[RFC PATCH 27/37] KVM: MMU: Move mmu_page_header_cache to common code

David Matlack
2022-12-08T20:31:12Z

Move vcpu->arch.mmu_page_header_cache and its backing kmem_cache to common code
in preparation for moving the TDP MMU to common code in a future commit.

The kmem_cache is still only initialized and used on x86 for the time being to
avoid affecting other architectures. A future commit can move the code to
manage this cache to common code.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
---
arch/x86/kvm/mmu/mmu.c | 11 +++++------
arch/x86/kvm/mmu/mmu_internal.h | 2 --
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
include/kvm/mmu.h | 2 ++
include/linux/kvm_host.h | 3 +++
virt/kvm/kvm_main.c | 1 +
6 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a845e9141ad4..f01ee01f3509 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -163,7 +163,6 @@ struct kvm_shadow_walk_iterator {
__shadow_walk_next(&(_walker), spte))

static struct kmem_cache *pte_list_desc_cache;
-struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;

static void mmu_spte_set(u64 *sptep, u64 spte);
@@ -674,7 +673,7 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
if (r)
return r;
}
- return kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
+ return kvm_mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
PT64_ROOT_MAX_LEVEL);
}

@@ -683,7 +682,7 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
kvm_mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache);
kvm_mmu_free_memory_cache(&vcpu->mmu_page_table_cache);
kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadowed_info_cache);
- kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
+ kvm_mmu_free_memory_cache(&vcpu->mmu_page_header_cache);
}

static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
@@ -2217,7 +2216,7 @@ static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu,
union kvm_mmu_page_role role)
{
struct shadow_page_caches caches = {
- .page_header_cache = &vcpu->arch.mmu_page_header_cache,
+ .page_header_cache = &vcpu->mmu_page_header_cache,
.shadow_page_cache = &vcpu->mmu_page_table_cache,
.shadowed_info_cache = &vcpu->arch.mmu_shadowed_info_cache,
};
@@ -5917,8 +5916,8 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;

- vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
- vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
+ vcpu->mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
+ vcpu->mmu_page_header_cache.gfp_zero = __GFP_ZERO;

vcpu->mmu_page_table_cache.gfp_zero = __GFP_ZERO;

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index d3c1d08002af..4aa60d5d87b0 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -44,8 +44,6 @@ extern bool dbg;
#define INVALID_PAE_ROOT 0
#define IS_VALID_PAE_ROOT(x) (!!(x))

-extern struct kmem_cache *mmu_page_header_cache;
-
static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp)
{
/*
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 922815407b7e..891877a6fb78 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -263,7 +263,7 @@ static struct kvm_mmu_page *tdp_mmu_alloc_sp(struct kvm_vcpu *vcpu)
{
struct kvm_mmu_page *sp;

- sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
+ sp = kvm_mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache);
sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->mmu_page_table_cache);

return sp;
diff --git a/include/kvm/mmu.h b/include/kvm/mmu.h
index 425db8e4f8e9..f1416828f8fe 100644
--- a/include/kvm/mmu.h
+++ b/include/kvm/mmu.h
@@ -4,6 +4,8 @@

#include <kvm/mmu_types.h>

+extern struct kmem_cache *mmu_page_header_cache;
+
static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page)
{
struct page *page = pfn_to_page((shadow_page) >> PAGE_SHIFT);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0a9baa493760..ec3a6de6d54e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -391,6 +391,9 @@ struct kvm_vcpu {
#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
/* Cache used to allocate pages for use as page tables. */
struct kvm_mmu_memory_cache mmu_page_table_cache;
+
+ /* Cache used to allocate kvm_mmu_page structs. */
+ struct kvm_mmu_memory_cache mmu_page_header_cache;
#endif
};

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 954ab969f55e..0f1d48ed7d57 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -108,6 +108,7 @@ static int kvm_usage_count;
static atomic_t hardware_enable_failed;

static struct kmem_cache *kvm_vcpu_cache;
+struct kmem_cache *mmu_page_header_cache;

static __read_mostly struct preempt_ops kvm_preempt_ops;
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
--
2.39.0.rc1.256.g54fd8350bd-goog