From ea26e4ec08d4727e3a9e48a6b74695861effcbd9 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 1 Nov 2016 00:39:48 +0100 Subject: KVM: x86: drop TSC offsetting kvm_x86_ops to fix KVM_GET/SET_CLOCK MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit a545ab6a0085 ("kvm: x86: add tsc_offset field to struct kvm_vcpu_arch", 2016-09-07) the offset between host and L1 TSC is cached and need not be fished out of the VMCS or VMCB. This means that we can implement adjust_tsc_offset_guest and read_l1_tsc entirely in generic code. The simplification is particularly significant for VMX code, where vmx->nested.vmcs01_tsc_offset was duplicating what is now in vcpu->arch.tsc_offset. Therefore the vmcs01_tsc_offset can be dropped completely. More importantly, this fixes KVM_GET_CLOCK/KVM_SET_CLOCK which, after commit 108b249c453d ("KVM: x86: introduce get_kvmclock_ns", 2016-09-01) called read_l1_tsc while the VMCS was not loaded. It thus returned bogus values on Intel CPUs. Fixes: 108b249c453dd7132599ab6dc7e435a7036c193f Reported-by: Roman Kagan Reviewed-by: Radim Krčmář Signed-off-by: Paolo Bonzini diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4b20f73..bdde807 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -948,7 +948,6 @@ struct kvm_x86_ops { int (*get_lpage_level)(void); bool (*rdtscp_supported)(void); bool (*invpcid_supported)(void); - void (*adjust_tsc_offset_guest)(struct kvm_vcpu *vcpu, s64 adjustment); void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3); @@ -958,8 +957,6 @@ struct kvm_x86_ops { void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset); - u64 (*read_l1_tsc)(struct kvm_vcpu *vcpu, u64 host_tsc); - void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2); int (*check_intercept)(struct kvm_vcpu *vcpu, diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f8157a3..8ca1eca 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1138,21 +1138,6 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) mark_dirty(svm->vmcb, VMCB_INTERCEPTS); } -static void svm_adjust_tsc_offset_guest(struct kvm_vcpu *vcpu, s64 adjustment) -{ - struct vcpu_svm *svm = to_svm(vcpu); - - svm->vmcb->control.tsc_offset += adjustment; - if (is_guest_mode(vcpu)) - svm->nested.hsave->control.tsc_offset += adjustment; - else - trace_kvm_write_tsc_offset(vcpu->vcpu_id, - svm->vmcb->control.tsc_offset - adjustment, - svm->vmcb->control.tsc_offset); - - mark_dirty(svm->vmcb, VMCB_INTERCEPTS); -} - static void avic_init_vmcb(struct vcpu_svm *svm) { struct vmcb *vmcb = svm->vmcb; @@ -3449,12 +3434,6 @@ static int cr8_write_interception(struct vcpu_svm *svm) return 0; } -static u64 svm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc) -{ - struct vmcb *vmcb = get_host_vmcb(to_svm(vcpu)); - return vmcb->control.tsc_offset + host_tsc; -} - static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { struct vcpu_svm *svm = to_svm(vcpu); @@ -5422,8 +5401,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = { .has_wbinvd_exit = svm_has_wbinvd_exit, .write_tsc_offset = svm_write_tsc_offset, - .adjust_tsc_offset_guest = svm_adjust_tsc_offset_guest, - .read_l1_tsc = svm_read_l1_tsc, .set_tdp_cr3 = set_tdp_cr3, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 74a4df9..754c3a7 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -421,7 +421,6 @@ struct nested_vmx { /* vmcs02_list cache of VMCSs recently used to run L2 guests */ struct list_head vmcs02_pool; int vmcs02_num; - u64 vmcs01_tsc_offset; bool change_vmcs01_virtual_x2apic_mode; /* L2 must run next, and mustn't decide to exit to L1. */ bool nested_run_pending; @@ -2605,20 +2604,6 @@ static u64 guest_read_tsc(struct kvm_vcpu *vcpu) } /* - * Like guest_read_tsc, but always returns L1's notion of the timestamp - * counter, even if a nested guest (L2) is currently running. - */ -static u64 vmx_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc) -{ - u64 tsc_offset; - - tsc_offset = is_guest_mode(vcpu) ? - to_vmx(vcpu)->nested.vmcs01_tsc_offset : - vmcs_read64(TSC_OFFSET); - return host_tsc + tsc_offset; -} - -/* * writes 'offset' into guest's timestamp counter offset register */ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) @@ -2631,7 +2616,6 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) * to the newly set TSC to get L2's TSC. */ struct vmcs12 *vmcs12; - to_vmx(vcpu)->nested.vmcs01_tsc_offset = offset; /* recalculate vmcs02.TSC_OFFSET: */ vmcs12 = get_vmcs12(vcpu); vmcs_write64(TSC_OFFSET, offset + @@ -2644,19 +2628,6 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) } } -static void vmx_adjust_tsc_offset_guest(struct kvm_vcpu *vcpu, s64 adjustment) -{ - u64 offset = vmcs_read64(TSC_OFFSET); - - vmcs_write64(TSC_OFFSET, offset + adjustment); - if (is_guest_mode(vcpu)) { - /* Even when running L2, the adjustment needs to apply to L1 */ - to_vmx(vcpu)->nested.vmcs01_tsc_offset += adjustment; - } else - trace_kvm_write_tsc_offset(vcpu->vcpu_id, offset, - offset + adjustment); -} - static bool guest_cpuid_has_vmx(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best = kvm_find_cpuid_entry(vcpu, 1, 0); @@ -10061,9 +10032,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING) vmcs_write64(TSC_OFFSET, - vmx->nested.vmcs01_tsc_offset + vmcs12->tsc_offset); + vcpu->arch.tsc_offset + vmcs12->tsc_offset); else - vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset); + vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset); if (kvm_has_tsc_control) decache_tsc_multiplier(vmx); @@ -10293,8 +10264,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) enter_guest_mode(vcpu); - vmx->nested.vmcs01_tsc_offset = vmcs_read64(TSC_OFFSET); - if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); @@ -10818,7 +10787,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, load_vmcs12_host_state(vcpu, vmcs12); /* Update any VMCS fields that might have changed while L2 ran */ - vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset); + vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset); if (vmx->hv_deadline_tsc == -1) vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL, PIN_BASED_VMX_PREEMPTION_TIMER); @@ -11339,8 +11308,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit, .write_tsc_offset = vmx_write_tsc_offset, - .adjust_tsc_offset_guest = vmx_adjust_tsc_offset_guest, - .read_l1_tsc = vmx_read_l1_tsc, .set_tdp_cr3 = vmx_set_cr3, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e954be8..3017de0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1409,7 +1409,7 @@ static u64 kvm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc) u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc) { - return kvm_x86_ops->read_l1_tsc(vcpu, kvm_scale_tsc(vcpu, host_tsc)); + return vcpu->arch.tsc_offset + kvm_scale_tsc(vcpu, host_tsc); } EXPORT_SYMBOL_GPL(kvm_read_l1_tsc); @@ -1547,7 +1547,7 @@ EXPORT_SYMBOL_GPL(kvm_write_tsc); static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu, s64 adjustment) { - kvm_x86_ops->adjust_tsc_offset_guest(vcpu, adjustment); + kvm_vcpu_write_tsc_offset(vcpu, vcpu->arch.tsc_offset + adjustment); } static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment) @@ -1555,7 +1555,7 @@ static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment) if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio) WARN_ON(adjustment < 0); adjustment = kvm_scale_tsc(vcpu, (u64) adjustment); - kvm_x86_ops->adjust_tsc_offset_guest(vcpu, adjustment); + adjust_tsc_offset_guest(vcpu, adjustment); } #ifdef CONFIG_X86_64 -- cgit v0.10.2