Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752758Ab0HTIQa (ORCPT ); Fri, 20 Aug 2010 04:16:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38585 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751639Ab0HTIIK (ORCPT ); Fri, 20 Aug 2010 04:08:10 -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 03/35] Move TSC offset writes to common code Date: Thu, 19 Aug 2010 22:07:17 -1000 Message-Id: <1282291669-25709-4-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> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5244 Lines: 166 Also, ensure that the storing of the offset and the reading of the TSC are never preempted by taking a spinlock. While the lock is overkill now, it is useful later in this patch series. Signed-off-by: Zachary Amsden --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/svm.c | 6 ++++-- arch/x86/kvm/vmx.c | 13 ++++++------- arch/x86/kvm/x86.c | 18 ++++++++++++++++++ arch/x86/kvm/x86.h | 2 ++ 5 files changed, 33 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 960f9c9..3b4efe2 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -395,6 +395,7 @@ struct kvm_arch { unsigned long irq_sources_bitmap; s64 kvmclock_offset; + spinlock_t tsc_write_lock; struct kvm_xen_hvm_config xen_hvm_config; @@ -521,6 +522,8 @@ struct kvm_x86_ops { bool (*has_wbinvd_exit)(void); + void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset); + const struct trace_print_flags *exit_reasons_str; }; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 4cb8822..8d7ae20 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2581,8 +2581,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data) struct vcpu_svm *svm = to_svm(vcpu); switch (ecx) { - case MSR_IA32_TSC: - svm_write_tsc_offset(vcpu, data - native_read_tsc()); + case MSR_IA32_TSC: + kvm_write_tsc(vcpu, data); break; case MSR_K6_STAR: svm->vmcb->save.star = data; @@ -3547,6 +3547,8 @@ static struct kvm_x86_ops svm_x86_ops = { .set_supported_cpuid = svm_set_supported_cpuid, .has_wbinvd_exit = svm_has_wbinvd_exit, + + .write_tsc_offset = svm_write_tsc_offset, }; static int __init svm_init(void) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 1f67e94..e3e056f 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1152,10 +1152,9 @@ static u64 guest_read_tsc(void) } /* - * writes 'guest_tsc' into guest's timestamp counter "register" - * guest_tsc = host_tsc + tsc_offset ==> tsc_offset = guest_tsc - host_tsc + * writes 'offset' into guest's timestamp counter offset register */ -static void vmx_write_tsc_offset(u64 offset) +static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) { vmcs_write64(TSC_OFFSET, offset); } @@ -1230,7 +1229,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) { struct vcpu_vmx *vmx = to_vmx(vcpu); struct shared_msr_entry *msr; - u64 host_tsc; int ret = 0; switch (msr_index) { @@ -1260,8 +1258,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) vmcs_writel(GUEST_SYSENTER_ESP, data); break; case MSR_IA32_TSC: - rdtscll(host_tsc); - vmx_write_tsc_offset(data - host_tsc); + kvm_write_tsc(vcpu, data); break; case MSR_IA32_CR_PAT: if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) { @@ -2659,7 +2656,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) vmx->vcpu.arch.cr4_guest_owned_bits |= X86_CR4_PGE; vmcs_writel(CR4_GUEST_HOST_MASK, ~vmx->vcpu.arch.cr4_guest_owned_bits); - vmx_write_tsc_offset(0-native_read_tsc()); + kvm_write_tsc(&vmx->vcpu, 0); return 0; } @@ -4354,6 +4351,8 @@ static struct kvm_x86_ops vmx_x86_ops = { .set_supported_cpuid = vmx_set_supported_cpuid, .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit, + + .write_tsc_offset = vmx_write_tsc_offset, }; static int __init vmx_init(void) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1bf9227..33e8208 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -895,6 +895,22 @@ static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info * static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz); +void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) +{ + struct kvm *kvm = vcpu->kvm; + u64 offset; + unsigned long flags; + + spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); + offset = data - native_read_tsc(); + kvm_x86_ops->write_tsc_offset(vcpu, offset); + spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); + + /* Reset of TSC must disable overshoot protection below */ + vcpu->arch.hv_clock.tsc_timestamp = 0; +} +EXPORT_SYMBOL_GPL(kvm_write_tsc); + static void kvm_write_guest_time(struct kvm_vcpu *v) { struct timespec ts; @@ -5495,6 +5511,8 @@ struct kvm *kvm_arch_create_vm(void) /* Reserve bit 0 of irq_sources_bitmap for userspace irq source */ set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap); + spin_lock_init(&kvm->arch.tsc_write_lock); + return kvm; } diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index b7a4047..2d6385e 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -68,4 +68,6 @@ static inline int is_paging(struct kvm_vcpu *vcpu) void kvm_before_handle_nmi(struct kvm_vcpu *vcpu); void kvm_after_handle_nmi(struct kvm_vcpu *vcpu); +void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data); + #endif -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/