From e48672fa25e879f7ae21785c7efd187738139593 Mon Sep 17 00:00:00 2001 From: Zachary Amsden Date: Thu, 19 Aug 2010 22:07:23 -1000 Subject: [PATCH] KVM: x86: Unify TSC logic Move the TSC control logic from the vendor backends into x86.c by adding adjust_tsc_offset to x86 ops. Now all TSC decisions can be done in one place. Signed-off-by: Zachary Amsden Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/kvm_host.h | 5 +++-- arch/x86/kvm/svm.c | 26 ++++++++++---------------- arch/x86/kvm/vmx.c | 22 ++++++++-------------- arch/x86/kvm/x86.c | 17 ++++++++++++++--- 4 files changed, 35 insertions(+), 35 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 57b4394..5ab1c3f 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 ea41c55..ff28f65 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -715,6 +715,15 @@ 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; @@ -961,20 +970,6 @@ 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; } @@ -990,8 +985,6 @@ 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) @@ -3553,6 +3546,7 @@ 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 138746d..275a81d 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; @@ -881,7 +880,6 @@ 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) @@ -898,14 +896,12 @@ 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. @@ -915,16 +911,6 @@ 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); - } } } @@ -1153,6 +1139,12 @@ 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. @@ -4108,6 +4100,7 @@ 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(); @@ -4347,6 +4340,7 @@ 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 a8dee58..468fafa 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) -- 2.7.4