[RFC PATCH 26/37] KVM: Move page table cache to struct kvm_vcpu

David Matlack
2022-12-08T19:40:25Z

Add a kvm_mmu_memory_cache to struct kvm_vcpu for allocating pages for
page tables, replacing existing architecture-specific page table caches.

Purposely do not make management of this cache architecture-neutral
though to reduce churn and since not all architectures configure it the
same way (MIPS does not set __GFP_ZERO.)

This eliminates a dependency of the TDP MMU on an architecture-specific
field, which will be used in a future commit to move the TDP MMU to
common code.

Signed-off-by: David Matlack <dmatlack@google.com>
---
arch/arm64/include/asm/kvm_host.h | 3 ---
arch/arm64/kvm/arm.c | 4 ++--
arch/arm64/kvm/mmu.c | 2 +-
arch/mips/include/asm/kvm_host.h | 3 ---
arch/mips/kvm/mmu.c | 4 ++--
arch/riscv/include/asm/kvm_host.h | 3 ---
arch/riscv/kvm/mmu.c | 2 +-
arch/riscv/kvm/vcpu.c | 4 ++--
arch/x86/include/asm/kvm_host.h | 1 -
arch/x86/kvm/mmu/mmu.c | 8 ++++----
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
include/linux/kvm_host.h | 5 +++++
12 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 001c8abe87fc..da519d6c09a5 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -473,9 +473,6 @@ struct kvm_vcpu_arch {
/* vcpu power state */
struct kvm_mp_state mp_state;

- /* Cache some mmu pages needed inside spinlock regions */
- struct kvm_mmu_memory_cache mmu_page_cache;
-
/* Target CPU and feature flags */
int target;
DECLARE_BITMAP(features, KVM_VCPU_MAX_FEATURES);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 9c5573bc4614..0e0d4c4f79a2 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -340,7 +340,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
vcpu->arch.target = -1;
bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);

- vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
+ vcpu->mmu_page_table_cache.gfp_zero = __GFP_ZERO;

/*
* Default value for the FP state, will be overloaded at load
@@ -375,7 +375,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
if (vcpu_has_run_once(vcpu) && unlikely(!irqchip_in_kernel(vcpu->kvm)))
static_branch_dec(&userspace_irqchip_in_use);

- kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+ kvm_mmu_free_memory_cache(&vcpu->mmu_page_table_cache);
kvm_timer_vcpu_terminate(vcpu);
kvm_pmu_vcpu_destroy(vcpu);

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 31d7fa4c7c14..d431c5cdb26a 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1196,7 +1196,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
bool device = false;
unsigned long mmu_seq;
struct kvm *kvm = vcpu->kvm;
- struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
+ struct kvm_mmu_memory_cache *memcache = &vcpu->mmu_page_table_cache;
struct vm_area_struct *vma;
short vma_shift;
gfn_t gfn;
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 5cedb28e8a40..b7f276331583 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -344,9 +344,6 @@ struct kvm_vcpu_arch {
/* Bitmask of pending exceptions to be cleared */
unsigned long pending_exceptions_clr;

- /* Cache some mmu pages needed inside spinlock regions */
- struct 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/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 74cd64a24d05..638f728d0bbe 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -27,7 +27,7 @@

void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
- kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+ kvm_mmu_free_memory_cache(&vcpu->mmu_page_table_cache);
}

/**
@@ -589,7 +589,7 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
pte_t *out_entry, pte_t *out_buddy)
{
struct kvm *kvm = vcpu->kvm;
- struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
+ struct kvm_mmu_memory_cache *memcache = &vcpu->mmu_page_table_cache;
gfn_t gfn = gpa >> PAGE_SHIFT;
int srcu_idx, err;
kvm_pfn_t pfn;
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index dbbf43d52623..82e5d80347cc 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -219,9 +219,6 @@ struct kvm_vcpu_arch {
/* SBI context */
struct kvm_sbi_context sbi_context;

- /* Cache pages needed to program page tables with spinlock held */
- struct kvm_mmu_memory_cache mmu_page_cache;
-
/* VCPU power-off state */
bool power_off;

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 3620ecac2fa1..a8281a65cb3d 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -625,7 +625,7 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
gfn_t gfn = gpa >> PAGE_SHIFT;
struct vm_area_struct *vma;
struct kvm *kvm = vcpu->kvm;
- struct kvm_mmu_memory_cache *pcache = &vcpu->arch.mmu_page_cache;
+ struct kvm_mmu_memory_cache *pcache = &vcpu->mmu_page_table_cache;
bool logging = (memslot->dirty_bitmap &&
!(memslot->flags & KVM_MEM_READONLY)) ? true : false;
unsigned long vma_pagesize, mmu_seq;
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 71ebbc4821f0..9a1001ada936 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -160,7 +160,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)

/* Mark this VCPU never ran */
vcpu->arch.ran_atleast_once = false;
- vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
+ vcpu->mmu_page_table_cache.gfp_zero = __GFP_ZERO;
bitmap_zero(vcpu->arch.isa, RISCV_ISA_EXT_MAX);

/* Setup ISA features available to VCPU */
@@ -211,7 +211,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
kvm_riscv_vcpu_timer_deinit(vcpu);

/* Free unused pages pre-allocated for G-stage page table mappings */
- kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+ kvm_mmu_free_memory_cache(&vcpu->mmu_page_table_cache);
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 95c731028452..8cac8ec29324 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -714,7 +714,6 @@ 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_info_cache;
struct kvm_mmu_memory_cache mmu_page_header_cache;

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index aea7df3c2dcb..a845e9141ad4 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -664,7 +664,7 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
1 + PT64_ROOT_MAX_LEVEL + PTE_PREFETCH_NUM);
if (r)
return r;
- r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_shadow_page_cache,
+ r = kvm_mmu_topup_memory_cache(&vcpu->mmu_page_table_cache,
PT64_ROOT_MAX_LEVEL);
if (r)
return r;
@@ -681,7 +681,7 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
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->arch.mmu_shadow_page_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);
}
@@ -2218,7 +2218,7 @@ static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu,
{
struct shadow_page_caches caches = {
.page_header_cache = &vcpu->arch.mmu_page_header_cache,
- .shadow_page_cache = &vcpu->arch.mmu_shadow_page_cache,
+ .shadow_page_cache = &vcpu->mmu_page_table_cache,
.shadowed_info_cache = &vcpu->arch.mmu_shadowed_info_cache,
};

@@ -5920,7 +5920,7 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;

- vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
+ vcpu->mmu_page_table_cache.gfp_zero = __GFP_ZERO;

vcpu->arch.mmu = &vcpu->arch.root_mmu;
vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index c5d1c9010d21..922815407b7e 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -264,7 +264,7 @@ 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->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache);
+ sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->mmu_page_table_cache);

return sp;
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 242eaed55320..0a9baa493760 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -387,6 +387,11 @@ struct kvm_vcpu {
*/
struct kvm_memory_slot *last_used_slot;
u64 last_used_slot_gen;
+
+#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;
+#endif
};

/*
--
2.39.0.rc1.256.g54fd8350bd-goog