Merge tag 'kvm-x86-misc-6.9' of https://github.com/kvm-x86/linux into HEAD

KVM x86 misc changes for 6.9:

 - Explicitly initialize a variety of on-stack variables in the emulator that
   triggered KMSAN false positives (though in fairness in KMSAN, it's comically
   difficult to see that the uninitialized memory is never truly consumed).

 - Fix the deubgregs ABI for 32-bit KVM, and clean up code related to reading
   DR6 and DR7.

 - Rework the "force immediate exit" code so that vendor code ultimately
   decides how and when to force the exit.  This allows VMX to further optimize
   handling preemption timer exits, and allows SVM to avoid sending a duplicate
   IPI (SVM also has a need to force an exit).

 - Fix a long-standing bug where kvm_has_noapic_vcpu could be left elevated if
   vCPU creation ultimately failed, and add WARN to guard against similar bugs.

 - Provide a dedicated arch hook for checking if a different vCPU was in-kernel
   (for directed yield), and simplify the logic for checking if the currently
   loaded vCPU is in-kernel.

 - Misc cleanups and fixes.

1 files changed, 12 insertions, 13 deletions

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e90b429c84f1..b9096bb79c00 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2735,7 +2735,6 @@ static int dr_interception(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	int reg, dr;
-	unsigned long val;
 	int err = 0;
 
 	/*
@@ -2763,11 +2762,9 @@ static int dr_interception(struct kvm_vcpu *vcpu)
 	dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
 	if (dr >= 16) { /* mov to DRn  */
 		dr -= 16;
-		val = kvm_register_read(vcpu, reg);
-		err = kvm_set_dr(vcpu, dr, val);
+		err = kvm_set_dr(vcpu, dr, kvm_register_read(vcpu, reg));
 	} else {
-		kvm_get_dr(vcpu, dr, &val);
-		kvm_register_write(vcpu, reg, val);
+		kvm_register_write(vcpu, reg, kvm_get_dr(vcpu, dr));
 	}
 
 	return kvm_complete_insn_gp(vcpu, err);
@@ -4092,6 +4089,9 @@ static int svm_vcpu_pre_run(struct kvm_vcpu *vcpu)
 
 static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
 {
+	if (is_guest_mode(vcpu))
+		return EXIT_FASTPATH_NONE;
+
 	if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
 	    to_svm(vcpu)->vmcb->control.exit_info_1)
 		return handle_fastpath_set_msr_irqoff(vcpu);
@@ -4115,12 +4115,13 @@ 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];
@@ -4139,9 +4140,12 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 		 * is enough to force an immediate vmexit.
 		 */
 		disable_nmi_singlestep(svm);
-		smp_send_reschedule(vcpu->cpu);
+		force_immediate_exit = true;
 	}
 
+	if (force_immediate_exit)
+		smp_send_reschedule(vcpu->cpu);
+
 	pre_svm_run(vcpu);
 
 	sync_lapic_to_cr8(vcpu);
@@ -4237,9 +4241,6 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 
 	svm_complete_interrupts(vcpu);
 
-	if (is_guest_mode(vcpu))
-		return EXIT_FASTPATH_NONE;
-
 	return svm_exit_handlers_fastpath(vcpu);
 }
 
@@ -4997,8 +4998,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.check_intercept = svm_check_intercept,
 	.handle_exit_irqoff = svm_handle_exit_irqoff,
 
-	.request_immediate_exit = __kvm_request_immediate_exit,
-
 	.sched_in = svm_sched_in,
 
 	.nested_ops = &svm_nested_ops,