[PATCH 04/10] KVM/x86: Let x86_emulate_ops.set_dr() return a bool

[Juergen Gross <jgross@suse.com>]

Today x86_emulate_ops.set_dr() is returning "0" for okay and "1" in
case of an error. In order to get rid of the literal numbers, use bool
as return type for x86_emulate_ops.set_dr() and related sub-functions.

As x86_emulate_ops.set_dr() only ever returns 0 or 1, the test for its
return value less than 0 in em_dr_write() seems to be a bug. It should
probably be just a test for not 0.

No change of functionality intended.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/emulate.c          |  2 +-
 arch/x86/kvm/kvm_emulate.h      |  2 +-
 arch/x86/kvm/svm/svm.c          |  2 +-
 arch/x86/kvm/vmx/vmx.c          |  4 ++--
 arch/x86/kvm/x86.c              | 12 ++++++------
 6 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7997ed36de38..acb8353b97a4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2207,7 +2207,7 @@ bool kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
 bool kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
 bool kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
 bool kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8);
-int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val);
+bool kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val);
 unsigned long kvm_get_dr(struct kvm_vcpu *vcpu, int dr);
 unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu);
 void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw);
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 4e3da5b497b8..f5cae7335c26 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3280,7 +3280,7 @@ static int em_dr_write(struct x86_emulate_ctxt *ctxt)
 		val = ctxt->src.val & ~0U;
 
 	/* #UD condition is already handled. */
-	if (ctxt->ops->set_dr(ctxt, ctxt->modrm_reg, val) < 0)
+	if (ctxt->ops->set_dr(ctxt, ctxt->modrm_reg, val))
 		return emulate_gp(ctxt, 0);
 
 	/* Disable writeback. */
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index efc64396d717..eafc91207b45 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -212,7 +212,7 @@ struct x86_emulate_ops {
 	bool (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
 	int (*cpl)(struct x86_emulate_ctxt *ctxt);
 	ulong (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr);
-	int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
+	bool (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
 	int (*set_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
 	int (*get_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
 	int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 98bd087dda9c..7cbf4d686415 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2556,7 +2556,7 @@ static int dr_interception(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	int reg, dr;
-	int err = 0;
+	bool err = false;
 
 	/*
 	 * SEV-ES intercepts DR7 only to disable guest debugging and the guest issues a VMGEXIT
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ff0c684d9c28..365c4ce283e5 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5533,7 +5533,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 {
 	unsigned long exit_qualification;
 	int dr, dr7, reg;
-	int err = 1;
+	bool err = true;
 
 	exit_qualification = vmx_get_exit_qual(vcpu);
 	dr = exit_qualification & DEBUG_REG_ACCESS_NUM;
@@ -5580,7 +5580,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 	reg = DEBUG_REG_ACCESS_REG(exit_qualification);
 	if (exit_qualification & TYPE_MOV_FROM_DR) {
 		kvm_register_write(vcpu, reg, kvm_get_dr(vcpu, dr));
-		err = 0;
+		err = false;
 	} else {
 		err = kvm_set_dr(vcpu, dr, kvm_register_read(vcpu, reg));
 	}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 462954633c1d..e733cb923312 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1550,7 +1550,7 @@ static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu)
 	return fixed;
 }
 
-int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
+bool kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 {
 	size_t size = ARRAY_SIZE(vcpu->arch.db);
 
@@ -1563,19 +1563,19 @@ int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 	case 4:
 	case 6:
 		if (!kvm_dr6_valid(val))
-			return 1; /* #GP */
+			return true; /* #GP */
 		vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
 		break;
 	case 5:
 	default: /* 7 */
 		if (!kvm_dr7_valid(val))
-			return 1; /* #GP */
+			return true; /* #GP */
 		vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
 		kvm_update_dr7(vcpu);
 		break;
 	}
 
-	return 0;
+	return false;
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_set_dr);
 
@@ -8530,8 +8530,8 @@ static unsigned long emulator_get_dr(struct x86_emulate_ctxt *ctxt, int dr)
 	return kvm_get_dr(emul_to_vcpu(ctxt), dr);
 }
 
-static int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
-			   unsigned long value)
+static bool emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
+			    unsigned long value)
 {
 
 	return kvm_set_dr(emul_to_vcpu(ctxt), dr, value);
-- 
2.51.0