[6/6] KVM: x86: Fully defer to vendor code to decide how to force immediate exit

Message ID	20240110012705.506918-7-seanjc@google.com (mailing list archive)
State	New, archived
Headers	show Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C44AE32C7E for <kvm@vger.kernel.org>; Wed, 10 Jan 2024 01:27:20 +0000 (UTC) Reply-To: Sean Christopherson <seanjc@google.com> Date: Tue, 9 Jan 2024 17:27:05 -0800 In-Reply-To: <20240110012705.506918-1-seanjc@google.com> Precedence: bulk Mime-Version: 1.0 References: <20240110012705.506918-1-seanjc@google.com> Message-ID: <20240110012705.506918-7-seanjc@google.com> Subject: [PATCH 6/6] KVM: x86: Fully defer to vendor code to decide how to force immediate exit From: Sean Christopherson <seanjc@google.com> To: Sean Christopherson <seanjc@google.com>, Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Maxim Levitsky <mlevitsk@redhat.com> Content-Type: text/plain; charset="UTF-8"
Series	KVM: x86: Clean up "force immediate exit" code \| expand [0/6] KVM: x86: Clean up "force immediate exit" code [1/6] KVM: x86: Plumb "force_immediate_exit" into kvm_entry() tracepoint [2/6] KVM: VMX: Re-enter guest in fastpath for "spurious" preemption timer exits [3/6] KVM: VMX: Handle forced exit due to preemption timer in fastpath [4/6] KVM: x86: Move handling of is_guest_mode() into fastpath exit handlers [5/6] KVM: VMX: Handle KVM-induced preemption timer exits in fastpath for L2 [6/6] KVM: x86: Fully defer to vendor code to decide how to force immediate exit

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 378ed944b849..3942b74c1b75 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -103,7 +103,6 @@ KVM_X86_OP(write_tsc_multiplier) KVM_X86_OP(get_exit_info) KVM_X86_OP(check_intercept) KVM_X86_OP(handle_exit_irqoff) -KVM_X86_OP(request_immediate_exit) KVM_X86_OP(sched_in) KVM_X86_OP_OPTIONAL(update_cpu_dirty_logging) KVM_X86_OP_OPTIONAL(vcpu_blocking) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9c90664ef9fb..c48dfc142438 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1732,8 +1732,6 @@ struct kvm_x86_ops { struct x86_exception *exception); void (*handle_exit_irqoff)(struct kvm_vcpu *vcpu); - void (*request_immediate_exit)(struct kvm_vcpu *vcpu); - void (*sched_in)(struct kvm_vcpu *vcpu, int cpu); /* @@ -2239,7 +2237,6 @@ extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn); int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu); int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err); -void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu); void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index c32576c951ce..eabadbb4ffa3 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4143,8 +4143,11 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, * is enough to force an immediate vmexit. */ disable_nmi_singlestep(svm); + force_immediate_exit = true; + } + + if (force_immediate_exit) smp_send_reschedule(vcpu->cpu); - } pre_svm_run(vcpu); @@ -4998,8 +5001,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .check_intercept = svm_check_intercept, .handle_exit_irqoff = svm_handle_exit_irqoff, - .request_immediate_exit = __kvm_request_immediate_exit, - .sched_in = svm_sched_in, .nested_ops = &svm_nested_ops, diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 14658e794fbd..603412e0add3 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -49,6 +49,8 @@ #include <asm/spec-ctrl.h> #include <asm/vmx.h> +#include <trace/events/ipi.h> + #include "capabilities.h" #include "cpuid.h" #include "hyperv.h" @@ -1281,8 +1283,6 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) u16 fs_sel, gs_sel; int i; - vmx->req_immediate_exit = false; - /* * Note that guest MSRs to be saved/restored can also be changed * when guest state is loaded. This happens when guest transitions @@ -5991,7 +5991,8 @@ static int handle_pml_full(struct kvm_vcpu *vcpu) return 1; } -static fastpath_t handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu) +static fastpath_t handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu, + bool force_immediate_exit) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -6007,7 +6008,7 @@ static fastpath_t handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu) * If the timer expired because KVM used it to force an immediate exit, * then mission accomplished. */ - if (vmx->req_immediate_exit) + if (force_immediate_exit) return EXIT_FASTPATH_EXIT_HANDLED; /* @@ -7169,13 +7170,13 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) msrs[i].host, false); } -static void vmx_update_hv_timer(struct kvm_vcpu *vcpu) +static void vmx_update_hv_timer(struct kvm_vcpu *vcpu, bool force_immediate_exit) { struct vcpu_vmx *vmx = to_vmx(vcpu); u64 tscl; u32 delta_tsc; - if (vmx->req_immediate_exit) { + if (force_immediate_exit) { vmcs_write32(VMX_PREEMPTION_TIMER_VALUE, 0); vmx->loaded_vmcs->hv_timer_soft_disabled = false; } else if (vmx->hv_deadline_tsc != -1) { @@ -7228,7 +7229,8 @@ void noinstr vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx, barrier_nospec(); } -static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) +static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu, + bool force_immediate_exit) { /* * If L2 is active, some VMX preemption timer exits can be handled in @@ -7242,7 +7244,7 @@ static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) case EXIT_REASON_MSR_WRITE: return handle_fastpath_set_msr_irqoff(vcpu); case EXIT_REASON_PREEMPTION_TIMER: - return handle_fastpath_preemption_timer(vcpu); + return handle_fastpath_preemption_timer(vcpu, force_immediate_exit); default: return EXIT_FASTPATH_NONE; } @@ -7385,7 +7387,9 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit) vmx_passthrough_lbr_msrs(vcpu); if (enable_preemption_timer) - vmx_update_hv_timer(vcpu); + vmx_update_hv_timer(vcpu, force_immediate_exit); + else if (force_immediate_exit) + smp_send_reschedule(vcpu->cpu); kvm_wait_lapic_expire(vcpu); @@ -7449,7 +7453,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit) vmx_recover_nmi_blocking(vmx); vmx_complete_interrupts(vmx); - return vmx_exit_handlers_fastpath(vcpu); + return vmx_exit_handlers_fastpath(vcpu, force_immediate_exit); } static void vmx_vcpu_free(struct kvm_vcpu *vcpu) @@ -7929,11 +7933,6 @@ static __init void vmx_set_cpu_caps(void) kvm_cpu_cap_check_and_set(X86_FEATURE_WAITPKG); } -static void vmx_request_immediate_exit(struct kvm_vcpu *vcpu) -{ - to_vmx(vcpu)->req_immediate_exit = true; -} - static int vmx_check_intercept_io(struct kvm_vcpu *vcpu, struct x86_instruction_info *info) { @@ -8386,8 +8385,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = { .check_intercept = vmx_check_intercept, .handle_exit_irqoff = vmx_handle_exit_irqoff, - .request_immediate_exit = vmx_request_immediate_exit, - .sched_in = vmx_sched_in, .cpu_dirty_log_size = PML_ENTITY_NUM, @@ -8647,7 +8644,6 @@ static __init int hardware_setup(void) if (!enable_preemption_timer) { vmx_x86_ops.set_hv_timer = NULL; vmx_x86_ops.cancel_hv_timer = NULL; - vmx_x86_ops.request_immediate_exit = __kvm_request_immediate_exit; } kvm_caps.supported_mce_cap |= MCG_LMCE_P; diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index e3b0985bb74a..65786dbe7d60 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -332,8 +332,6 @@ struct vcpu_vmx { unsigned int ple_window; bool ple_window_dirty; - bool req_immediate_exit; - /* Support for PML */ #define PML_ENTITY_NUM 512 struct page *pml_pg; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e4523ca3dedf..fb9f9029ccbf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10673,12 +10673,6 @@ static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu) static_call_cond(kvm_x86_set_apic_access_page_addr)(vcpu); } -void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu) -{ - smp_send_reschedule(vcpu->cpu); -} -EXPORT_SYMBOL_GPL(__kvm_request_immediate_exit); - /* * Called within kvm->srcu read side. * Returns 1 to let vcpu_run() continue the guest execution loop without @@ -10928,10 +10922,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) goto cancel_injection; } - if (req_immediate_exit) { + if (req_immediate_exit) kvm_make_request(KVM_REQ_EVENT, vcpu); - static_call(kvm_x86_request_immediate_exit)(vcpu); - } fpregs_assert_state_consistent(); if (test_thread_flag(TIF_NEED_FPU_LOAD))

[6/6] KVM: x86: Fully defer to vendor code to decide how to force immediate exit

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