[PATCH v3 06/10] KVM: x86: Move KVM_GUESTDBG_SINGLESTEP handling into kvm_inject_emulated_db()

From: Sean Christopherson

Date: Fri May 15 2026 - 18:31:50 EST


From: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx>

Move KVM_GUESTDBG_SINGLESTEP handling from kvm_vcpu_do_singlestep() into
kvm_inject_emulated_db() to dedup the USE_HW_BP vs. SINGLESTEP logic, and
to allow for removing kvm_vcpu_do_singlestep() entirely.

No functional change intended.

Suggested-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>
Signed-off-by: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx>
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 279e2734e088..ca30a8987f2f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8994,7 +8994,7 @@ static int kvm_inject_emulated_db(struct kvm_vcpu *vcpu, unsigned long dr6)
{
struct kvm_run *kvm_run = vcpu->run;

- if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
+ if (vcpu->guest_debug & (KVM_GUESTDBG_USE_HW_BP | KVM_GUESTDBG_SINGLESTEP)) {
kvm_run->debug.arch.dr6 = dr6 | DR6_ACTIVE_LOW;
kvm_run->debug.arch.pc = kvm_get_linear_rip(vcpu);
kvm_run->debug.arch.exception = DB_VECTOR;
@@ -9279,17 +9279,7 @@ static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7,

static int kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu)
{
- struct kvm_run *kvm_run = vcpu->run;
-
- if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
- kvm_run->debug.arch.dr6 = DR6_BS | DR6_ACTIVE_LOW;
- kvm_run->debug.arch.pc = kvm_get_linear_rip(vcpu);
- kvm_run->debug.arch.exception = DB_VECTOR;
- kvm_run->exit_reason = KVM_EXIT_DEBUG;
- return 0;
- }
- kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
- return 1;
+ return kvm_inject_emulated_db(vcpu, DR6_BS);
}

int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
--
2.54.0.563.g4f69b47b94-goog