KVM: x86: Replace .set_hflags() with dedicated .exiting_smm() helper

Replace the .set_hflags() emulator hook with a dedicated .exiting_smm(),
moving the SMM and SMM_INSIDE_NMI flag handling out of the emulator in
the process.  This is a step towards consolidating much of the logic in
kvm_smm_changed(), including the SMM hflags updates.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609185619.992058-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -2535,8 +2535,7 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 	if ((ctxt->ops->get_hflags(ctxt) & X86EMUL_SMM_INSIDE_NMI_MASK) == 0)
 		ctxt->ops->set_nmi_mask(ctxt, false);
 
-	ctxt->ops->set_hflags(ctxt, ctxt->ops->get_hflags(ctxt) &
-		~(X86EMUL_SMM_INSIDE_NMI_MASK | X86EMUL_SMM_MASK));
+	ctxt->ops->exiting_smm(ctxt);
 
 	/*
 	 * Get back to real mode, to prepare a safe state in which to load

arch/x86/kvm/kvm_emulate.h

@@ -230,7 +230,7 @@ struct x86_emulate_ops {
 	void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
 
 	unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt);
-	void (*set_hflags)(struct x86_emulate_ctxt *ctxt, unsigned hflags);
+	void (*exiting_smm)(struct x86_emulate_ctxt *ctxt);
 	int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt,
 			     const char *smstate);
 	void (*post_leave_smm)(struct x86_emulate_ctxt *ctxt);

arch/x86/kvm/x86.c

@@ -7214,11 +7214,11 @@ static unsigned emulator_get_hflags(struct x86_emulate_ctxt *ctxt)
 	return emul_to_vcpu(ctxt)->arch.hflags;
 }
 
-static void emulator_set_hflags(struct x86_emulate_ctxt *ctxt, unsigned emul_flags)
+static void emulator_exiting_smm(struct x86_emulate_ctxt *ctxt)
 {
 	struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
 
-	vcpu->arch.hflags = emul_flags;
+	vcpu->arch.hflags &= ~(HF_SMM_MASK | HF_SMM_INSIDE_NMI_MASK);
 	kvm_mmu_reset_context(vcpu);
 }
 
@@ -7284,7 +7284,7 @@ static const struct x86_emulate_ops emulate_ops = {
 	.guest_has_fxsr      = emulator_guest_has_fxsr,
 	.set_nmi_mask        = emulator_set_nmi_mask,
 	.get_hflags          = emulator_get_hflags,
-	.set_hflags          = emulator_set_hflags,
+	.exiting_smm         = emulator_exiting_smm,
 	.pre_leave_smm       = emulator_pre_leave_smm,
 	.post_leave_smm      = emulator_post_leave_smm,
 	.triple_fault        = emulator_triple_fault,