Patchwork [v2,3/4] KVM: arm/arm64: Move to common kvm_mmu_memcache infrastructure

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Submitter Christoffer Dall
Date Jan. 31, 2019, 9:52 a.m.
Message ID <20190131095244.7480-4-christoffer.dall@arm.com>
Download mbox | patch
Permalink /patch/714449/
State New
Headers show

Comments

Christoffer Dall - Jan. 31, 2019, 9:52 a.m.
Now when we have a common mmu mmemcache implementation, we can reuse
this for arm and arm64.

The common implementation has a slightly different behavior when
allocating objects under high memory pressure; whereas the current
arm/arm64 implementation will give up and return -ENOMEM if the full
size of the cache cannot be allocated during topup, the common
implementation is happy with any allocation between min and max.  There
should be no architecture-specific requirement for doing it one way or
the other and it's in fact better to enforce a cross-architecture KVM
policy on this behavior.

Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
---
 arch/arm/include/asm/kvm_host.h    | 13 +-----
 arch/arm/include/asm/kvm_mmu.h     |  2 +-
 arch/arm/include/asm/kvm_types.h   |  7 +++
 arch/arm64/include/asm/kvm_host.h  | 13 +-----
 arch/arm64/include/asm/kvm_mmu.h   |  2 +-
 arch/arm64/include/asm/kvm_types.h |  7 +++
 virt/kvm/arm/arm.c                 |  2 +-
 virt/kvm/arm/mmu.c                 | 68 ++++++++----------------------
 8 files changed, 36 insertions(+), 78 deletions(-)

Patch

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index ca56537b61bc..bf6b6d027ff0 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -83,17 +83,6 @@  struct kvm_arch {
 	u32 psci_version;
 };
 
-#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;
-	void *objects[KVM_NR_MEM_OBJS];
-};
-
 struct kvm_vcpu_fault_info {
 	u32 hsr;		/* Hyp Syndrome Register */
 	u32 hxfar;		/* Hyp Data/Inst. Fault Address Register */
@@ -184,7 +173,7 @@  struct kvm_vcpu_arch {
 	struct kvm_decode mmio_decode;
 
 	/* Cache some mmu pages needed inside spinlock regions */
-	struct kvm_mmu_memory_cache mmu_page_cache;
+	struct kvm_mmu_memcache mmu_page_cache;
 
 	/* Detect first run of a vcpu */
 	bool has_run_once;
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 3a875fc1b63c..8877f53997c8 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -71,7 +71,7 @@  int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 
 int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
 
-void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
+void kvm_mmu_free_memcaches(struct kvm_vcpu *vcpu);
 
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
diff --git a/arch/arm/include/asm/kvm_types.h b/arch/arm/include/asm/kvm_types.h
index bc389f82e88d..51c9b0cb9718 100644
--- a/arch/arm/include/asm/kvm_types.h
+++ b/arch/arm/include/asm/kvm_types.h
@@ -2,4 +2,11 @@ 
 #ifndef _ASM_ARM_KVM_TYPES_H
 #define _ASM_ARM_KVM_TYPES_H
 
+#define KVM_ARCH_WANT_MMU_MEMCACHE
+
+#define KVM_MMU_NR_MEMCACHE_OBJS 40
+
+#define KVM_MMU_CACHE_GFP	GFP_KERNEL
+#define KVM_MMU_CACHE_PAGE_GFP	(GFP_KERNEL | __GFP_ZERO)
+
 #endif /* _ASM_ARM_KVM_TYPES_H */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7732d0ba4e60..1aa951de8338 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -82,17 +82,6 @@  struct kvm_arch {
 	u32 psci_version;
 };
 
-#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;
-	void *objects[KVM_NR_MEM_OBJS];
-};
-
 struct kvm_vcpu_fault_info {
 	u32 esr_el2;		/* Hyp Syndrom Register */
 	u64 far_el2;		/* Hyp Fault Address Register */
@@ -285,7 +274,7 @@  struct kvm_vcpu_arch {
 	struct kvm_decode mmio_decode;
 
 	/* Cache some mmu pages needed inside spinlock regions */
-	struct kvm_mmu_memory_cache mmu_page_cache;
+	struct kvm_mmu_memcache mmu_page_cache;
 
 	/* Target CPU and feature flags */
 	int target;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 8af4b1befa42..dec55fa00e56 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -170,7 +170,7 @@  int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 
 int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
 
-void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
+void kvm_mmu_free_memcaches(struct kvm_vcpu *vcpu);
 
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
diff --git a/arch/arm64/include/asm/kvm_types.h b/arch/arm64/include/asm/kvm_types.h
index d0987007d581..706f6cb6f9f3 100644
--- a/arch/arm64/include/asm/kvm_types.h
+++ b/arch/arm64/include/asm/kvm_types.h
@@ -2,5 +2,12 @@ 
 #ifndef _ASM_ARM64_KVM_TYPES_H
 #define _ASM_ARM64_KVM_TYPES_H
 
+#define KVM_ARCH_WANT_MMU_MEMCACHE
+
+#define KVM_MMU_NR_MEMCACHE_OBJS 40
+
+#define KVM_MMU_CACHE_GFP	GFP_KERNEL
+#define KVM_MMU_CACHE_PAGE_GFP	(GFP_KERNEL | __GFP_ZERO)
+
 #endif /* _ASM_ARM64_KVM_TYPES_H */
 
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 9e350fd34504..89c89a151373 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -317,7 +317,7 @@  void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.has_run_once && unlikely(!irqchip_in_kernel(vcpu->kvm)))
 		static_branch_dec(&userspace_irqchip_in_use);
 
-	kvm_mmu_free_memory_caches(vcpu);
+	kvm_mmu_free_memcaches(vcpu);
 	kvm_timer_vcpu_terminate(vcpu);
 	kvm_pmu_vcpu_destroy(vcpu);
 	kvm_vcpu_uninit(vcpu);
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index fbdf3ac2f001..da193b446261 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -134,38 +134,6 @@  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, int max)
-{
-	void *page;
-
-	BUG_ON(max > KVM_NR_MEM_OBJS);
-	if (cache->nobjs >= min)
-		return 0;
-	while (cache->nobjs < max) {
-		page = (void *)__get_free_page(PGALLOC_GFP);
-		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)
 {
 	pud_t *pud_table __maybe_unused = stage2_pud_offset(kvm, pgd, 0UL);
@@ -1016,7 +984,7 @@  void kvm_free_stage2_pgd(struct kvm *kvm)
 		free_pages_exact(pgd, stage2_pgd_size(kvm));
 }
 
-static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
+static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memcache *cache,
 			     phys_addr_t addr)
 {
 	pgd_t *pgd;
@@ -1026,7 +994,7 @@  static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	if (stage2_pgd_none(kvm, *pgd)) {
 		if (!cache)
 			return NULL;
-		pud = mmu_memory_cache_alloc(cache);
+		pud = kvm_mmu_memcache_alloc(cache);
 		stage2_pgd_populate(kvm, pgd, pud);
 		get_page(virt_to_page(pgd));
 	}
@@ -1034,7 +1002,7 @@  static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	return stage2_pud_offset(kvm, pgd, addr);
 }
 
-static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
+static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memcache *cache,
 			     phys_addr_t addr)
 {
 	pud_t *pud;
@@ -1047,7 +1015,7 @@  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_memcache_alloc(cache);
 		stage2_pud_populate(kvm, pud, pmd);
 		get_page(virt_to_page(pud));
 	}
@@ -1055,7 +1023,7 @@  static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	return stage2_pmd_offset(kvm, pud, addr);
 }
 
-static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache
+static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memcache
 			       *cache, phys_addr_t addr, const pmd_t *new_pmd)
 {
 	pmd_t *pmd, old_pmd;
@@ -1102,7 +1070,7 @@  static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache
 	return 0;
 }
 
-static int stage2_set_pud_huge(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
+static int stage2_set_pud_huge(struct kvm *kvm, struct kvm_mmu_memcache *cache,
 			       phys_addr_t addr, const pud_t *new_pudp)
 {
 	pud_t *pudp, old_pud;
@@ -1194,7 +1162,7 @@  static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr)
 		return kvm_s2pte_exec(ptep);
 }
 
-static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
+static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memcache *cache,
 			  phys_addr_t addr, const pte_t *new_pte,
 			  unsigned long flags)
 {
@@ -1226,7 +1194,7 @@  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_memcache_alloc(cache);
 		stage2_pud_populate(kvm, pud, pmd);
 		get_page(virt_to_page(pud));
 	}
@@ -1251,7 +1219,7 @@  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_memcache_alloc(cache);
 		kvm_pmd_populate(pmd, pte);
 		get_page(virt_to_page(pmd));
 	}
@@ -1318,7 +1286,7 @@  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, };
+	struct kvm_mmu_memcache cache = { 0, };
 
 	end = (guest_ipa + size + PAGE_SIZE - 1) & PAGE_MASK;
 	pfn = __phys_to_pfn(pa);
@@ -1329,9 +1297,8 @@  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),
-					     KVM_NR_MEM_OBJS);
+		ret = kvm_mmu_topup_memcache_page(&cache,
+						  kvm_mmu_cache_min_pages(kvm));
 		if (ret)
 			goto out;
 		spin_lock(&kvm->mmu_lock);
@@ -1345,7 +1312,7 @@  int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 	}
 
 out:
-	mmu_free_memory_cache(&cache);
+	kvm_mmu_free_memcache_page(&cache);
 	return ret;
 }
 
@@ -1662,7 +1629,7 @@  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	unsigned long mmu_seq;
 	gfn_t gfn = fault_ipa >> PAGE_SHIFT;
 	struct kvm *kvm = vcpu->kvm;
-	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
+	struct kvm_mmu_memcache *memcache = &vcpu->arch.mmu_page_cache;
 	struct vm_area_struct *vma;
 	kvm_pfn_t pfn;
 	pgprot_t mem_type = PAGE_S2;
@@ -1706,8 +1673,7 @@  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	up_read(&current->mm->mmap_sem);
 
 	/* We need minimum second+third level pages */
-	ret = mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm),
-				     KVM_NR_MEM_OBJS);
+	ret = kvm_mmu_topup_memcache_page(memcache, kvm_mmu_cache_min_pages(kvm));
 	if (ret)
 		return ret;
 
@@ -2123,9 +2089,9 @@  int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
 	return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
 }
 
-void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
+void kvm_mmu_free_memcaches(struct kvm_vcpu *vcpu)
 {
-	mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+	kvm_mmu_free_memcache_page(&vcpu->arch.mmu_page_cache);
 }
 
 phys_addr_t kvm_mmu_get_httbr(void)