From fcd1aa28e9dea442f74716dbd87541bf0fc11d56 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 14 Aug 2025 17:11:53 -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 555c7bf35e281..93f5237628546 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1528,7 +1528,8 @@ 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 2c0f9c7d1242d..b4283c2358a6a 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4005,12 +4005,13 @@ 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 6c1dcf44c4fa3..ab407bc00d84b 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 390af16d9a67d..0b495979a02bc 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7171,7 +7171,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, 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; @@ -7198,7 +7198,7 @@ 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 d224180c56f59..08c3da88f402b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10856,7 +10856,7 @@ 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