KVM: arm64: Use common KVM implementation of MMU memory caches

Move to the common MMU memory cache implementation now that the common
code and arm64's existing code are semantically compatible.

No functional change intended.

Cc: Marc Zyngier <maz@kernel.org>
Suggested-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200703023545.8771-19-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/arm64/include/asm/Kbuild

 # SPDX-License-Identifier: GPL-2.0
 generic-y += early_ioremap.h
-generic-y += kvm_types.h
 generic-y += local64.h
 generic-y += mcs_spinlock.h
 generic-y += qrwlock.h

arch/arm64/include/asm/kvm_host.h

@@ -97,18 +97,6 @@ struct kvm_arch {
 	bool return_nisv_io_abort_to_user;
 };
 
-#define KVM_NR_MEM_OBJS     40
-
-/*
- * We don't want allocation failures within the mmu code, so we preallocate
- * enough memory for a single page fault in a cache.
- */
-struct kvm_mmu_memory_cache {
-	int nobjs;
-	gfp_t gfp_zero;
-	void *objects[KVM_NR_MEM_OBJS];
-};
-
 struct kvm_vcpu_fault_info {
 	u32 esr_el2;		/* Hyp Syndrom Register */
 	u64 far_el2;		/* Hyp Fault Address Register */

arch/arm64/include/asm/kvm_types.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARM64_KVM_TYPES_H
+#define _ASM_ARM64_KVM_TYPES_H
+
+#define KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE 40
+
+#endif /* _ASM_ARM64_KVM_TYPES_H */
+

arch/arm64/kvm/mmu.c

@@ -124,37 +124,6 @@ static void stage2_dissolve_pud(struct kvm *kvm, phys_addr_t addr, pud_t *pudp)
 	put_page(virt_to_page(pudp));
 }
 
-static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, int min)
-{
-	void *page;
-
-	if (cache->nobjs >= min)
-		return 0;
-	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
-		page = (void *)__get_free_page(GFP_KERNEL_ACCOUNT |
-					       cache->gfp_zero);
-		if (!page)
-			return -ENOMEM;
-		cache->objects[cache->nobjs++] = page;
-	}
-	return 0;
-}
-
-static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
-{
-	while (mc->nobjs)
-		free_page((unsigned long)mc->objects[--mc->nobjs]);
-}
-
-static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
-{
-	void *p;
-
-	BUG_ON(!mc || !mc->nobjs);
-	p = mc->objects[--mc->nobjs];
-	return p;
-}
-
 static void clear_stage2_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr)
 {
 	p4d_t *p4d_table __maybe_unused = stage2_p4d_offset(kvm, pgd, 0UL);
@@ -1131,7 +1100,7 @@ static p4d_t *stage2_get_p4d(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	if (stage2_pgd_none(kvm, *pgd)) {
 		if (!cache)
 			return NULL;
-		p4d = mmu_memory_cache_alloc(cache);
+		p4d = kvm_mmu_memory_cache_alloc(cache);
 		stage2_pgd_populate(kvm, pgd, p4d);
 		get_page(virt_to_page(pgd));
 	}
@@ -1149,7 +1118,7 @@ static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	if (stage2_p4d_none(kvm, *p4d)) {
 		if (!cache)
 			return NULL;
-		pud = mmu_memory_cache_alloc(cache);
+		pud = kvm_mmu_memory_cache_alloc(cache);
 		stage2_p4d_populate(kvm, p4d, pud);
 		get_page(virt_to_page(p4d));
 	}
@@ -1170,7 +1139,7 @@ static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	if (stage2_pud_none(kvm, *pud)) {
 		if (!cache)
 			return NULL;
-		pmd = mmu_memory_cache_alloc(cache);
+		pmd = kvm_mmu_memory_cache_alloc(cache);
 		stage2_pud_populate(kvm, pud, pmd);
 		get_page(virt_to_page(pud));
 	}
@@ -1376,7 +1345,7 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
 	if (stage2_pud_none(kvm, *pud)) {
 		if (!cache)
 			return 0; /* ignore calls from kvm_set_spte_hva */
-		pmd = mmu_memory_cache_alloc(cache);
+		pmd = kvm_mmu_memory_cache_alloc(cache);
 		stage2_pud_populate(kvm, pud, pmd);
 		get_page(virt_to_page(pud));
 	}
@@ -1401,7 +1370,7 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
 	if (pmd_none(*pmd)) {
 		if (!cache)
 			return 0; /* ignore calls from kvm_set_spte_hva */
-		pte = mmu_memory_cache_alloc(cache);
+		pte = kvm_mmu_memory_cache_alloc(cache);
 		kvm_pmd_populate(pmd, pte);
 		get_page(virt_to_page(pmd));
 	}
@@ -1468,7 +1437,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 	phys_addr_t addr, end;
 	int ret = 0;
 	unsigned long pfn;
-	struct kvm_mmu_memory_cache cache = { 0, __GFP_ZERO, };
+	struct kvm_mmu_memory_cache cache = { 0, __GFP_ZERO, NULL, };
 
 	end = (guest_ipa + size + PAGE_SIZE - 1) & PAGE_MASK;
 	pfn = __phys_to_pfn(pa);
@@ -1479,8 +1448,8 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 		if (writable)
 			pte = kvm_s2pte_mkwrite(pte);
 
-		ret = mmu_topup_memory_cache(&cache,
-					     kvm_mmu_cache_min_pages(kvm));
+		ret = kvm_mmu_topup_memory_cache(&cache,
+						 kvm_mmu_cache_min_pages(kvm));
 		if (ret)
 			goto out;
 		spin_lock(&kvm->mmu_lock);
@@ -1494,7 +1463,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 	}
 
 out:
-	mmu_free_memory_cache(&cache);
+	kvm_mmu_free_memory_cache(&cache);
 	return ret;
 }
 
@@ -1880,7 +1849,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	mmap_read_unlock(current->mm);
 
 	/* We need minimum second+third level pages */
-	ret = mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm));
+	ret = kvm_mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm));
 	if (ret)
 		return ret;
 
@@ -2303,7 +2272,7 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
 
 void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 {
-	mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
 }
 
 phys_addr_t kvm_mmu_get_httbr(void)