[PATCH 6.12.y 1/7] KVM: x86: Convert vcpu_run()'s immediate exit param into a generic bitmap

[Sean Christopherson <seanjc@google.com>]

[ Upstream commit 2478b1b220c49d25cb1c3f061ec4f9b351d9a131 ]

Convert kvm_x86_ops.vcpu_run()'s "force_immediate_exit" boolean parameter
into an a generic bitmap so that similar "take action" information can be
passed to vendor code without creating a pile of boolean parameters.

This will allow dropping kvm_x86_ops.set_dr6() in favor of a new flag, and
will also allow for adding similar functionality for re-loading debugctl
in the active VMCS.

Opportunistically massage the TDX WARN and comment to prepare for adding
more run_flags, all of which are expected to be mutually exclusive with
TDX, i.e. should be WARNed on.

No functional change intended.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250610232010.162191-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
[sean: drop TDX changes]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm_host.h |  6 +++++-
 arch/x86/kvm/svm/svm.c          |  4 ++--
 arch/x86/kvm/vmx/vmx.c          |  3 ++-
 arch/x86/kvm/vmx/x86_ops.h      |  2 +-
 arch/x86/kvm/x86.c              | 11 ++++++++---
 5 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0caa3293f6db..cccc8cbe72db 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1627,6 +1627,10 @@ static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode_logical)
 	return dest_mode_logical ? APIC_DEST_LOGICAL : APIC_DEST_PHYSICAL;
 }
 
+enum kvm_x86_run_flags {
+	KVM_RUN_FORCE_IMMEDIATE_EXIT	= BIT(0),
+};
+
 struct kvm_x86_ops {
 	const char *name;
 
@@ -1706,7 +1710,7 @@ struct kvm_x86_ops {
 
 	int (*vcpu_pre_run)(struct kvm_vcpu *vcpu);
 	enum exit_fastpath_completion (*vcpu_run)(struct kvm_vcpu *vcpu,
-						  bool force_immediate_exit);
+						  u64 run_flags);
 	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 1f42a71b15c0..7d1b871cfc02 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4226,9 +4226,9 @@ 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,
-					  bool force_immediate_exit)
+static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
 {
+	bool force_immediate_exit = run_flags & KVM_RUN_FORCE_IMMEDIATE_EXIT;
 	struct vcpu_svm *svm = to_svm(vcpu);
 	bool spec_ctrl_intercepted = msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL);
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9a4ebf3dfbfc..2a977cdfcd0c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7353,8 +7353,9 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
 	guest_state_exit_irqoff();
 }
 
-fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
+fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
 {
+	bool force_immediate_exit = run_flags & KVM_RUN_FORCE_IMMEDIATE_EXIT;
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	unsigned long cr3, cr4;
 
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 4aba200f435d..5e4ce13ab305 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -21,7 +21,7 @@ void vmx_vm_destroy(struct kvm *kvm);
 int vmx_vcpu_precreate(struct kvm *kvm);
 int vmx_vcpu_create(struct kvm_vcpu *vcpu);
 int vmx_vcpu_pre_run(struct kvm_vcpu *vcpu);
-fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit);
+fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags);
 void vmx_vcpu_free(struct kvm_vcpu *vcpu);
 void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
 void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 213af0fda768..44ab46f2a2d2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10711,6 +10711,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		dm_request_for_irq_injection(vcpu) &&
 		kvm_cpu_accept_dm_intr(vcpu);
 	fastpath_t exit_fastpath;
+	u64 run_flags;
 
 	bool req_immediate_exit = false;
 
@@ -10955,8 +10956,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		goto cancel_injection;
 	}
 
-	if (req_immediate_exit)
+	run_flags = 0;
+	if (req_immediate_exit) {
+		run_flags |= KVM_RUN_FORCE_IMMEDIATE_EXIT;
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
+	}
 
 	fpregs_assert_state_consistent();
 	if (test_thread_flag(TIF_NEED_FPU_LOAD))
@@ -10992,8 +10996,7 @@ 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 = kvm_x86_call(vcpu_run)(vcpu,
-						       req_immediate_exit);
+		exit_fastpath = kvm_x86_call(vcpu_run)(vcpu, run_flags);
 		if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST))
 			break;
 
@@ -11005,6 +11008,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 			break;
 		}
 
+		run_flags = 0;
+
 		/* Note, VM-Exits that go down the "slow" path are accounted below. */
 		++vcpu->stat.exits;
 	}
-- 
2.51.0.rc1.163.g2494970778-goog