Allow the capacity of the kvm_mmu_memory_cache struct to be chosen at
declaration time rather than being fixed for all declarations. This will
be used in a follow-up commit to declare an cache in x86 with a capacity
of 512+ objects without having to increase the capacity of all caches in
KVM.
No functional change intended.
Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 2 +-
arch/arm64/kvm/mmu.c | 12 ++++++------
arch/mips/include/asm/kvm_host.h | 2 +-
arch/x86/include/asm/kvm_host.h | 8 ++++----
include/linux/kvm_types.h | 24 ++++++++++++++++++++++--
virt/kvm/kvm_main.c | 8 +++++++-
6 files changed, 41 insertions(+), 15 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3b44ea17af88..a450b91cc2d9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -357,7 +357,7 @@ struct kvm_vcpu_arch {
bool pause;
/* Cache some mmu pages needed inside spinlock regions */
- struct kvm_mmu_memory_cache mmu_page_cache;
+ DEFINE_KVM_MMU_MEMORY_CACHE(mmu_page_cache);
/* Target CPU and feature flags */
int target;
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index bc2aba953299..9c853c529b49 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -765,7 +765,8 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
{
phys_addr_t addr;
int ret = 0;
- struct kvm_mmu_memory_cache cache = { 0, __GFP_ZERO, NULL, };
+ DEFINE_KVM_MMU_MEMORY_CACHE(cache) page_cache = {};
+ struct kvm_mmu_memory_cache *cache = &page_cache.cache;
struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
KVM_PGTABLE_PROT_R |
@@ -774,18 +775,17 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
if (is_protected_kvm_enabled())
return -EPERM;
+ cache->gfp_zero = __GFP_ZERO;
size += offset_in_page(guest_ipa);
guest_ipa &= PAGE_MASK;
for (addr = guest_ipa; addr < guest_ipa + size; addr += PAGE_SIZE) {
- ret = kvm_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)
break;
spin_lock(&kvm->mmu_lock);
- ret = kvm_pgtable_stage2_map(pgt, addr, PAGE_SIZE, pa, prot,
- &cache);
+ ret = kvm_pgtable_stage2_map(pgt, addr, PAGE_SIZE, pa, prot, cache);
spin_unlock(&kvm->mmu_lock);
if (ret)
break;
@@ -793,7 +793,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
pa += PAGE_SIZE;
}
- kvm_mmu_free_memory_cache(&cache);
+ kvm_mmu_free_memory_cache(cache);
return ret;
}
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 72b90d45a46e..82bbcbc3ead6 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -346,7 +346,7 @@ struct kvm_vcpu_arch {
unsigned long pending_exceptions_clr;
/* Cache some mmu pages needed inside spinlock regions */
- struct kvm_mmu_memory_cache mmu_page_cache;
+ DEFINE_KVM_MMU_MEMORY_CACHE(mmu_page_cache);
/* vcpu's vzguestid is different on each host cpu in an smp system */
u32 vzguestid[NR_CPUS];
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f00004c13ccf..d0b12bfe5818 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -684,10 +684,10 @@ struct kvm_vcpu_arch {
*/
struct kvm_mmu *walk_mmu;
- struct kvm_mmu_memory_cache mmu_pte_list_desc_cache;
- struct kvm_mmu_memory_cache mmu_shadow_page_cache;
- struct kvm_mmu_memory_cache mmu_shadowed_translation_cache;
- struct kvm_mmu_memory_cache mmu_page_header_cache;
+ DEFINE_KVM_MMU_MEMORY_CACHE(mmu_pte_list_desc_cache);
+ DEFINE_KVM_MMU_MEMORY_CACHE(mmu_shadow_page_cache);
+ DEFINE_KVM_MMU_MEMORY_CACHE(mmu_shadowed_translation_cache);
+ DEFINE_KVM_MMU_MEMORY_CACHE(mmu_page_header_cache);
/*
* QEMU userspace and the guest each have their own FPU state.
diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
index dceac12c1ce5..9575fb8d333f 100644
--- a/include/linux/kvm_types.h
+++ b/include/linux/kvm_types.h
@@ -78,14 +78,34 @@ struct gfn_to_pfn_cache {
* MMU flows is problematic, as is triggering reclaim, I/O, etc... while
* holding MMU locks. Note, these caches act more like prefetch buffers than
* classical caches, i.e. objects are not returned to the cache on being freed.
+ *
+ * The storage for the cache objects is laid out after the struct to allow
+ * different declarations to choose different capacities. If the capacity field
+ * is 0, the capacity is assumed to be KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE.
*/
struct kvm_mmu_memory_cache {
int nobjs;
+ int capacity;
gfp_t gfp_zero;
struct kmem_cache *kmem_cache;
- void *objects[KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE];
+ void *objects[0];
};
-#endif
+
+/*
+ * Note, if defining a memory cache with a non-default capacity, you must
+ * initialize the capacity field at runtime.
+ */
+#define __DEFINE_KVM_MMU_MEMORY_CACHE(_name, _capacity) \
+ struct { \
+ struct kvm_mmu_memory_cache _name; \
+ void *_name##_objects[_capacity]; \
+ }
+
+/* Define a memory cache with the default capacity. */
+#define DEFINE_KVM_MMU_MEMORY_CACHE(_name) \
+ __DEFINE_KVM_MMU_MEMORY_CACHE(_name, KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE)
+
+#endif /* KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE */
#define HALT_POLL_HIST_COUNT 32
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 034c567a680c..afa4bdb6481e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -373,11 +373,17 @@ static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
{
+ int capacity;
void *obj;
+ if (mc->capacity)
+ capacity = mc->capacity;
+ else
+ capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE;
+
if (mc->nobjs >= min)
return 0;
- while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
+ while (mc->nobjs < capacity) {
obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
if (!obj)
return mc->nobjs >= min ? 0 : -ENOMEM;
--
2.35.0.rc2.247.g8bbb082509-goog
