KVM: MMU: Introduce kvm_pdptr_read_mmu

This function is implemented to load the pdptr pointers of
the currently running guest (l1 or l2 guest). Therefore it
takes care about the current paging mode and can read pdptrs
out of l2 guest physical memory.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/kvm_cache_regs.h

@@ -45,6 +45,13 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
 	return vcpu->arch.walk_mmu->pdptrs[index];
 }
 
+static inline u64 kvm_pdptr_read_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, int index)
+{
+	load_pdptrs(vcpu, mmu, mmu->get_cr3(vcpu));
+
+	return mmu->pdptrs[index];
+}
+
 static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask)
 {
 	ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS;

arch/x86/kvm/mmu.c

@@ -2398,7 +2398,7 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
 
 		ASSERT(!VALID_PAGE(root));
 		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
-			pdptr = kvm_pdptr_read(vcpu, i);
+			pdptr = kvm_pdptr_read_mmu(vcpu, &vcpu->arch.mmu, i);
 			if (!is_present_gpte(pdptr)) {
 				vcpu->arch.mmu.pae_root[i] = 0;
 				continue;

arch/x86/kvm/paging_tmpl.h

@@ -137,7 +137,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
 
 #if PTTYPE == 64
 	if (walker->level == PT32E_ROOT_LEVEL) {
-		pte = kvm_pdptr_read(vcpu, (addr >> 30) & 3);
+		pte = kvm_pdptr_read_mmu(vcpu, mmu, (addr >> 30) & 3);
 		trace_kvm_mmu_paging_element(pte, walker->level);
 		if (!is_present_gpte(pte)) {
 			present = false;