFFSET, new_offset); - } } } @@ -1159,6 +1145,12 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) vmcs_write64(TSC_OFFSET, offset); } +static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment) +{ + u64 offset = vmcs_read64(TSC_OFFSET); + vmcs_write64(TSC_OFFSET, offset + adjustment); +} + /* * Reads an msr value (of 'msr_index') into 'pdata'. * Returns 0 on success, non-0 otherwise. @@ -4114,6 +4106,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) cpu = get_cpu(); vmx_vcpu_load(&vmx->vcpu, cpu); + vmx->vcpu.cpu = cpu; err = vmx_vcpu_setup(vmx); vmx_vcpu_put(&vmx->vcpu); put_cpu(); @@ -4353,6 +4346,7 @@ static struct kvm_x86_ops vmx_x86_ops = { .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit, .write_tsc_offset = vmx_write_tsc_offset, + .adjust_tsc_offset = vmx_adjust_tsc_offset, }; static int __init vmx_init(void) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5e3b10e..7fc4a55 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -973,9 +973,9 @@ static int kvm_write_guest_time(struct kvm_vcpu *v) return 1; } - if (unlikely(vcpu->hv_clock_tsc_khz != this_tsc_khz)) { + if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) { kvm_set_time_scale(this_tsc_khz, &vcpu->hv_clock); - vcpu->hv_clock_tsc_khz = this_tsc_khz; + vcpu->hw_tsc_khz = this_tsc_khz; } /* With all the info we got, fill in the values */ @@ -1866,13 +1866,24 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) } kvm_x86_ops->vcpu_load(vcpu, cpu); - kvm_request_guest_time_update(vcpu); + if (unlikely(vcpu->cpu != cpu)) { + /* Make sure TSC doesn't go backwards */ + s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 : + native_read_tsc() - vcpu->arch.last_host_tsc; + if (tsc_delta < 0) + mark_tsc_unstable("KVM discovered backwards TSC"); + if (check_tsc_unstable()) + kvm_x86_ops->adjust_tsc_offset(vcpu, -tsc_delta); + kvm_migrate_timers(vcpu); + vcpu->cpu = cpu; + } } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { kvm_x86_ops->vcpu_put(vcpu); kvm_put_guest_fpu(vcpu); + vcpu->arch.last_host_tsc = native_read_tsc(); } static int is_efer_nx(void)