KVM: nVMX: Introduce accessor to get Hyper-V eVMCS pointer

There's a number of 'vmx->nested.hv_evmcs' accesses in nested.c, introduce
'nested_vmx_evmcs()' accessor to hide them all in !CONFIG_KVM_HYPERV case.

No functional change intended.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20231205103630.1391318-15-vkuznets@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: vittyvk

arch/x86/kvm/vmx/hyperv.h

@@ -37,6 +37,11 @@ static inline bool nested_vmx_is_evmptr12_set(struct vcpu_vmx *vmx)
 	return evmptr_is_set(vmx->nested.hv_evmcs_vmptr);
 }
 
+static inline struct hv_enlightened_vmcs *nested_vmx_evmcs(struct vcpu_vmx *vmx)
+{
+	return vmx->nested.hv_evmcs;
+}
+
 static inline bool guest_cpuid_has_evmcs(struct kvm_vcpu *vcpu)
 {
 	/*
@@ -75,6 +80,11 @@ static inline bool nested_vmx_is_evmptr12_set(struct vcpu_vmx *vmx)
 {
 	return false;
 }
+
+static inline struct hv_enlightened_vmcs *nested_vmx_evmcs(struct vcpu_vmx *vmx)
+{
+	return NULL;
+}
 #endif
 
 #endif /* __KVM_X86_VMX_HYPERV_H */

arch/x86/kvm/vmx/nested.c

@@ -263,7 +263,7 @@ static bool nested_evmcs_handle_vmclear(struct kvm_vcpu *vcpu, gpa_t vmptr)
 	    !evmptr_is_valid(nested_get_evmptr(vcpu)))
 		return false;
 
-	if (vmx->nested.hv_evmcs && vmptr == vmx->nested.hv_evmcs_vmptr)
+	if (nested_vmx_evmcs(vmx) && vmptr == vmx->nested.hv_evmcs_vmptr)
 		nested_release_evmcs(vcpu);
 
 	return true;
@@ -601,7 +601,6 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 	int msr;
 	unsigned long *msr_bitmap_l1;
 	unsigned long *msr_bitmap_l0 = vmx->nested.vmcs02.msr_bitmap;
-	struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
 	struct kvm_host_map *map = &vmx->nested.msr_bitmap_map;
 
 	/* Nothing to do if the MSR bitmap is not in use.  */
@@ -617,10 +616,13 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 	 * - Nested hypervisor (L1) has enabled 'Enlightened MSR Bitmap' feature
 	 *   and tells KVM (L0) there were no changes in MSR bitmap for L2.
 	 */
-	if (!vmx->nested.force_msr_bitmap_recalc && evmcs &&
-	    evmcs->hv_enlightenments_control.msr_bitmap &&
-	    evmcs->hv_clean_fields & HV_VMX_ENLIGHTENED_CLEAN_FIELD_MSR_BITMAP)
-		return true;
+	if (!vmx->nested.force_msr_bitmap_recalc) {
+		struct hv_enlightened_vmcs *evmcs = nested_vmx_evmcs(vmx);
+
+		if (evmcs && evmcs->hv_enlightenments_control.msr_bitmap &&
+		    evmcs->hv_clean_fields & HV_VMX_ENLIGHTENED_CLEAN_FIELD_MSR_BITMAP)
+			return true;
+	}
 
 	if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->msr_bitmap), map))
 		return false;
@@ -1603,7 +1605,7 @@ static void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields
 {
 #ifdef CONFIG_KVM_HYPERV
 	struct vmcs12 *vmcs12 = vmx->nested.cached_vmcs12;
-	struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
+	struct hv_enlightened_vmcs *evmcs = nested_vmx_evmcs(vmx);
 	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(&vmx->vcpu);
 
 	/* HV_VMX_ENLIGHTENED_CLEAN_FIELD_NONE */
@@ -1851,7 +1853,7 @@ static void copy_vmcs12_to_enlightened(struct vcpu_vmx *vmx)
 {
 #ifdef CONFIG_KVM_HYPERV
 	struct vmcs12 *vmcs12 = vmx->nested.cached_vmcs12;
-	struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
+	struct hv_enlightened_vmcs *evmcs = nested_vmx_evmcs(vmx);
 
 	/*
 	 * Should not be changed by KVM:
@@ -2438,7 +2440,7 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
 
 static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 {
-	struct hv_enlightened_vmcs *hv_evmcs = vmx->nested.hv_evmcs;
+	struct hv_enlightened_vmcs *hv_evmcs = nested_vmx_evmcs(vmx);
 
 	if (!hv_evmcs || !(hv_evmcs->hv_clean_fields &
 			   HV_VMX_ENLIGHTENED_CLEAN_FIELD_GUEST_GRP2)) {
@@ -2570,15 +2572,15 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 			  enum vm_entry_failure_code *entry_failure_code)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct hv_enlightened_vmcs *evmcs = nested_vmx_evmcs(vmx);
 	bool load_guest_pdptrs_vmcs12 = false;
 
 	if (vmx->nested.dirty_vmcs12 || nested_vmx_is_evmptr12_valid(vmx)) {
 		prepare_vmcs02_rare(vmx, vmcs12);
 		vmx->nested.dirty_vmcs12 = false;
 
 		load_guest_pdptrs_vmcs12 = !nested_vmx_is_evmptr12_valid(vmx) ||
-			!(vmx->nested.hv_evmcs->hv_clean_fields &
-			  HV_VMX_ENLIGHTENED_CLEAN_FIELD_GUEST_GRP1);
+			!(evmcs->hv_clean_fields & HV_VMX_ENLIGHTENED_CLEAN_FIELD_GUEST_GRP1);
 	}
 
 	if (vmx->nested.nested_run_pending &&
@@ -2700,8 +2702,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 	 * here.
 	 */
 	if (nested_vmx_is_evmptr12_valid(vmx))
-		vmx->nested.hv_evmcs->hv_clean_fields |=
-			HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL;
+		evmcs->hv_clean_fields |= HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL;
 
 	return 0;
 }
@@ -3626,7 +3627,9 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 		return nested_vmx_failInvalid(vcpu);
 
 	if (nested_vmx_is_evmptr12_valid(vmx)) {
-		copy_enlightened_to_vmcs12(vmx, vmx->nested.hv_evmcs->hv_clean_fields);
+		struct hv_enlightened_vmcs *evmcs = nested_vmx_evmcs(vmx);
+
+		copy_enlightened_to_vmcs12(vmx, evmcs->hv_clean_fields);
 		/* Enlightened VMCS doesn't have launch state */
 		vmcs12->launch_state = !launch;
 	} else if (enable_shadow_vmcs) {
@@ -5428,7 +5431,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
 			return nested_vmx_fail(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
 
 		/* Read the field, zero-extended to a u64 value */
-		value = evmcs_read_any(vmx->nested.hv_evmcs, field, offset);
+		value = evmcs_read_any(nested_vmx_evmcs(vmx), field, offset);
 	}
 
 	/*