[PATCH v2 18/21] KVM: arm64: Use common KVM implementation of MMU memory caches

From: Sean Christopherson
Date: Mon Jun 22 2020 - 16:10:02 EST

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.

Suggested-by: Christoffer Dall <christoffer.dall@xxxxxxx>
Tested-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/arm64/include/asm/Kbuild | 1 -
arch/arm64/include/asm/kvm_host.h | 12 -------
arch/arm64/include/asm/kvm_types.h | 8 +++++
arch/arm64/kvm/mmu.c | 51 ++++++------------------------
4 files changed, 18 insertions(+), 54 deletions(-)
create mode 100644 arch/arm64/include/asm/kvm_types.h

diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index 35a68155cd0e..ff9cbb631212 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -1,6 +1,5 @@
# 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
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 335170b59899..23d1f41548f5 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/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 */
diff --git a/arch/arm64/include/asm/kvm_types.h b/arch/arm64/include/asm/kvm_types.h
new file mode 100644
index 000000000000..9a126b9e2d7c
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_types.h
@@ -0,0 +1,8 @@
+/* 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 */
+
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 688213ef34f0..976405e2fbb2 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/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)
{
pud_t *pud_table __maybe_unused = stage2_pud_offset(kvm, pgd, 0UL);
@@ -1024,7 +993,7 @@ 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_memory_cache_alloc(cache);
stage2_pgd_populate(kvm, pgd, pud);
get_page(virt_to_page(pgd));
}
@@ -1045,7 +1014,7 @@ 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));
}
@@ -1251,7 +1220,7 @@ 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));
}
@@ -1276,7 +1245,7 @@ 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));
}
@@ -1343,7 +1312,7 @@ 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);
@@ -1354,8 +1323,8 @@ 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);
@@ -1369,7 +1338,7 @@ 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;
}

@@ -1735,7 +1704,7 @@ 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));
+ ret = kvm_mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm));
if (ret)
return ret;

@@ -2158,7 +2127,7 @@ 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)
--
2.26.0