KVM/nVMX: Use kvm_vcpu_map when mapping the L1 MSR bitmap

Use kvm_vcpu_map when mapping the L1 MSR bitmap since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/nested.c

@@ -519,9 +519,10 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 						 struct vmcs12 *vmcs12)
 {
 	int msr;
-	struct page *page;
 	unsigned long *msr_bitmap_l1;
 	unsigned long *msr_bitmap_l0 = to_vmx(vcpu)->nested.vmcs02.msr_bitmap;
+	struct kvm_host_map *map = &to_vmx(vcpu)->nested.msr_bitmap_map;
+
 	/*
 	 * pred_cmd & spec_ctrl are trying to verify two things:
 	 *
@@ -547,11 +548,10 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 	    !pred_cmd && !spec_ctrl)
 		return false;
 
-	page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->msr_bitmap);
-	if (is_error_page(page))
+	if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->msr_bitmap), map))
 		return false;
 
-	msr_bitmap_l1 = (unsigned long *)kmap(page);
+	msr_bitmap_l1 = (unsigned long *)map->hva;
 
 	/*
 	 * To keep the control flow simple, pay eight 8-byte writes (sixteen
@@ -604,8 +604,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 					MSR_IA32_PRED_CMD,
 					MSR_TYPE_W);
 
-	kunmap(page);
-	kvm_release_page_clean(page);
+	kvm_vcpu_unmap(vcpu, &to_vmx(vcpu)->nested.msr_bitmap_map, false);
 
 	return true;
 }

arch/x86/kvm/vmx/vmx.h

@@ -144,6 +144,9 @@ struct nested_vmx {
 	struct page *apic_access_page;
 	struct page *virtual_apic_page;
 	struct page *pi_desc_page;
+
+	struct kvm_host_map msr_bitmap_map;
+
 	struct pi_desc *pi_desc;
 	bool pi_pending;
 	u16 posted_intr_nv;