Re: [RFC PATCH v6 2/6] KVM: x86: Move *_in_guest power management flags to vCPU scope

Zhi Wang
2023-02-02T14:57:14Z

On Sat, 21 Jan 2023 02:07:34 +0000
Kechen Lu <kechenl@nvidia.com> wrote:

> Make the runtime disabled mwait/hlt/pause/cstate exits flags vCPU scope
> to allow finer-grained, per-vCPU control. The VM-scoped control is only
> allowed before vCPUs are created, thus preserving the existing behavior
> is a simple matter of snapshotting the flags at vCPU creation.
>
> Signed-off-by: Kechen Lu <kechenl@nvidia.com>
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Reviewed-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/include/asm/kvm_host.h | 5 +++++
> arch/x86/kvm/cpuid.c | 4 ++--
> arch/x86/kvm/lapic.c | 7 +++----
> arch/x86/kvm/svm/nested.c | 4 ++--
> arch/x86/kvm/svm/svm.c | 12 ++++++------
> arch/x86/kvm/vmx/vmx.c | 16 ++++++++--------
> arch/x86/kvm/x86.c | 6 +++++-
> arch/x86/kvm/x86.h | 16 ++++++++--------
> 8 files changed, 39 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 6aaae18f1854..41b998234a04 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1009,6 +1009,11 @@ struct kvm_vcpu_arch {
> #if IS_ENABLED(CONFIG_HYPERV)
> hpa_t hv_root_tdp;
> #endif
> +
> + bool mwait_in_guest;
> + bool hlt_in_guest;
> + bool pause_in_guest;
> + bool cstate_in_guest;

Better add some comments here. When xxx_in_guest stays together with
XXX_DISABLE_EXIT_XXX, it can be quite confusing. Or maybe align the naming
like bool disable_exit_mwait <-> XXX_DISABLE_EXIT_XXX.

> };
>
> struct kvm_lpage_info {
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 596061c1610e..20e427dc608c 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -283,8 +283,8 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e
> best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
>
> best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent);
> - if (kvm_hlt_in_guest(vcpu->kvm) && best &&
> - (best->eax & (1 << KVM_FEATURE_PV_UNHALT)))
> + if (kvm_hlt_in_guest(vcpu) &&
> + best && (best->eax & (1 << KVM_FEATURE_PV_UNHALT)))
> best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT);
>
> if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT)) {
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 4efdb4a4d72c..f0f49d0c6e69 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -151,14 +151,13 @@ static inline u32 kvm_x2apic_id(struct kvm_lapic *apic)
> static bool kvm_can_post_timer_interrupt(struct kvm_vcpu *vcpu)
> {
> return pi_inject_timer && kvm_vcpu_apicv_active(vcpu) &&
> - (kvm_mwait_in_guest(vcpu->kvm) || kvm_hlt_in_guest(vcpu->kvm));
> + (kvm_mwait_in_guest(vcpu) || kvm_hlt_in_guest(vcpu));
> }
>
> bool kvm_can_use_hv_timer(struct kvm_vcpu *vcpu)
> {
> - return kvm_x86_ops.set_hv_timer
> - && !(kvm_mwait_in_guest(vcpu->kvm) ||
> - kvm_can_post_timer_interrupt(vcpu));
> + return kvm_x86_ops.set_hv_timer &&
> + !(kvm_mwait_in_guest(vcpu) || kvm_can_post_timer_interrupt(vcpu));
> }
>
> static bool kvm_use_posted_timer_interrupt(struct kvm_vcpu *vcpu)
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index add65dd59756..ed26b6de3007 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -721,7 +721,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
>
> pause_count12 = svm->pause_filter_enabled ? svm->nested.ctl.pause_filter_count : 0;
> pause_thresh12 = svm->pause_threshold_enabled ? svm->nested.ctl.pause_filter_thresh : 0;
> - if (kvm_pause_in_guest(svm->vcpu.kvm)) {
> + if (kvm_pause_in_guest(&svm->vcpu)) {
> /* use guest values since host doesn't intercept PAUSE */
> vmcb02->control.pause_filter_count = pause_count12;
> vmcb02->control.pause_filter_thresh = pause_thresh12;
> @@ -1012,7 +1012,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
> vmcb12->control.event_inj = svm->nested.ctl.event_inj;
> vmcb12->control.event_inj_err = svm->nested.ctl.event_inj_err;
>
> - if (!kvm_pause_in_guest(vcpu->kvm)) {
> + if (!kvm_pause_in_guest(vcpu)) {
> vmcb01->control.pause_filter_count = vmcb02->control.pause_filter_count;
> vmcb_mark_dirty(vmcb01, VMCB_INTERCEPTS);
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 9a194aa1a75a..dc7176605e01 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -1014,7 +1014,7 @@ static void grow_ple_window(struct kvm_vcpu *vcpu)
> struct vmcb_control_area *control = &svm->vmcb->control;
> int old = control->pause_filter_count;
>
> - if (kvm_pause_in_guest(vcpu->kvm))
> + if (kvm_pause_in_guest(vcpu))
> return;
>
> control->pause_filter_count = __grow_ple_window(old,
> @@ -1035,7 +1035,7 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu)
> struct vmcb_control_area *control = &svm->vmcb->control;
> int old = control->pause_filter_count;
>
> - if (kvm_pause_in_guest(vcpu->kvm))
> + if (kvm_pause_in_guest(vcpu))
> return;
>
> control->pause_filter_count =
> @@ -1229,12 +1229,12 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
> svm_set_intercept(svm, INTERCEPT_RDPRU);
> svm_set_intercept(svm, INTERCEPT_RSM);
>
> - if (!kvm_mwait_in_guest(vcpu->kvm)) {
> + if (!kvm_mwait_in_guest(vcpu)) {
> svm_set_intercept(svm, INTERCEPT_MONITOR);
> svm_set_intercept(svm, INTERCEPT_MWAIT);
> }
>
> - if (!kvm_hlt_in_guest(vcpu->kvm))
> + if (!kvm_hlt_in_guest(vcpu))
> svm_set_intercept(svm, INTERCEPT_HLT);
>
> control->iopm_base_pa = __sme_set(iopm_base);
> @@ -1278,7 +1278,7 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
> svm->nested.vmcb12_gpa = INVALID_GPA;
> svm->nested.last_vmcb12_gpa = INVALID_GPA;
>
> - if (!kvm_pause_in_guest(vcpu->kvm)) {
> + if (!kvm_pause_in_guest(vcpu)) {
> control->pause_filter_count = pause_filter_count;
> if (pause_filter_thresh)
> control->pause_filter_thresh = pause_filter_thresh;
> @@ -4362,7 +4362,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
>
> static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
> {
> - if (!kvm_pause_in_guest(vcpu->kvm))
> + if (!kvm_pause_in_guest(vcpu))
> shrink_ple_window(vcpu);
> }
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index fc9008dbed33..019a20029878 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1689,7 +1689,7 @@ static void vmx_clear_hlt(struct kvm_vcpu *vcpu)
> * then the instruction is already executing and RIP has already been
> * advanced.
> */
> - if (kvm_hlt_in_guest(vcpu->kvm) &&
> + if (kvm_hlt_in_guest(vcpu) &&
> vmcs_read32(GUEST_ACTIVITY_STATE) == GUEST_ACTIVITY_HLT)
> vmcs_write32(GUEST_ACTIVITY_STATE, GUEST_ACTIVITY_ACTIVE);
> }
> @@ -4412,10 +4412,10 @@ static u32 vmx_exec_control(struct vcpu_vmx *vmx)
> exec_control &= ~(CPU_BASED_CR3_LOAD_EXITING |
> CPU_BASED_CR3_STORE_EXITING |
> CPU_BASED_INVLPG_EXITING);
> - if (kvm_mwait_in_guest(vmx->vcpu.kvm))
> + if (kvm_mwait_in_guest(&vmx->vcpu))
> exec_control &= ~(CPU_BASED_MWAIT_EXITING |
> CPU_BASED_MONITOR_EXITING);
> - if (kvm_hlt_in_guest(vmx->vcpu.kvm))
> + if (kvm_hlt_in_guest(&vmx->vcpu))
> exec_control &= ~CPU_BASED_HLT_EXITING;
> return exec_control;
> }
> @@ -4515,7 +4515,7 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx)
> }
> if (!enable_unrestricted_guest)
> exec_control &= ~SECONDARY_EXEC_UNRESTRICTED_GUEST;
> - if (kvm_pause_in_guest(vmx->vcpu.kvm))
> + if (kvm_pause_in_guest(&vmx->vcpu))
> exec_control &= ~SECONDARY_EXEC_PAUSE_LOOP_EXITING;
> if (!kvm_vcpu_apicv_active(vcpu))
> exec_control &= ~(SECONDARY_EXEC_APIC_REGISTER_VIRT |
> @@ -4661,7 +4661,7 @@ static void init_vmcs(struct vcpu_vmx *vmx)
> vmcs_write16(LAST_PID_POINTER_INDEX, kvm->arch.max_vcpu_ids - 1);
> }
>
> - if (!kvm_pause_in_guest(kvm)) {
> + if (!kvm_pause_in_guest(&vmx->vcpu)) {
> vmcs_write32(PLE_GAP, ple_gap);
> vmx->ple_window = ple_window;
> vmx->ple_window_dirty = true;
> @@ -5833,7 +5833,7 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu)
> */
> static int handle_pause(struct kvm_vcpu *vcpu)
> {
> - if (!kvm_pause_in_guest(vcpu->kvm))
> + if (!kvm_pause_in_guest(vcpu))
> grow_ple_window(vcpu);
>
> /*
> @@ -7379,7 +7379,7 @@ static int vmx_vcpu_create(struct kvm_vcpu *vcpu)
> vmx_disable_intercept_for_msr(vcpu, MSR_IA32_SYSENTER_CS, MSR_TYPE_RW);
> vmx_disable_intercept_for_msr(vcpu, MSR_IA32_SYSENTER_ESP, MSR_TYPE_RW);
> vmx_disable_intercept_for_msr(vcpu, MSR_IA32_SYSENTER_EIP, MSR_TYPE_RW);
> - if (kvm_cstate_in_guest(vcpu->kvm)) {
> + if (kvm_cstate_in_guest(vcpu)) {
> vmx_disable_intercept_for_msr(vcpu, MSR_CORE_C1_RES, MSR_TYPE_R);
> vmx_disable_intercept_for_msr(vcpu, MSR_CORE_C3_RESIDENCY, MSR_TYPE_R);
> vmx_disable_intercept_for_msr(vcpu, MSR_CORE_C6_RESIDENCY, MSR_TYPE_R);
> @@ -7935,7 +7935,7 @@ static void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu)
>
> static void vmx_sched_in(struct kvm_vcpu *vcpu, int cpu)
> {
> - if (!kvm_pause_in_guest(vcpu->kvm))
> + if (!kvm_pause_in_guest(vcpu))
> shrink_ple_window(vcpu);
> }
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c8ae9c4f9f08..9a77b55142c6 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11634,6 +11634,10 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> #if IS_ENABLED(CONFIG_HYPERV)
> vcpu->arch.hv_root_tdp = INVALID_PAGE;
> #endif
> + vcpu->arch.mwait_in_guest = vcpu->kvm->arch.mwait_in_guest;
> + vcpu->arch.hlt_in_guest = vcpu->kvm->arch.hlt_in_guest;
> + vcpu->arch.pause_in_guest = vcpu->kvm->arch.pause_in_guest;
> + vcpu->arch.cstate_in_guest = vcpu->kvm->arch.cstate_in_guest;
>
> r = static_call(kvm_x86_vcpu_create)(vcpu);
> if (r)
> @@ -12885,7 +12889,7 @@ bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu)
> kvm_is_exception_pending(vcpu)))
> return false;
>
> - if (kvm_hlt_in_guest(vcpu->kvm) && !kvm_can_deliver_async_pf(vcpu))
> + if (kvm_hlt_in_guest(vcpu) && !kvm_can_deliver_async_pf(vcpu))
> return false;
>
> /*
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 9de72586f406..b8e49a9d353d 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -351,24 +351,24 @@ static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
> __rem; \
> })
>
> -static inline bool kvm_mwait_in_guest(struct kvm *kvm)
> +static inline bool kvm_mwait_in_guest(struct kvm_vcpu *vcpu)
> {
> - return kvm->arch.mwait_in_guest;
> + return vcpu->arch.mwait_in_guest;
> }
>
> -static inline bool kvm_hlt_in_guest(struct kvm *kvm)
> +static inline bool kvm_hlt_in_guest(struct kvm_vcpu *vcpu)
> {
> - return kvm->arch.hlt_in_guest;
> + return vcpu->arch.hlt_in_guest;
> }
>
> -static inline bool kvm_pause_in_guest(struct kvm *kvm)
> +static inline bool kvm_pause_in_guest(struct kvm_vcpu *vcpu)
> {
> - return kvm->arch.pause_in_guest;
> + return vcpu->arch.pause_in_guest;
> }
>
> -static inline bool kvm_cstate_in_guest(struct kvm *kvm)
> +static inline bool kvm_cstate_in_guest(struct kvm_vcpu *vcpu)
> {
> - return kvm->arch.cstate_in_guest;
> + return vcpu->arch.cstate_in_guest;
> }
>
> static inline bool kvm_notify_vmexit_enabled(struct kvm *kvm)