[PATCH v4 4/5] KVM: SVM: Turn DEBUGCTL_RESERVED_BITS into a helper

[Shivansh Dhiman <shivansh.dhiman@amd.com>]

Replace the static DEBUGCTL_RESERVED_BITS macro with a helper,
svm_get_debugctl_reserved_bits(), and plumb the vCPU into
svm_copy_vmrun_state() so it can be passed to the helper.

The vCPU argument is currently unused (marked __maybe_unused).
It'll be used by features like Bus Lock Detect.

No functional change intended.

Signed-off-by: Shivansh Dhiman <shivansh.dhiman@amd.com>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
---
Changelog:
v3 -> v4:
 * Make it a pure NFC macro-to-helper conversion, and move the
   BUS_LOCK_DETECT gating to patch 5 (Nikunj).
 * Dropped Ravi's Co-developed-by/Signed-off-by, because the
   entire BLD gating is moved to patch 5. Collected Reviewed-by
   from Nikunj.

v3:
 * New patch.
 * Replaced the static DEBUGCTL_RESERVED_BITS macro with a per-vCPU helper
   that gates the bit on guest CPUID.

---
 arch/x86/kvm/svm/nested.c | 8 ++++----
 arch/x86/kvm/svm/svm.c    | 7 +++----
 arch/x86/kvm/svm/svm.h    | 7 +++++--
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 9b1afa47c54c..dbde186ccb81 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -820,7 +820,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm)
 		 * svm_set_msr's definition of reserved bits.
 		 */
 		svm_copy_lbrs(&vmcb02->save, save);
-		vmcb02->save.dbgctl &= ~DEBUGCTL_RESERVED_BITS;
+		vmcb02->save.dbgctl &= ~svm_get_debugctl_reserved_bits(vcpu);
 	} else {
 		svm_copy_lbrs(&vmcb02->save, &vmcb01->save);
 	}
@@ -1203,7 +1203,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 }
 
 /* Copy state save area fields which are handled by VMRUN */
-void svm_copy_vmrun_state(struct vmcb_save_area *to_save,
+void svm_copy_vmrun_state(struct kvm_vcpu *vcpu, struct vmcb_save_area *to_save,
 			  struct vmcb_save_area *from_save)
 {
 	to_save->es = from_save->es;
@@ -1230,7 +1230,7 @@ void svm_copy_vmrun_state(struct vmcb_save_area *to_save,
 
 	if (kvm_cpu_cap_has(X86_FEATURE_LBRV)) {
 		svm_copy_lbrs(to_save, from_save);
-		to_save->dbgctl &= ~DEBUGCTL_RESERVED_BITS;
+		to_save->dbgctl &= ~svm_get_debugctl_reserved_bits(vcpu);
 	}
 }
 
@@ -2071,7 +2071,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 
 	svm->nested.vmcb12_gpa = kvm_state->hdr.svm.vmcb_pa;
 
-	svm_copy_vmrun_state(&svm->vmcb01.ptr->save, save);
+	svm_copy_vmrun_state(vcpu, &svm->vmcb01.ptr->save, save);
 	nested_copy_vmcb_control_to_cache(svm, ctl);
 
 	svm_switch_vmcb(svm, &svm->nested.vmcb02);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e9f2456982d4..ccf85ea79d37 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3164,7 +3164,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 			data &= ~DEBUGCTLMSR_BTF;
 		}
 
-		if (data & DEBUGCTL_RESERVED_BITS)
+		if (data & svm_get_debugctl_reserved_bits(vcpu))
 			return 1;
 
 		if (svm->vmcb->save.dbgctl == data)
@@ -5037,8 +5037,7 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)
 
 	BUILD_BUG_ON(offsetof(struct vmcb, save) != 0x400);
 
-	svm_copy_vmrun_state(map_save.hva + 0x400,
-			     &svm->vmcb01.ptr->save);
+	svm_copy_vmrun_state(vcpu, map_save.hva + 0x400, &svm->vmcb01.ptr->save);
 
 	kvm_vcpu_unmap(vcpu, &map_save);
 	return 0;
@@ -5081,7 +5080,7 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)
 	 * used during SMM (see svm_enter_smm())
 	 */
 
-	svm_copy_vmrun_state(&svm->vmcb01.ptr->save, map_save.hva + 0x400);
+	svm_copy_vmrun_state(vcpu, &svm->vmcb01.ptr->save, map_save.hva + 0x400);
 
 	/*
 	 * Enter the nested guest now
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index d52010e4de97..696f1b4b8f8f 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -783,7 +783,10 @@ BUILD_SVM_MSR_BITMAP_HELPERS(bool, test, test)
 BUILD_SVM_MSR_BITMAP_HELPERS(void, clear, __clear)
 BUILD_SVM_MSR_BITMAP_HELPERS(void, set, __set)
 
-#define DEBUGCTL_RESERVED_BITS (~DEBUGCTLMSR_LBR)
+static inline u64 svm_get_debugctl_reserved_bits(struct kvm_vcpu *vcpu __maybe_unused)
+{
+	return ~DEBUGCTLMSR_LBR;
+}
 
 /* svm.c */
 extern bool dump_invalid_vmcb;
@@ -873,7 +876,7 @@ void svm_leave_nested(struct kvm_vcpu *vcpu);
 void svm_free_nested(struct vcpu_svm *svm);
 int svm_allocate_nested(struct vcpu_svm *svm);
 int nested_svm_vmrun(struct kvm_vcpu *vcpu);
-void svm_copy_vmrun_state(struct vmcb_save_area *to_save,
+void svm_copy_vmrun_state(struct kvm_vcpu *vcpu, struct vmcb_save_area *to_save,
 			  struct vmcb_save_area *from_save);
 void svm_copy_vmloadsave_state(struct vmcb *to_vmcb, struct vmcb *from_vmcb);
 void nested_svm_vmexit(struct vcpu_svm *svm);
-- 
2.43.0