powerpc/kvm/book3s: Use kvm helpers to walk shadow or secondary table

update kvmppc_hv_handle_set_rc to use find_kvm_nested_guest_pte and
find_kvm_secondary_pte
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-12-aneesh.kumar@linux.ibm.com

arch/powerpc/include/asm/kvm_book3s.h

@@ -198,7 +198,7 @@ extern void kvmppc_unmap_pte(struct kvm *kvm, pte_t *pte, unsigned long gpa,
 			unsigned int shift,
 			const struct kvm_memory_slot *memslot,
 			unsigned int lpid);
-extern bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable,
+extern bool kvmppc_hv_handle_set_rc(struct kvm *kvm, bool nested,
 				    bool writing, unsigned long gpa,
 				    unsigned int lpid);
 extern int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,

arch/powerpc/include/asm/kvm_book3s_64.h

@@ -647,6 +647,9 @@ static inline pte_t *find_kvm_secondary_pte(struct kvm *kvm, unsigned long ea,
 	return pte;
 }
 
+extern pte_t *find_kvm_nested_guest_pte(struct kvm *kvm, unsigned long lpid,
+					unsigned long ea, unsigned *hshift);
+
 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
 
 #endif /* __ASM_KVM_BOOK3S_64_H__ */

arch/powerpc/kvm/book3s_64_mmu_radix.c

@@ -735,7 +735,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte,
 	return ret;
 }
 
-bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable, bool writing,
+bool kvmppc_hv_handle_set_rc(struct kvm *kvm, bool nested, bool writing,
 			     unsigned long gpa, unsigned int lpid)
 {
 	unsigned long pgflags;
@@ -750,12 +750,12 @@ bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable, bool writing,
 	pgflags = _PAGE_ACCESSED;
 	if (writing)
 		pgflags |= _PAGE_DIRTY;
-	/*
-	 * We are walking the secondary (partition-scoped) page table here.
-	 * We can do this without disabling irq because the Linux MM
-	 * subsystem doesn't do THP splits and collapses on this tree.
-	 */
-	ptep = __find_linux_pte(pgtable, gpa, NULL, &shift);
+
+	if (nested)
+		ptep = find_kvm_nested_guest_pte(kvm, lpid, gpa, &shift);
+	else
+		ptep = find_kvm_secondary_pte(kvm, gpa, &shift);
+
 	if (ptep && pte_present(*ptep) && (!writing || pte_write(*ptep))) {
 		kvmppc_radix_update_pte(kvm, ptep, 0, pgflags, gpa, shift);
 		return true;
@@ -949,8 +949,8 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	/* Failed to set the reference/change bits */
 	if (dsisr & DSISR_SET_RC) {
 		spin_lock(&kvm->mmu_lock);
-		if (kvmppc_hv_handle_set_rc(kvm, kvm->arch.pgtable,
-					    writing, gpa, kvm->arch.lpid))
+		if (kvmppc_hv_handle_set_rc(kvm, false, writing,
+					    gpa, kvm->arch.lpid))
 			dsisr &= ~DSISR_SET_RC;
 		spin_unlock(&kvm->mmu_lock);
 

arch/powerpc/kvm/book3s_hv_nested.c

@@ -750,8 +750,8 @@ static struct kvm_nested_guest *kvmhv_find_nested(struct kvm *kvm, int lpid)
 	return kvm->arch.nested_guests[lpid];
 }
 
-static pte_t *find_kvm_nested_guest_pte(struct kvm *kvm, unsigned long lpid,
-					unsigned long ea, unsigned *hshift)
+pte_t *find_kvm_nested_guest_pte(struct kvm *kvm, unsigned long lpid,
+				 unsigned long ea, unsigned *hshift)
 {
 	struct kvm_nested_guest *gp;
 	pte_t *pte;
@@ -767,7 +767,6 @@ static pte_t *find_kvm_nested_guest_pte(struct kvm *kvm, unsigned long lpid,
 	return pte;
 }
 
-
 static inline bool kvmhv_n_rmap_is_equal(u64 rmap_1, u64 rmap_2)
 {
 	return !((rmap_1 ^ rmap_2) & (RMAP_NESTED_LPID_MASK |
@@ -1226,16 +1225,16 @@ static long kvmhv_handle_nested_set_rc(struct kvm_vcpu *vcpu,
 
 	spin_lock(&kvm->mmu_lock);
 	/* Set the rc bit in the pte of our (L0) pgtable for the L1 guest */
-	ret = kvmppc_hv_handle_set_rc(kvm, kvm->arch.pgtable, writing,
-				     gpte.raddr, kvm->arch.lpid);
+	ret = kvmppc_hv_handle_set_rc(kvm, false, writing,
+				      gpte.raddr, kvm->arch.lpid);
 	if (!ret) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}
 
 	/* Set the rc bit in the pte of the shadow_pgtable for the nest guest */
-	ret = kvmppc_hv_handle_set_rc(kvm, gp->shadow_pgtable, writing, n_gpa,
-				      gp->shadow_lpid);
+	ret = kvmppc_hv_handle_set_rc(kvm, true, writing,
+				      n_gpa, gp->shadow_lpid);
 	if (!ret)
 		ret = -EINVAL;
 	else