From: Sean Christopherson <seanjc@google.com>
To: stable@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sasha Levin <sashal@kernel.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 6.1.y 09/21] KVM: x86: Plumb "force_immediate_exit" into kvm_entry() tracepoint
Date: Thu, 14 Aug 2025 17:11:53 -0700 [thread overview]
Message-ID: <20250815001205.2370711-10-seanjc@google.com> (raw)
In-Reply-To: <20250815001205.2370711-1-seanjc@google.com>
[ 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 <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20240110012705.506918-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
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 555c7bf35e28..93f523762854 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 2c0f9c7d1242..b4283c2358a6 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 6c1dcf44c4fa..ab407bc00d84 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 390af16d9a67..0b495979a02b 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 e7c73360890d..652f90ad7107 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;
--
2.51.0.rc1.163.g2494970778-goog
next prev parent reply other threads:[~2025-08-15 0:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-15 0:11 [PATCH 6.1.y 00/21] KVM: x86: Backports for 6.1.y Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 01/21] KVM: SVM: Set RFLAGS.IF=1 in C code, to get VMRUN out of the STI shadow Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 02/21] KVM: x86: Re-split x2APIC ICR into ICR+ICR2 for AMD (x2AVIC) Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 03/21] KVM: x86: Plumb in the vCPU to kvm_x86_ops.hwapic_isr_update() Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 04/21] KVM: nVMX: Defer SVI update to vmcs01 on EOI when L2 is active w/o VID Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 05/21] KVM: x86: Take irqfds.lock when adding/deleting IRQ bypass producer Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 06/21] KVM: x86: Snapshot the host's DEBUGCTL in common x86 Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 07/21] KVM: x86: Snapshot the host's DEBUGCTL after disabling IRQs Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 08/21] KVM: x86/pmu: Gate all "unimplemented MSR" prints on report_ignored_msrs Sean Christopherson
2025-08-15 0:11 ` Sean Christopherson [this message]
2025-08-15 0:11 ` [PATCH 6.1.y 10/21] KVM: VMX: Re-enter guest in fastpath for "spurious" preemption timer exits Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 11/21] KVM: VMX: Handle forced exit due to preemption timer in fastpath Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 12/21] KVM: x86: Move handling of is_guest_mode() into fastpath exit handlers Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 13/21] KVM: VMX: Handle KVM-induced preemption timer exits in fastpath for L2 Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 14/21] KVM: x86: Fully defer to vendor code to decide how to force immediate exit Sean Christopherson
2025-08-15 0:11 ` [PATCH 6.1.y 15/21] KVM: x86: Convert vcpu_run()'s immediate exit param into a generic bitmap Sean Christopherson
2025-08-15 0:12 ` [PATCH 6.1.y 16/21] KVM: x86: Drop kvm_x86_ops.set_dr6() in favor of a new KVM_RUN flag Sean Christopherson
2025-08-15 0:12 ` [PATCH 6.1.y 17/21] KVM: VMX: Allow guest to set DEBUGCTL.RTM_DEBUG if RTM is supported Sean Christopherson
2025-08-15 0:12 ` [PATCH 6.1.y 18/21] KVM: VMX: Extract checking of guest's DEBUGCTL into helper Sean Christopherson
2025-08-15 0:12 ` [PATCH 6.1.y 19/21] KVM: nVMX: Check vmcs12->guest_ia32_debugctl on nested VM-Enter Sean Christopherson
2025-08-15 0:12 ` [PATCH 6.1.y 20/21] KVM: VMX: Wrap all accesses to IA32_DEBUGCTL with getter/setter APIs Sean Christopherson
2025-08-15 0:12 ` [PATCH 6.1.y 21/21] KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while running the guest Sean Christopherson
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