From baf9c96e4e9d6e6e59eaccbfee5387de97042f58 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 14 Aug 2025 17:25:28 -0700 Subject: [PATCH] KVM: x86: Plumb "force_immediate_exit" into kvm_entry() tracepoint [ Upstream commit 9c9025ea003a03f967affd690f39b4ef3452c0f5 ] Annotate the kvm_entry() tracepoint with "immediate exit" when KVM is forcing a VM-Exit immediately after VM-Enter, e.g. when KVM wants to inject an event but needs to first complete some other operation. Knowing that KVM is (or isn't) forcing an exit is useful information when debugging issues related to event injection. Suggested-by: Maxim Levitsky Link: https://lore.kernel.org/r/20240110012705.506918-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Sasha Levin --- arch/x86/include/asm/kvm_host.h | 3 ++- arch/x86/kvm/svm/svm.c | 5 +++-- arch/x86/kvm/trace.h | 9 ++++++--- arch/x86/kvm/vmx/vmx.c | 4 ++-- arch/x86/kvm/x86.c | 2 +- 5 files changed, 14 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b5210505abfa5..5703600a454e2 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1624,7 +1624,8 @@ struct kvm_x86_ops { void (*flush_tlb_guest)(struct kvm_vcpu *vcpu); int (*vcpu_pre_run)(struct kvm_vcpu *vcpu); - enum exit_fastpath_completion (*vcpu_run)(struct kvm_vcpu *vcpu); + enum exit_fastpath_completion (*vcpu_run)(struct kvm_vcpu *vcpu, + bool force_immediate_exit); int (*handle_exit)(struct kvm_vcpu *vcpu, enum exit_fastpath_completion exit_fastpath); int (*skip_emulated_instruction)(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index abbb84ddfe023..5a230be224d1c 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4194,12 +4194,13 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu, bool spec_ctrl_in guest_state_exit_irqoff(); } -static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) +static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, + bool force_immediate_exit) { struct vcpu_svm *svm = to_svm(vcpu); bool spec_ctrl_intercepted = msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL); - trace_kvm_entry(vcpu); + trace_kvm_entry(vcpu, force_immediate_exit); svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX]; svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP]; diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index b82e6ed4f0241..c6b4b1728006d 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -15,20 +15,23 @@ * Tracepoint for guest mode entry. */ TRACE_EVENT(kvm_entry, - TP_PROTO(struct kvm_vcpu *vcpu), - TP_ARGS(vcpu), + TP_PROTO(struct kvm_vcpu *vcpu, bool force_immediate_exit), + TP_ARGS(vcpu, force_immediate_exit), TP_STRUCT__entry( __field( unsigned int, vcpu_id ) __field( unsigned long, rip ) + __field( bool, immediate_exit ) ), TP_fast_assign( __entry->vcpu_id = vcpu->vcpu_id; __entry->rip = kvm_rip_read(vcpu); + __entry->immediate_exit = force_immediate_exit; ), - TP_printk("vcpu %u, rip 0x%lx", __entry->vcpu_id, __entry->rip) + TP_printk("vcpu %u, rip 0x%lx%s", __entry->vcpu_id, __entry->rip, + __entry->immediate_exit ? "[immediate exit]" : "") ); /* diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 9ba4baf2a9e9a..ee501871ddb03 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7312,7 +7312,7 @@ out: guest_state_exit_irqoff(); } -static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) +static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit) { struct vcpu_vmx *vmx = to_vmx(vcpu); unsigned long cr3, cr4; @@ -7339,7 +7339,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) return EXIT_FASTPATH_NONE; } - trace_kvm_entry(vcpu); + trace_kvm_entry(vcpu, force_immediate_exit); if (vmx->ple_window_dirty) { vmx->ple_window_dirty = false; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9944b32b0b308..d04066099567e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10795,7 +10795,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) WARN_ON_ONCE((kvm_vcpu_apicv_activated(vcpu) != kvm_vcpu_apicv_active(vcpu)) && (kvm_get_apic_mode(vcpu) != LAPIC_MODE_DISABLED)); - exit_fastpath = static_call(kvm_x86_vcpu_run)(vcpu); + exit_fastpath = static_call(kvm_x86_vcpu_run)(vcpu, req_immediate_exit); if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST)) break; -- 2.47.3