KVM: PPC: Use kvm_faultin_pfn() to handle page faults on Book3s PR

Convert Book3S PR to __kvm_faultin_pfn()+kvm_release_faultin_page(), which
are new APIs to consolidate arch code and provide consistent behavior
across all KVM architectures.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-65-seanjc@google.com>

Author: sean-jc

arch/powerpc/include/asm/kvm_book3s.h

@@ -235,7 +235,7 @@ extern void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat,
 extern void kvmppc_giveup_ext(struct kvm_vcpu *vcpu, ulong msr);
 extern int kvmppc_emulate_paired_single(struct kvm_vcpu *vcpu);
 extern kvm_pfn_t kvmppc_gpa_to_pfn(struct kvm_vcpu *vcpu, gpa_t gpa,
-			bool writing, bool *writable);
+			bool writing, bool *writable, struct page **page);
 extern void kvmppc_add_revmap_chain(struct kvm *kvm, struct revmap_entry *rev,
 			unsigned long *rmap, long pte_index, int realmode);
 extern void kvmppc_update_dirty_map(const struct kvm_memory_slot *memslot,

arch/powerpc/kvm/book3s.c

@@ -422,7 +422,7 @@ int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu)
 EXPORT_SYMBOL_GPL(kvmppc_core_prepare_to_enter);
 
 kvm_pfn_t kvmppc_gpa_to_pfn(struct kvm_vcpu *vcpu, gpa_t gpa, bool writing,
-			bool *writable)
+			    bool *writable, struct page **page)
 {
 	ulong mp_pa = vcpu->arch.magic_page_pa & KVM_PAM;
 	gfn_t gfn = gpa >> PAGE_SHIFT;
@@ -437,13 +437,14 @@ kvm_pfn_t kvmppc_gpa_to_pfn(struct kvm_vcpu *vcpu, gpa_t gpa, bool writing,
 		kvm_pfn_t pfn;
 
 		pfn = (kvm_pfn_t)virt_to_phys((void*)shared_page) >> PAGE_SHIFT;
-		get_page(pfn_to_page(pfn));
+		*page = pfn_to_page(pfn);
+		get_page(*page);
 		if (writable)
 			*writable = true;
 		return pfn;
 	}
 
-	return gfn_to_pfn_prot(vcpu->kvm, gfn, writing, writable);
+	return kvm_faultin_pfn(vcpu, gfn, writing, writable, page);
 }
 EXPORT_SYMBOL_GPL(kvmppc_gpa_to_pfn);
 

arch/powerpc/kvm/book3s_32_mmu_host.c

@@ -130,6 +130,7 @@ extern char etext[];
 int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 			bool iswrite)
 {
+	struct page *page;
 	kvm_pfn_t hpaddr;
 	u64 vpn;
 	u64 vsid;
@@ -145,7 +146,7 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 	bool writable;
 
 	/* Get host physical address for gpa */
-	hpaddr = kvmppc_gpa_to_pfn(vcpu, orig_pte->raddr, iswrite, &writable);
+	hpaddr = kvmppc_gpa_to_pfn(vcpu, orig_pte->raddr, iswrite, &writable, &page);
 	if (is_error_noslot_pfn(hpaddr)) {
 		printk(KERN_INFO "Couldn't get guest page for gpa %lx!\n",
 				 orig_pte->raddr);
@@ -232,7 +233,7 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 
 	pte = kvmppc_mmu_hpte_cache_next(vcpu);
 	if (!pte) {
-		kvm_release_pfn_clean(hpaddr >> PAGE_SHIFT);
+		kvm_release_page_unused(page);
 		r = -EAGAIN;
 		goto out;
 	}
@@ -250,7 +251,7 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 
 	kvmppc_mmu_hpte_cache_map(vcpu, pte);
 
-	kvm_release_pfn_clean(hpaddr >> PAGE_SHIFT);
+	kvm_release_page_clean(page);
 out:
 	return r;
 }

arch/powerpc/kvm/book3s_64_mmu_host.c

@@ -88,13 +88,14 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 	struct hpte_cache *cpte;
 	unsigned long gfn = orig_pte->raddr >> PAGE_SHIFT;
 	unsigned long pfn;
+	struct page *page;
 
 	/* used to check for invalidations in progress */
 	mmu_seq = kvm->mmu_invalidate_seq;
 	smp_rmb();
 
 	/* Get host physical address for gpa */
-	pfn = kvmppc_gpa_to_pfn(vcpu, orig_pte->raddr, iswrite, &writable);
+	pfn = kvmppc_gpa_to_pfn(vcpu, orig_pte->raddr, iswrite, &writable, &page);
 	if (is_error_noslot_pfn(pfn)) {
 		printk(KERN_INFO "Couldn't get guest page for gpa %lx!\n",
 		       orig_pte->raddr);
@@ -199,10 +200,9 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 	}
 
 out_unlock:
-	if (!orig_pte->may_write || !writable)
-		kvm_release_pfn_clean(pfn);
-	else
-		kvm_release_pfn_dirty(pfn);
+	/* FIXME: Don't unconditionally pass unused=false. */
+	kvm_release_faultin_page(kvm, page, false,
+				 orig_pte->may_write && writable);
 	spin_unlock(&kvm->mmu_lock);
 	if (cpte)
 		kvmppc_mmu_hpte_cache_free(cpte);