diff options
| -rw-r--r-- | kernel/arch/x86/include/asm/kvm_host.h | 2 | ||||
| -rw-r--r-- | kernel/arch/x86/kvm/vmx.c | 180 | ||||
| -rw-r--r-- | kernel/arch/x86/kvm/x86.c | 3 |
3 files changed, 183 insertions, 2 deletions
diff --git a/kernel/arch/x86/include/asm/kvm_host.h b/kernel/arch/x86/include/asm/kvm_host.h index 21637c9e9..fe68e836e 100644 --- a/kernel/arch/x86/include/asm/kvm_host.h +++ b/kernel/arch/x86/include/asm/kvm_host.h @@ -983,6 +983,8 @@ extern u32 kvm_max_guest_tsc_khz; extern u8 kvm_tsc_scaling_ratio_frac_bits; /* maximum allowed value of TSC scaling ratio */ extern u64 kvm_max_tsc_scaling_ratio; +/* 1ull << kvm_tsc_scaling_ratio_frac_bits */ +extern u64 kvm_default_tsc_scaling_ratio; enum emulation_result { EMULATE_DONE, /* no further processing */ diff --git a/kernel/arch/x86/kvm/vmx.c b/kernel/arch/x86/kvm/vmx.c index 073211105..e378975f5 100644 --- a/kernel/arch/x86/kvm/vmx.c +++ b/kernel/arch/x86/kvm/vmx.c @@ -109,6 +109,13 @@ module_param_named(pml, enable_pml, bool, S_IRUGO); #define KVM_VMX_TSC_MULTIPLIER_MAX 0xffffffffffffffffULL +/* Guest_tsc -> host_tsc conversion requires 64-bit division. */ +static int __read_mostly cpu_preemption_timer_multi; +static bool __read_mostly enable_preemption_timer = 1; +#ifdef CONFIG_X86_64 +module_param_named(preemption_timer, enable_preemption_timer, bool, S_IRUGO); +#endif + #define KVM_GUEST_CR0_MASK (X86_CR0_NW | X86_CR0_CD) #define KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST (X86_CR0_WP | X86_CR0_NE) #define KVM_VM_CR0_ALWAYS_ON \ @@ -596,6 +603,9 @@ struct vcpu_vmx { #define PML_ENTITY_NUM 512 struct page *pml_pg; + /* apic deadline value in host tsc */ + u64 hv_deadline_tsc; + u64 current_tsc_ratio; }; @@ -1043,6 +1053,61 @@ static inline bool cpu_has_vmx_virtual_intr_delivery(void) SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY; } +/* + * Comment's format: document - errata name - stepping - processor name. + * Refer from + * https://www.virtualbox.org/svn/vbox/trunk/src/VBox/VMM/VMMR0/HMR0.cpp + */ +static u32 vmx_preemption_cpu_tfms[] = { +/* 323344.pdf - BA86 - D0 - Xeon 7500 Series */ +0x000206E6, +/* 323056.pdf - AAX65 - C2 - Xeon L3406 */ +/* 322814.pdf - AAT59 - C2 - i7-600, i5-500, i5-400 and i3-300 Mobile */ +/* 322911.pdf - AAU65 - C2 - i5-600, i3-500 Desktop and Pentium G6950 */ +0x00020652, +/* 322911.pdf - AAU65 - K0 - i5-600, i3-500 Desktop and Pentium G6950 */ +0x00020655, +/* 322373.pdf - AAO95 - B1 - Xeon 3400 Series */ +/* 322166.pdf - AAN92 - B1 - i7-800 and i5-700 Desktop */ +/* + * 320767.pdf - AAP86 - B1 - + * i7-900 Mobile Extreme, i7-800 and i7-700 Mobile + */ +0x000106E5, +/* 321333.pdf - AAM126 - C0 - Xeon 3500 */ +0x000106A0, +/* 321333.pdf - AAM126 - C1 - Xeon 3500 */ +0x000106A1, +/* 320836.pdf - AAJ124 - C0 - i7-900 Desktop Extreme and i7-900 Desktop */ +0x000106A4, + /* 321333.pdf - AAM126 - D0 - Xeon 3500 */ + /* 321324.pdf - AAK139 - D0 - Xeon 5500 */ + /* 320836.pdf - AAJ124 - D0 - i7-900 Extreme and i7-900 Desktop */ +0x000106A5, +}; + +static inline bool cpu_has_broken_vmx_preemption_timer(void) +{ + u32 eax = cpuid_eax(0x00000001), i; + + /* Clear the reserved bits */ + eax &= ~(0x3U << 14 | 0xfU << 28); + for (i = 0; i < sizeof(vmx_preemption_cpu_tfms)/sizeof(u32); i++) + if (eax == vmx_preemption_cpu_tfms[i]) + return true; + + return false; +} + +static inline bool cpu_has_vmx_preemption_timer(void) +{ + if (cpu_has_broken_vmx_preemption_timer()) + return false; + + return vmcs_config.pin_based_exec_ctrl & + PIN_BASED_VMX_PREEMPTION_TIMER; +} + static inline bool cpu_has_vmx_posted_intr(void) { return IS_ENABLED(CONFIG_X86_LOCAL_APIC) && @@ -3209,7 +3274,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) return -EIO; min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING; - opt = PIN_BASED_VIRTUAL_NMIS | PIN_BASED_POSTED_INTR; + opt = PIN_BASED_VIRTUAL_NMIS | PIN_BASED_POSTED_INTR | + PIN_BASED_VMX_PREEMPTION_TIMER; if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS, &_pin_based_exec_control) < 0) return -EIO; @@ -4683,6 +4749,8 @@ static u32 vmx_pin_based_exec_ctrl(struct vcpu_vmx *vmx) if (!vmx_cpu_uses_apicv(&vmx->vcpu)) pin_based_exec_ctrl &= ~PIN_BASED_POSTED_INTR; + /* Enable the preemption timer dynamically */ + pin_based_exec_ctrl &= ~PIN_BASED_VMX_PREEMPTION_TIMER; return pin_based_exec_ctrl; } @@ -4781,6 +4849,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) /* Control */ vmcs_write32(PIN_BASED_VM_EXEC_CONTROL, vmx_pin_based_exec_ctrl(vmx)); + vmx->hv_deadline_tsc = -1; vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, vmx_exec_control(vmx)); @@ -6292,6 +6361,17 @@ static __init int hardware_setup(void) kvm_x86_ops->enable_log_dirty_pt_masked = NULL; } + if (cpu_has_vmx_preemption_timer() && enable_preemption_timer) { + u64 vmx_msr; + + rdmsrl(MSR_IA32_VMX_MISC, vmx_msr); + cpu_preemption_timer_multi = + vmx_msr & VMX_MISC_PREEMPTION_TIMER_RATE_MASK; + } else { + kvm_x86_ops->set_hv_timer = NULL; + kvm_x86_ops->cancel_hv_timer = NULL; + } + kvm_set_posted_intr_wakeup_handler(wakeup_handler); return alloc_kvm_area(); @@ -7460,6 +7540,12 @@ static int handle_pcommit(struct kvm_vcpu *vcpu) return 1; } +static int handle_preemption_timer(struct kvm_vcpu *vcpu) +{ + kvm_lapic_expired_hv_timer(vcpu); + return 1; +} + /* * The exit handlers return 1 if the exit was handled fully and guest execution * may resume. Otherwise they set the kvm_run parameter to indicate what needs @@ -7511,6 +7597,7 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { [EXIT_REASON_XRSTORS] = handle_xrstors, [EXIT_REASON_PML_FULL] = handle_pml_full, [EXIT_REASON_PCOMMIT] = handle_pcommit, + [EXIT_REASON_PREEMPTION_TIMER] = handle_preemption_timer, }; static const int kvm_vmx_max_exit_handlers = @@ -8510,6 +8597,26 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) msrs[i].host); } +void vmx_arm_hv_timer(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + u64 tscl; + u32 delta_tsc; + + if (vmx->hv_deadline_tsc == -1) + return; + + tscl = rdtsc(); + if (vmx->hv_deadline_tsc > tscl) + /* sure to be 32 bit only because checked on set_hv_timer */ + delta_tsc = (u32)((vmx->hv_deadline_tsc - tscl) >> + cpu_preemption_timer_multi); + else + delta_tsc = 0; + + vmcs_write32(VMX_PREEMPTION_TIMER_VALUE, delta_tsc); +} + static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -8556,6 +8663,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) atomic_switch_perf_msrs(vmx); debugctlmsr = get_debugctlmsr(); + vmx_arm_hv_timer(vcpu); + vmx->__launched = vmx->loaded_vmcs->launched; asm( /* Store host registers */ @@ -10532,6 +10641,64 @@ static int vmx_check_intercept(struct kvm_vcpu *vcpu, return X86EMUL_CONTINUE; } +#ifdef CONFIG_X86_64 +/* (a << shift) / divisor, return 1 if overflow otherwise 0 */ +static inline int u64_shl_div_u64(u64 a, unsigned int shift, + u64 divisor, u64 *result) +{ + u64 low = a << shift, high = a >> (64 - shift); + + /* To avoid the overflow on divq */ + if (high >= divisor) + return 1; + + /* Low hold the result, high hold rem which is discarded */ + asm("divq %2\n\t" : "=a" (low), "=d" (high) : + "rm" (divisor), "0" (low), "1" (high)); + *result = low; + + return 0; +} + +static int vmx_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + u64 tscl = rdtsc(), delta_tsc; + + delta_tsc = guest_deadline_tsc - kvm_read_l1_tsc(vcpu, tscl); + + /* Convert to host delta tsc if tsc scaling is enabled */ + if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio && + u64_shl_div_u64(delta_tsc, + kvm_tsc_scaling_ratio_frac_bits, + vcpu->arch.tsc_scaling_ratio, + &delta_tsc)) + return -ERANGE; + + /* + * If the delta tsc can't fit in the 32 bit after the multi shift, + * we can't use the preemption timer. + * It's possible that it fits on later vmentries, but checking + * on every vmentry is costly so we just use an hrtimer. + */ + if (delta_tsc >> (cpu_preemption_timer_multi + 32)) + return -ERANGE; + + vmx->hv_deadline_tsc = tscl + delta_tsc; + vmcs_set_bits(PIN_BASED_VM_EXEC_CONTROL, + PIN_BASED_VMX_PREEMPTION_TIMER); + return 0; +} + +static void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + vmx->hv_deadline_tsc = -1; + vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL, + PIN_BASED_VMX_PREEMPTION_TIMER); +} +#endif + static void vmx_sched_in(struct kvm_vcpu *vcpu, int cpu) { if (ple_gap) @@ -10647,6 +10814,9 @@ static int vmx_pre_block(struct kvm_vcpu *vcpu) if (pi_pre_block(vcpu)) return 1; + if (kvm_lapic_hv_timer_in_use(vcpu)) + kvm_lapic_switch_to_sw_timer(vcpu); + return 0; } @@ -10693,6 +10863,9 @@ static void pi_post_block(struct kvm_vcpu *vcpu) static void vmx_post_block(struct kvm_vcpu *vcpu) { + if (kvm_x86_ops->set_hv_timer) + kvm_lapic_switch_to_hv_timer(vcpu); + pi_post_block(vcpu); } @@ -10891,6 +11064,11 @@ static struct kvm_x86_ops vmx_x86_ops = { .pmu_ops = &intel_pmu_ops, .update_pi_irte = vmx_update_pi_irte, + +#ifdef CONFIG_X86_64 + .set_hv_timer = vmx_set_hv_timer, + .cancel_hv_timer = vmx_cancel_hv_timer, +#endif }; static int __init vmx_init(void) diff --git a/kernel/arch/x86/kvm/x86.c b/kernel/arch/x86/kvm/x86.c index e3e1a8c1b..c7695cea4 100644 --- a/kernel/arch/x86/kvm/x86.c +++ b/kernel/arch/x86/kvm/x86.c @@ -113,7 +113,8 @@ u8 __read_mostly kvm_tsc_scaling_ratio_frac_bits; EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_frac_bits); u64 __read_mostly kvm_max_tsc_scaling_ratio; EXPORT_SYMBOL_GPL(kvm_max_tsc_scaling_ratio); -static u64 __read_mostly kvm_default_tsc_scaling_ratio; +u64 __read_mostly kvm_default_tsc_scaling_ratio; +EXPORT_SYMBOL_GPL(kvm_default_tsc_scaling_ratio); /* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */ static u32 __read_mostly tsc_tolerance_ppm = 250; |