Patchwork [1/3] KVM: x86: Move mmu_memory_cache functions to common code

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Submitter Christoffer Dall
Date Jan. 28, 2019, 2:48 p.m.
Message ID <20190128144843.11635-2-christoffer.dall@arm.com>
Download mbox | patch
Permalink /patch/711043/
State New
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Comments

Christoffer Dall - Jan. 28, 2019, 2:48 p.m.
We are currently duplicating the mmu memory cache functionality quite
heavily between the architectures that support KVM.  As a first step,
move the x86 implementation (which seems to have the most recently
maintained version of the mmu memory cache) to common code.

We rename the functions and data types to have a kvm_ prefix for
anything exported as a symbol to the rest of the kernel and take the
chance to rename memory_cache to memcache to avoid overly long lines.
This is a bit tedious on the callsites but ends up looking more
palatable.

We also introduce an arch-specific kvm_types.h which can be used to
define the architecture-specific GFP flags for allocating memory to the
memory cache, and to specify how many objects are required in the memory
cache.  These are the two points where the current implementations
diverge across architectures.  Since kvm_host.h defines structures with
fields of the memcache object, we define the memcache structure in
kvm_types.h, and we include the architecture-specific kvm_types.h to
know the size of object in kvm_host.h.

This patch currently only defines the structure and requires valid
defines in the architecture-specific kvm_types.h when KVM_NR_MEM_OBJS is
defined.  As we move each architecture to the common implementation,
this condition will eventually go away.

Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
---
 arch/arm/include/asm/kvm_types.h     |  5 ++
 arch/arm64/include/asm/kvm_types.h   |  6 ++
 arch/mips/include/asm/kvm_types.h    |  5 ++
 arch/powerpc/include/asm/kvm_types.h |  5 ++
 arch/s390/include/asm/kvm_types.h    |  5 ++
 arch/x86/include/asm/kvm_host.h      | 17 +----
 arch/x86/include/asm/kvm_types.h     | 10 +++
 arch/x86/kvm/mmu.c                   | 97 ++++++----------------------
 arch/x86/kvm/paging_tmpl.h           |  4 +-
 include/linux/kvm_host.h             |  9 +++
 include/linux/kvm_types.h            | 12 ++++
 virt/kvm/kvm_main.c                  | 58 +++++++++++++++++
 12 files changed, 139 insertions(+), 94 deletions(-)
 create mode 100644 arch/arm/include/asm/kvm_types.h
 create mode 100644 arch/arm64/include/asm/kvm_types.h
 create mode 100644 arch/mips/include/asm/kvm_types.h
 create mode 100644 arch/powerpc/include/asm/kvm_types.h
 create mode 100644 arch/s390/include/asm/kvm_types.h
 create mode 100644 arch/x86/include/asm/kvm_types.h
Christopherson, Sean J - Jan. 28, 2019, 4:19 p.m.
On Mon, Jan 28, 2019 at 03:48:41PM +0100, Christoffer Dall wrote:
> We are currently duplicating the mmu memory cache functionality quite
> heavily between the architectures that support KVM.  As a first step,
> move the x86 implementation (which seems to have the most recently
> maintained version of the mmu memory cache) to common code.
> 
> We rename the functions and data types to have a kvm_ prefix for
> anything exported as a symbol to the rest of the kernel and take the
> chance to rename memory_cache to memcache to avoid overly long lines.

It'd be helpful to do the rename it a separate patch so that the move
really is a straight move of code.

> This is a bit tedious on the callsites but ends up looking more
> palatable.
> 
> We also introduce an arch-specific kvm_types.h which can be used to
> define the architecture-specific GFP flags for allocating memory to the
> memory cache, and to specify how many objects are required in the memory
> cache.  These are the two points where the current implementations
> diverge across architectures.  Since kvm_host.h defines structures with
> fields of the memcache object, we define the memcache structure in
> kvm_types.h, and we include the architecture-specific kvm_types.h to
> know the size of object in kvm_host.h.
> 
> This patch currently only defines the structure and requires valid
> defines in the architecture-specific kvm_types.h when KVM_NR_MEM_OBJS is
> defined.  As we move each architecture to the common implementation,
> this condition will eventually go away.
> 
> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
> ---
>  arch/arm/include/asm/kvm_types.h     |  5 ++
>  arch/arm64/include/asm/kvm_types.h   |  6 ++
>  arch/mips/include/asm/kvm_types.h    |  5 ++
>  arch/powerpc/include/asm/kvm_types.h |  5 ++
>  arch/s390/include/asm/kvm_types.h    |  5 ++
>  arch/x86/include/asm/kvm_host.h      | 17 +----
>  arch/x86/include/asm/kvm_types.h     | 10 +++
>  arch/x86/kvm/mmu.c                   | 97 ++++++----------------------
>  arch/x86/kvm/paging_tmpl.h           |  4 +-
>  include/linux/kvm_host.h             |  9 +++
>  include/linux/kvm_types.h            | 12 ++++
>  virt/kvm/kvm_main.c                  | 58 +++++++++++++++++
>  12 files changed, 139 insertions(+), 94 deletions(-)
>  create mode 100644 arch/arm/include/asm/kvm_types.h
>  create mode 100644 arch/arm64/include/asm/kvm_types.h
>  create mode 100644 arch/mips/include/asm/kvm_types.h
>  create mode 100644 arch/powerpc/include/asm/kvm_types.h
>  create mode 100644 arch/s390/include/asm/kvm_types.h
>  create mode 100644 arch/x86/include/asm/kvm_types.h
> 
> diff --git a/arch/arm/include/asm/kvm_types.h b/arch/arm/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..bc389f82e88d
> --- /dev/null
> +++ b/arch/arm/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_ARM_KVM_TYPES_H
> +#define _ASM_ARM_KVM_TYPES_H
> +
> +#endif /* _ASM_ARM_KVM_TYPES_H */
> diff --git a/arch/arm64/include/asm/kvm_types.h b/arch/arm64/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..d0987007d581
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_types.h
> @@ -0,0 +1,6 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_ARM64_KVM_TYPES_H
> +#define _ASM_ARM64_KVM_TYPES_H
> +
> +#endif /* _ASM_ARM64_KVM_TYPES_H */
> +
> diff --git a/arch/mips/include/asm/kvm_types.h b/arch/mips/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..5efeb32a5926
> --- /dev/null
> +++ b/arch/mips/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_MIPS_KVM_TYPES_H
> +#define _ASM_MIPS_KVM_TYPES_H
> +
> +#endif /* _ASM_MIPS_KVM_TYPES_H */
> diff --git a/arch/powerpc/include/asm/kvm_types.h b/arch/powerpc/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..f627eceaa314
> --- /dev/null
> +++ b/arch/powerpc/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_POWERPC_KVM_TYPES_H
> +#define _ASM_POWERPC_KVM_TYPES_H
> +
> +#endif /* _ASM_POWERPC_KVM_TYPES_H */
> diff --git a/arch/s390/include/asm/kvm_types.h b/arch/s390/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..b66a81f8a354
> --- /dev/null
> +++ b/arch/s390/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_S390_KVM_TYPES_H
> +#define _ASM_S390_KVM_TYPES_H
> +
> +#endif /* _ASM_S390_KVM_TYPES_H */
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 4660ce90de7f..5c12cba8c2b1 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -179,8 +179,6 @@ enum {
>  
>  #include <asm/kvm_emulate.h>
>  
> -#define KVM_NR_MEM_OBJS 40
> -
>  #define KVM_NR_DB_REGS	4
>  
>  #define DR6_BD		(1 << 13)
> @@ -238,15 +236,6 @@ enum {
>  
>  struct kvm_kernel_irq_routing_entry;
>  
> -/*
> - * 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];
> -};
> -
>  /*
>   * the pages used as guest page table on soft mmu are tracked by
>   * kvm_memory_slot.arch.gfn_track which is 16 bits, so the role bits used
> @@ -600,9 +589,9 @@ 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_page_cache;
> -	struct kvm_mmu_memory_cache mmu_page_header_cache;
> +	struct kvm_mmu_memcache mmu_pte_list_desc_cache;
> +	struct kvm_mmu_memcache mmu_page_cache;
> +	struct kvm_mmu_memcache mmu_page_header_cache;
>  
>  	/*
>  	 * QEMU userspace and the guest each have their own FPU state.
> diff --git a/arch/x86/include/asm/kvm_types.h b/arch/x86/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..f71fe5556b6f
> --- /dev/null
> +++ b/arch/x86/include/asm/kvm_types.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_KVM_TYPES_H
> +#define _ASM_X86_KVM_TYPES_H
> +
> +#define KVM_NR_MEM_OBJS 40
> +
> +#define KVM_MMU_CACHE_GFP	GFP_KERNEL
> +#define KVM_MMU_CACHE_PAGE_GFP	GFP_KERNEL_ACCOUNT
> +
> +#endif /* _ASM_X86_KVM_TYPES_H */
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index ce770b446238..cf0024849404 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -951,94 +951,35 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
>  	local_irq_enable();
>  }
>  
> -static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
> -				  struct kmem_cache *base_cache, int min)
> -{
> -	void *obj;
> -
> -	if (cache->nobjs >= min)
> -		return 0;
> -	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> -		obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
> -		if (!obj)
> -			return cache->nobjs >= min ? 0 : -ENOMEM;
> -		cache->objects[cache->nobjs++] = obj;
> -	}
> -	return 0;
> -}
> -
> -static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
> -{
> -	return cache->nobjs;
> -}
> -
> -static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
> -				  struct kmem_cache *cache)
> -{
> -	while (mc->nobjs)
> -		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
> -}
> -
> -static int mmu_topup_memory_cache_page(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);
> -		if (!page)
> -			return cache->nobjs >= min ? 0 : -ENOMEM;
> -		cache->objects[cache->nobjs++] = page;
> -	}
> -	return 0;
> -}
> -
> -static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
> -{
> -	while (mc->nobjs)
> -		free_page((unsigned long)mc->objects[--mc->nobjs]);
> -}
> -
> -static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
> +static int mmu_topup_memcaches(struct kvm_vcpu *vcpu)
>  {
>  	int r;
>  
> -	r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
> +	r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
>  				   pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
>  	if (r)
>  		goto out;
> -	r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
> +	r = kvm_mmu_topup_memcache_page(&vcpu->arch.mmu_page_cache, 8);
>  	if (r)
>  		goto out;
> -	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
> +	r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_page_header_cache,
>  				   mmu_page_header_cache, 4);
>  out:
>  	return r;
>  }
>  
> -static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
> +static void mmu_free_memcaches(struct kvm_vcpu *vcpu)
>  {
> -	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
> +	kvm_mmu_free_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
>  				pte_list_desc_cache);
> -	mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
> -	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
> +	kvm_mmu_free_memcache_page(&vcpu->arch.mmu_page_cache);
> +	kvm_mmu_free_memcache(&vcpu->arch.mmu_page_header_cache,
>  				mmu_page_header_cache);
>  }
>  
> -static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
> -{
> -	void *p;
> -
> -	BUG_ON(!mc->nobjs);
> -	p = mc->objects[--mc->nobjs];
> -	return p;
> -}
> -
>  static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
>  {
> -	return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
> +	return kvm_mmu_memcache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
>  }
>  
>  static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
> @@ -1358,10 +1299,10 @@ static struct kvm_rmap_head *gfn_to_rmap(struct kvm *kvm, gfn_t gfn,
>  
>  static bool rmap_can_add(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm_mmu_memory_cache *cache;
> +	struct kvm_mmu_memcache *cache;
>  
>  	cache = &vcpu->arch.mmu_pte_list_desc_cache;
> -	return mmu_memory_cache_free_objects(cache);
> +	return kvm_mmu_memcache_free_objects(cache);
>  }
>  
>  static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
> @@ -2044,10 +1985,10 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
>  {
>  	struct kvm_mmu_page *sp;
>  
> -	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
> -	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> +	sp = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_header_cache);
> +	sp->spt = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
>  	if (!direct)
> -		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> +		sp->gfns = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
>  	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
>  
>  	/*
> @@ -3961,7 +3902,7 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
>  	if (page_fault_handle_page_track(vcpu, error_code, gfn))
>  		return RET_PF_EMULATE;
>  
> -	r = mmu_topup_memory_caches(vcpu);
> +	r = mmu_topup_memcaches(vcpu);
>  	if (r)
>  		return r;
>  
> @@ -4090,7 +4031,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
>  	if (page_fault_handle_page_track(vcpu, error_code, gfn))
>  		return RET_PF_EMULATE;
>  
> -	r = mmu_topup_memory_caches(vcpu);
> +	r = mmu_topup_memcaches(vcpu);
>  	if (r)
>  		return r;
>  
> @@ -5062,7 +5003,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
>  {
>  	int r;
>  
> -	r = mmu_topup_memory_caches(vcpu);
> +	r = mmu_topup_memcaches(vcpu);
>  	if (r)
>  		goto out;
>  	r = mmu_alloc_roots(vcpu);
> @@ -5240,7 +5181,7 @@ static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
>  	 * or not since pte prefetch is skiped if it does not have
>  	 * enough objects in the cache.
>  	 */
> -	mmu_topup_memory_caches(vcpu);
> +	mmu_topup_memcaches(vcpu);
>  
>  	spin_lock(&vcpu->kvm->mmu_lock);
>  
> @@ -6052,7 +5993,7 @@ void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
>  {
>  	kvm_mmu_unload(vcpu);
>  	free_mmu_pages(vcpu);
> -	mmu_free_memory_caches(vcpu);
> +	mmu_free_memcaches(vcpu);
>  }
>  
>  void kvm_mmu_module_exit(void)
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 6bdca39829bc..c32b603639a9 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -747,7 +747,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
>  
>  	pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
>  
> -	r = mmu_topup_memory_caches(vcpu);
> +	r = mmu_topup_memcaches(vcpu);
>  	if (r)
>  		return r;
>  
> @@ -870,7 +870,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)
>  	 * No need to check return value here, rmap_can_add() can
>  	 * help us to skip pte prefetch later.
>  	 */
> -	mmu_topup_memory_caches(vcpu);
> +	mmu_topup_memcaches(vcpu);
>  
>  	if (!VALID_PAGE(root_hpa)) {
>  		WARN_ON(1);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index c38cc5eb7e73..f5768e5d33f7 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -739,6 +739,15 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool usermode_vcpu_not_eligible);
>  void kvm_flush_remote_tlbs(struct kvm *kvm);
>  void kvm_reload_remote_mmus(struct kvm *kvm);
>  
> +int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
> +			   struct kmem_cache *base_cache, int min);
> +int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache);
> +void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
> +			   struct kmem_cache *cache);
> +int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min);
> +void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc);
> +void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc);
> +
>  bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
>  				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
>  bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
> diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> index 8bf259dae9f6..a314f0f08e22 100644
> --- a/include/linux/kvm_types.h
> +++ b/include/linux/kvm_types.h
> @@ -32,6 +32,7 @@ struct kvm_memslots;
>  
>  enum kvm_mr_change;
>  
> +#include <asm/kvm_types.h>
>  #include <asm/types.h>
>  
>  /*
> @@ -63,4 +64,15 @@ struct gfn_to_hva_cache {
>  	struct kvm_memory_slot *memslot;
>  };
>  
> +#ifdef KVM_NR_MEM_OBJS

While you're renaming the functions, would it make sense to also rename
the define, e.g. KVM_MMU_NR_MEMCACHE_OBJS, or maybe something a little
less verbose.

> +/*
> + * 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_memcache {

Wrapping the kvm_mmu_memcache definition in KVM_NR_MEM_OBJS will break
compilation on any arch that doesn't define KVM_NR_MEM_OBJS.

> +	int nobjs;
> +	void *objects[KVM_NR_MEM_OBJS];
> +};
> +#endif
> +
>  #endif /* __KVM_TYPES_H__ */
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 5ecea812cb6a..ae6454a77aa8 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -285,6 +285,64 @@ void kvm_reload_remote_mmus(struct kvm *kvm)
>  	kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
>  }
>  
> +int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
> +			   struct kmem_cache *base_cache, int min)
> +{
> +	void *obj;
> +
> +	if (cache->nobjs >= min)
> +		return 0;
> +	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> +		obj = kmem_cache_zalloc(base_cache, KVM_MMU_CACHE_GFP);
> +		if (!obj)
> +			return cache->nobjs >= min ? 0 : -ENOMEM;
> +		cache->objects[cache->nobjs++] = obj;
> +	}
> +	return 0;
> +}
> +
> +int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache)
> +{
> +	return cache->nobjs;
> +}
> +
> +void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
> +			   struct kmem_cache *cache)
> +{
> +	while (mc->nobjs)
> +		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
> +}
> +
> +int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min)
> +{
> +	void *page;
> +
> +	if (cache->nobjs >= min)
> +		return 0;
> +	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> +		page = (void *)__get_free_page(KVM_MMU_CACHE_PAGE_GFP);
> +		if (!page)
> +			return cache->nobjs >= min ? 0 : -ENOMEM;
> +		cache->objects[cache->nobjs++] = page;
> +	}
> +	return 0;
> +}
> +
> +void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc)
> +{
> +	while (mc->nobjs)
> +		free_page((unsigned long)mc->objects[--mc->nobjs]);
> +}
> +
> +void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc)
> +{
> +	void *p;
> +
> +	BUG_ON(!mc->nobjs);
> +	p = mc->objects[--mc->nobjs];
> +	return p;
> +}
> +
>  int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
>  {
>  	struct page *page;
> -- 
> 2.18.0
>
Christoffer Dall - Jan. 29, 2019, 2:25 p.m.
On Mon, Jan 28, 2019 at 08:19:56AM -0800, Sean Christopherson wrote:
> On Mon, Jan 28, 2019 at 03:48:41PM +0100, Christoffer Dall wrote:
> > We are currently duplicating the mmu memory cache functionality quite
> > heavily between the architectures that support KVM.  As a first step,
> > move the x86 implementation (which seems to have the most recently
> > maintained version of the mmu memory cache) to common code.
> > 
> > We rename the functions and data types to have a kvm_ prefix for
> > anything exported as a symbol to the rest of the kernel and take the
> > chance to rename memory_cache to memcache to avoid overly long lines.
> 
> It'd be helpful to do the rename it a separate patch so that the move
> really is a straight move of code.
> 
> > This is a bit tedious on the callsites but ends up looking more
> > palatable.
> > 
> > We also introduce an arch-specific kvm_types.h which can be used to
> > define the architecture-specific GFP flags for allocating memory to the
> > memory cache, and to specify how many objects are required in the memory
> > cache.  These are the two points where the current implementations
> > diverge across architectures.  Since kvm_host.h defines structures with
> > fields of the memcache object, we define the memcache structure in
> > kvm_types.h, and we include the architecture-specific kvm_types.h to
> > know the size of object in kvm_host.h.
> > 
> > This patch currently only defines the structure and requires valid
> > defines in the architecture-specific kvm_types.h when KVM_NR_MEM_OBJS is
> > defined.  As we move each architecture to the common implementation,
> > this condition will eventually go away.
> > 
> > Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
> > ---
> >  arch/arm/include/asm/kvm_types.h     |  5 ++
> >  arch/arm64/include/asm/kvm_types.h   |  6 ++
> >  arch/mips/include/asm/kvm_types.h    |  5 ++
> >  arch/powerpc/include/asm/kvm_types.h |  5 ++
> >  arch/s390/include/asm/kvm_types.h    |  5 ++
> >  arch/x86/include/asm/kvm_host.h      | 17 +----
> >  arch/x86/include/asm/kvm_types.h     | 10 +++
> >  arch/x86/kvm/mmu.c                   | 97 ++++++----------------------
> >  arch/x86/kvm/paging_tmpl.h           |  4 +-
> >  include/linux/kvm_host.h             |  9 +++
> >  include/linux/kvm_types.h            | 12 ++++
> >  virt/kvm/kvm_main.c                  | 58 +++++++++++++++++
> >  12 files changed, 139 insertions(+), 94 deletions(-)
> >  create mode 100644 arch/arm/include/asm/kvm_types.h
> >  create mode 100644 arch/arm64/include/asm/kvm_types.h
> >  create mode 100644 arch/mips/include/asm/kvm_types.h
> >  create mode 100644 arch/powerpc/include/asm/kvm_types.h
> >  create mode 100644 arch/s390/include/asm/kvm_types.h
> >  create mode 100644 arch/x86/include/asm/kvm_types.h
> > 
> > diff --git a/arch/arm/include/asm/kvm_types.h b/arch/arm/include/asm/kvm_types.h
> > new file mode 100644
> > index 000000000000..bc389f82e88d
> > --- /dev/null
> > +++ b/arch/arm/include/asm/kvm_types.h
> > @@ -0,0 +1,5 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_ARM_KVM_TYPES_H
> > +#define _ASM_ARM_KVM_TYPES_H
> > +
> > +#endif /* _ASM_ARM_KVM_TYPES_H */
> > diff --git a/arch/arm64/include/asm/kvm_types.h b/arch/arm64/include/asm/kvm_types.h
> > new file mode 100644
> > index 000000000000..d0987007d581
> > --- /dev/null
> > +++ b/arch/arm64/include/asm/kvm_types.h
> > @@ -0,0 +1,6 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_ARM64_KVM_TYPES_H
> > +#define _ASM_ARM64_KVM_TYPES_H
> > +
> > +#endif /* _ASM_ARM64_KVM_TYPES_H */
> > +
> > diff --git a/arch/mips/include/asm/kvm_types.h b/arch/mips/include/asm/kvm_types.h
> > new file mode 100644
> > index 000000000000..5efeb32a5926
> > --- /dev/null
> > +++ b/arch/mips/include/asm/kvm_types.h
> > @@ -0,0 +1,5 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_MIPS_KVM_TYPES_H
> > +#define _ASM_MIPS_KVM_TYPES_H
> > +
> > +#endif /* _ASM_MIPS_KVM_TYPES_H */
> > diff --git a/arch/powerpc/include/asm/kvm_types.h b/arch/powerpc/include/asm/kvm_types.h
> > new file mode 100644
> > index 000000000000..f627eceaa314
> > --- /dev/null
> > +++ b/arch/powerpc/include/asm/kvm_types.h
> > @@ -0,0 +1,5 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_POWERPC_KVM_TYPES_H
> > +#define _ASM_POWERPC_KVM_TYPES_H
> > +
> > +#endif /* _ASM_POWERPC_KVM_TYPES_H */
> > diff --git a/arch/s390/include/asm/kvm_types.h b/arch/s390/include/asm/kvm_types.h
> > new file mode 100644
> > index 000000000000..b66a81f8a354
> > --- /dev/null
> > +++ b/arch/s390/include/asm/kvm_types.h
> > @@ -0,0 +1,5 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_S390_KVM_TYPES_H
> > +#define _ASM_S390_KVM_TYPES_H
> > +
> > +#endif /* _ASM_S390_KVM_TYPES_H */
> > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > index 4660ce90de7f..5c12cba8c2b1 100644
> > --- a/arch/x86/include/asm/kvm_host.h
> > +++ b/arch/x86/include/asm/kvm_host.h
> > @@ -179,8 +179,6 @@ enum {
> >  
> >  #include <asm/kvm_emulate.h>
> >  
> > -#define KVM_NR_MEM_OBJS 40
> > -
> >  #define KVM_NR_DB_REGS	4
> >  
> >  #define DR6_BD		(1 << 13)
> > @@ -238,15 +236,6 @@ enum {
> >  
> >  struct kvm_kernel_irq_routing_entry;
> >  
> > -/*
> > - * 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];
> > -};
> > -
> >  /*
> >   * the pages used as guest page table on soft mmu are tracked by
> >   * kvm_memory_slot.arch.gfn_track which is 16 bits, so the role bits used
> > @@ -600,9 +589,9 @@ 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_page_cache;
> > -	struct kvm_mmu_memory_cache mmu_page_header_cache;
> > +	struct kvm_mmu_memcache mmu_pte_list_desc_cache;
> > +	struct kvm_mmu_memcache mmu_page_cache;
> > +	struct kvm_mmu_memcache mmu_page_header_cache;
> >  
> >  	/*
> >  	 * QEMU userspace and the guest each have their own FPU state.
> > diff --git a/arch/x86/include/asm/kvm_types.h b/arch/x86/include/asm/kvm_types.h
> > new file mode 100644
> > index 000000000000..f71fe5556b6f
> > --- /dev/null
> > +++ b/arch/x86/include/asm/kvm_types.h
> > @@ -0,0 +1,10 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_X86_KVM_TYPES_H
> > +#define _ASM_X86_KVM_TYPES_H
> > +
> > +#define KVM_NR_MEM_OBJS 40
> > +
> > +#define KVM_MMU_CACHE_GFP	GFP_KERNEL
> > +#define KVM_MMU_CACHE_PAGE_GFP	GFP_KERNEL_ACCOUNT
> > +
> > +#endif /* _ASM_X86_KVM_TYPES_H */
> > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > index ce770b446238..cf0024849404 100644
> > --- a/arch/x86/kvm/mmu.c
> > +++ b/arch/x86/kvm/mmu.c
> > @@ -951,94 +951,35 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
> >  	local_irq_enable();
> >  }
> >  
> > -static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
> > -				  struct kmem_cache *base_cache, int min)
> > -{
> > -	void *obj;
> > -
> > -	if (cache->nobjs >= min)
> > -		return 0;
> > -	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> > -		obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
> > -		if (!obj)
> > -			return cache->nobjs >= min ? 0 : -ENOMEM;
> > -		cache->objects[cache->nobjs++] = obj;
> > -	}
> > -	return 0;
> > -}
> > -
> > -static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
> > -{
> > -	return cache->nobjs;
> > -}
> > -
> > -static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
> > -				  struct kmem_cache *cache)
> > -{
> > -	while (mc->nobjs)
> > -		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
> > -}
> > -
> > -static int mmu_topup_memory_cache_page(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);
> > -		if (!page)
> > -			return cache->nobjs >= min ? 0 : -ENOMEM;
> > -		cache->objects[cache->nobjs++] = page;
> > -	}
> > -	return 0;
> > -}
> > -
> > -static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
> > -{
> > -	while (mc->nobjs)
> > -		free_page((unsigned long)mc->objects[--mc->nobjs]);
> > -}
> > -
> > -static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
> > +static int mmu_topup_memcaches(struct kvm_vcpu *vcpu)
> >  {
> >  	int r;
> >  
> > -	r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
> > +	r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
> >  				   pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
> >  	if (r)
> >  		goto out;
> > -	r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
> > +	r = kvm_mmu_topup_memcache_page(&vcpu->arch.mmu_page_cache, 8);
> >  	if (r)
> >  		goto out;
> > -	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
> > +	r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_page_header_cache,
> >  				   mmu_page_header_cache, 4);
> >  out:
> >  	return r;
> >  }
> >  
> > -static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
> > +static void mmu_free_memcaches(struct kvm_vcpu *vcpu)
> >  {
> > -	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
> > +	kvm_mmu_free_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
> >  				pte_list_desc_cache);
> > -	mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
> > -	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
> > +	kvm_mmu_free_memcache_page(&vcpu->arch.mmu_page_cache);
> > +	kvm_mmu_free_memcache(&vcpu->arch.mmu_page_header_cache,
> >  				mmu_page_header_cache);
> >  }
> >  
> > -static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
> > -{
> > -	void *p;
> > -
> > -	BUG_ON(!mc->nobjs);
> > -	p = mc->objects[--mc->nobjs];
> > -	return p;
> > -}
> > -
> >  static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
> >  {
> > -	return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
> > +	return kvm_mmu_memcache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
> >  }
> >  
> >  static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
> > @@ -1358,10 +1299,10 @@ static struct kvm_rmap_head *gfn_to_rmap(struct kvm *kvm, gfn_t gfn,
> >  
> >  static bool rmap_can_add(struct kvm_vcpu *vcpu)
> >  {
> > -	struct kvm_mmu_memory_cache *cache;
> > +	struct kvm_mmu_memcache *cache;
> >  
> >  	cache = &vcpu->arch.mmu_pte_list_desc_cache;
> > -	return mmu_memory_cache_free_objects(cache);
> > +	return kvm_mmu_memcache_free_objects(cache);
> >  }
> >  
> >  static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
> > @@ -2044,10 +1985,10 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
> >  {
> >  	struct kvm_mmu_page *sp;
> >  
> > -	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
> > -	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> > +	sp = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_header_cache);
> > +	sp->spt = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
> >  	if (!direct)
> > -		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> > +		sp->gfns = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
> >  	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
> >  
> >  	/*
> > @@ -3961,7 +3902,7 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
> >  	if (page_fault_handle_page_track(vcpu, error_code, gfn))
> >  		return RET_PF_EMULATE;
> >  
> > -	r = mmu_topup_memory_caches(vcpu);
> > +	r = mmu_topup_memcaches(vcpu);
> >  	if (r)
> >  		return r;
> >  
> > @@ -4090,7 +4031,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
> >  	if (page_fault_handle_page_track(vcpu, error_code, gfn))
> >  		return RET_PF_EMULATE;
> >  
> > -	r = mmu_topup_memory_caches(vcpu);
> > +	r = mmu_topup_memcaches(vcpu);
> >  	if (r)
> >  		return r;
> >  
> > @@ -5062,7 +5003,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
> >  {
> >  	int r;
> >  
> > -	r = mmu_topup_memory_caches(vcpu);
> > +	r = mmu_topup_memcaches(vcpu);
> >  	if (r)
> >  		goto out;
> >  	r = mmu_alloc_roots(vcpu);
> > @@ -5240,7 +5181,7 @@ static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
> >  	 * or not since pte prefetch is skiped if it does not have
> >  	 * enough objects in the cache.
> >  	 */
> > -	mmu_topup_memory_caches(vcpu);
> > +	mmu_topup_memcaches(vcpu);
> >  
> >  	spin_lock(&vcpu->kvm->mmu_lock);
> >  
> > @@ -6052,7 +5993,7 @@ void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
> >  {
> >  	kvm_mmu_unload(vcpu);
> >  	free_mmu_pages(vcpu);
> > -	mmu_free_memory_caches(vcpu);
> > +	mmu_free_memcaches(vcpu);
> >  }
> >  
> >  void kvm_mmu_module_exit(void)
> > diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> > index 6bdca39829bc..c32b603639a9 100644
> > --- a/arch/x86/kvm/paging_tmpl.h
> > +++ b/arch/x86/kvm/paging_tmpl.h
> > @@ -747,7 +747,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
> >  
> >  	pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
> >  
> > -	r = mmu_topup_memory_caches(vcpu);
> > +	r = mmu_topup_memcaches(vcpu);
> >  	if (r)
> >  		return r;
> >  
> > @@ -870,7 +870,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)
> >  	 * No need to check return value here, rmap_can_add() can
> >  	 * help us to skip pte prefetch later.
> >  	 */
> > -	mmu_topup_memory_caches(vcpu);
> > +	mmu_topup_memcaches(vcpu);
> >  
> >  	if (!VALID_PAGE(root_hpa)) {
> >  		WARN_ON(1);
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index c38cc5eb7e73..f5768e5d33f7 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -739,6 +739,15 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool usermode_vcpu_not_eligible);
> >  void kvm_flush_remote_tlbs(struct kvm *kvm);
> >  void kvm_reload_remote_mmus(struct kvm *kvm);
> >  
> > +int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
> > +			   struct kmem_cache *base_cache, int min);
> > +int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache);
> > +void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
> > +			   struct kmem_cache *cache);
> > +int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min);
> > +void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc);
> > +void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc);
> > +
> >  bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
> >  				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
> >  bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
> > diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> > index 8bf259dae9f6..a314f0f08e22 100644
> > --- a/include/linux/kvm_types.h
> > +++ b/include/linux/kvm_types.h
> > @@ -32,6 +32,7 @@ struct kvm_memslots;
> >  
> >  enum kvm_mr_change;
> >  
> > +#include <asm/kvm_types.h>
> >  #include <asm/types.h>
> >  
> >  /*
> > @@ -63,4 +64,15 @@ struct gfn_to_hva_cache {
> >  	struct kvm_memory_slot *memslot;
> >  };
> >  
> > +#ifdef KVM_NR_MEM_OBJS
> 
> While you're renaming the functions, would it make sense to also rename
> the define, e.g. KVM_MMU_NR_MEMCACHE_OBJS, or maybe something a little
> less verbose.
> 
> > +/*
> > + * 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_memcache {
> 
> Wrapping the kvm_mmu_memcache definition in KVM_NR_MEM_OBJS will break
> compilation on any arch that doesn't define KVM_NR_MEM_OBJS.
> 

Yes, this is obviously broken.

I'll respin with your comments addressed.

Thanks,

    Christoffer

Patch

diff --git a/arch/arm/include/asm/kvm_types.h b/arch/arm/include/asm/kvm_types.h
new file mode 100644
index 000000000000..bc389f82e88d
--- /dev/null
+++ b/arch/arm/include/asm/kvm_types.h
@@ -0,0 +1,5 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARM_KVM_TYPES_H
+#define _ASM_ARM_KVM_TYPES_H
+
+#endif /* _ASM_ARM_KVM_TYPES_H */
diff --git a/arch/arm64/include/asm/kvm_types.h b/arch/arm64/include/asm/kvm_types.h
new file mode 100644
index 000000000000..d0987007d581
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_types.h
@@ -0,0 +1,6 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARM64_KVM_TYPES_H
+#define _ASM_ARM64_KVM_TYPES_H
+
+#endif /* _ASM_ARM64_KVM_TYPES_H */
+
diff --git a/arch/mips/include/asm/kvm_types.h b/arch/mips/include/asm/kvm_types.h
new file mode 100644
index 000000000000..5efeb32a5926
--- /dev/null
+++ b/arch/mips/include/asm/kvm_types.h
@@ -0,0 +1,5 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_MIPS_KVM_TYPES_H
+#define _ASM_MIPS_KVM_TYPES_H
+
+#endif /* _ASM_MIPS_KVM_TYPES_H */
diff --git a/arch/powerpc/include/asm/kvm_types.h b/arch/powerpc/include/asm/kvm_types.h
new file mode 100644
index 000000000000..f627eceaa314
--- /dev/null
+++ b/arch/powerpc/include/asm/kvm_types.h
@@ -0,0 +1,5 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_KVM_TYPES_H
+#define _ASM_POWERPC_KVM_TYPES_H
+
+#endif /* _ASM_POWERPC_KVM_TYPES_H */
diff --git a/arch/s390/include/asm/kvm_types.h b/arch/s390/include/asm/kvm_types.h
new file mode 100644
index 000000000000..b66a81f8a354
--- /dev/null
+++ b/arch/s390/include/asm/kvm_types.h
@@ -0,0 +1,5 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_KVM_TYPES_H
+#define _ASM_S390_KVM_TYPES_H
+
+#endif /* _ASM_S390_KVM_TYPES_H */
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4660ce90de7f..5c12cba8c2b1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -179,8 +179,6 @@  enum {
 
 #include <asm/kvm_emulate.h>
 
-#define KVM_NR_MEM_OBJS 40
-
 #define KVM_NR_DB_REGS	4
 
 #define DR6_BD		(1 << 13)
@@ -238,15 +236,6 @@  enum {
 
 struct kvm_kernel_irq_routing_entry;
 
-/*
- * 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];
-};
-
 /*
  * the pages used as guest page table on soft mmu are tracked by
  * kvm_memory_slot.arch.gfn_track which is 16 bits, so the role bits used
@@ -600,9 +589,9 @@  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_page_cache;
-	struct kvm_mmu_memory_cache mmu_page_header_cache;
+	struct kvm_mmu_memcache mmu_pte_list_desc_cache;
+	struct kvm_mmu_memcache mmu_page_cache;
+	struct kvm_mmu_memcache mmu_page_header_cache;
 
 	/*
 	 * QEMU userspace and the guest each have their own FPU state.
diff --git a/arch/x86/include/asm/kvm_types.h b/arch/x86/include/asm/kvm_types.h
new file mode 100644
index 000000000000..f71fe5556b6f
--- /dev/null
+++ b/arch/x86/include/asm/kvm_types.h
@@ -0,0 +1,10 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_KVM_TYPES_H
+#define _ASM_X86_KVM_TYPES_H
+
+#define KVM_NR_MEM_OBJS 40
+
+#define KVM_MMU_CACHE_GFP	GFP_KERNEL
+#define KVM_MMU_CACHE_PAGE_GFP	GFP_KERNEL_ACCOUNT
+
+#endif /* _ASM_X86_KVM_TYPES_H */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ce770b446238..cf0024849404 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -951,94 +951,35 @@  static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
 	local_irq_enable();
 }
 
-static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
-				  struct kmem_cache *base_cache, int min)
-{
-	void *obj;
-
-	if (cache->nobjs >= min)
-		return 0;
-	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
-		obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
-		if (!obj)
-			return cache->nobjs >= min ? 0 : -ENOMEM;
-		cache->objects[cache->nobjs++] = obj;
-	}
-	return 0;
-}
-
-static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
-{
-	return cache->nobjs;
-}
-
-static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
-				  struct kmem_cache *cache)
-{
-	while (mc->nobjs)
-		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
-}
-
-static int mmu_topup_memory_cache_page(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);
-		if (!page)
-			return cache->nobjs >= min ? 0 : -ENOMEM;
-		cache->objects[cache->nobjs++] = page;
-	}
-	return 0;
-}
-
-static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
-{
-	while (mc->nobjs)
-		free_page((unsigned long)mc->objects[--mc->nobjs]);
-}
-
-static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
+static int mmu_topup_memcaches(struct kvm_vcpu *vcpu)
 {
 	int r;
 
-	r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
+	r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
 				   pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
 	if (r)
 		goto out;
-	r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
+	r = kvm_mmu_topup_memcache_page(&vcpu->arch.mmu_page_cache, 8);
 	if (r)
 		goto out;
-	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
+	r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_page_header_cache,
 				   mmu_page_header_cache, 4);
 out:
 	return r;
 }
 
-static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
+static void mmu_free_memcaches(struct kvm_vcpu *vcpu)
 {
-	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
+	kvm_mmu_free_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
 				pte_list_desc_cache);
-	mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
-	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
+	kvm_mmu_free_memcache_page(&vcpu->arch.mmu_page_cache);
+	kvm_mmu_free_memcache(&vcpu->arch.mmu_page_header_cache,
 				mmu_page_header_cache);
 }
 
-static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
-{
-	void *p;
-
-	BUG_ON(!mc->nobjs);
-	p = mc->objects[--mc->nobjs];
-	return p;
-}
-
 static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
 {
-	return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
+	return kvm_mmu_memcache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
 }
 
 static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
@@ -1358,10 +1299,10 @@  static struct kvm_rmap_head *gfn_to_rmap(struct kvm *kvm, gfn_t gfn,
 
 static bool rmap_can_add(struct kvm_vcpu *vcpu)
 {
-	struct kvm_mmu_memory_cache *cache;
+	struct kvm_mmu_memcache *cache;
 
 	cache = &vcpu->arch.mmu_pte_list_desc_cache;
-	return mmu_memory_cache_free_objects(cache);
+	return kvm_mmu_memcache_free_objects(cache);
 }
 
 static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
@@ -2044,10 +1985,10 @@  static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
 {
 	struct kvm_mmu_page *sp;
 
-	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
-	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
+	sp = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_header_cache);
+	sp->spt = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
 	if (!direct)
-		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
+		sp->gfns = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
 	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 
 	/*
@@ -3961,7 +3902,7 @@  static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 	if (page_fault_handle_page_track(vcpu, error_code, gfn))
 		return RET_PF_EMULATE;
 
-	r = mmu_topup_memory_caches(vcpu);
+	r = mmu_topup_memcaches(vcpu);
 	if (r)
 		return r;
 
@@ -4090,7 +4031,7 @@  static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
 	if (page_fault_handle_page_track(vcpu, error_code, gfn))
 		return RET_PF_EMULATE;
 
-	r = mmu_topup_memory_caches(vcpu);
+	r = mmu_topup_memcaches(vcpu);
 	if (r)
 		return r;
 
@@ -5062,7 +5003,7 @@  int kvm_mmu_load(struct kvm_vcpu *vcpu)
 {
 	int r;
 
-	r = mmu_topup_memory_caches(vcpu);
+	r = mmu_topup_memcaches(vcpu);
 	if (r)
 		goto out;
 	r = mmu_alloc_roots(vcpu);
@@ -5240,7 +5181,7 @@  static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 	 * or not since pte prefetch is skiped if it does not have
 	 * enough objects in the cache.
 	 */
-	mmu_topup_memory_caches(vcpu);
+	mmu_topup_memcaches(vcpu);
 
 	spin_lock(&vcpu->kvm->mmu_lock);
 
@@ -6052,7 +5993,7 @@  void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
 {
 	kvm_mmu_unload(vcpu);
 	free_mmu_pages(vcpu);
-	mmu_free_memory_caches(vcpu);
+	mmu_free_memcaches(vcpu);
 }
 
 void kvm_mmu_module_exit(void)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 6bdca39829bc..c32b603639a9 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -747,7 +747,7 @@  static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
 
 	pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
 
-	r = mmu_topup_memory_caches(vcpu);
+	r = mmu_topup_memcaches(vcpu);
 	if (r)
 		return r;
 
@@ -870,7 +870,7 @@  static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)
 	 * No need to check return value here, rmap_can_add() can
 	 * help us to skip pte prefetch later.
 	 */
-	mmu_topup_memory_caches(vcpu);
+	mmu_topup_memcaches(vcpu);
 
 	if (!VALID_PAGE(root_hpa)) {
 		WARN_ON(1);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c38cc5eb7e73..f5768e5d33f7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -739,6 +739,15 @@  void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool usermode_vcpu_not_eligible);
 void kvm_flush_remote_tlbs(struct kvm *kvm);
 void kvm_reload_remote_mmus(struct kvm *kvm);
 
+int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
+			   struct kmem_cache *base_cache, int min);
+int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache);
+void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
+			   struct kmem_cache *cache);
+int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min);
+void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc);
+void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc);
+
 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
 				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
index 8bf259dae9f6..a314f0f08e22 100644
--- a/include/linux/kvm_types.h
+++ b/include/linux/kvm_types.h
@@ -32,6 +32,7 @@  struct kvm_memslots;
 
 enum kvm_mr_change;
 
+#include <asm/kvm_types.h>
 #include <asm/types.h>
 
 /*
@@ -63,4 +64,15 @@  struct gfn_to_hva_cache {
 	struct kvm_memory_slot *memslot;
 };
 
+#ifdef KVM_NR_MEM_OBJS
+/*
+ * 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_memcache {
+	int nobjs;
+	void *objects[KVM_NR_MEM_OBJS];
+};
+#endif
+
 #endif /* __KVM_TYPES_H__ */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5ecea812cb6a..ae6454a77aa8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -285,6 +285,64 @@  void kvm_reload_remote_mmus(struct kvm *kvm)
 	kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
 }
 
+int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
+			   struct kmem_cache *base_cache, int min)
+{
+	void *obj;
+
+	if (cache->nobjs >= min)
+		return 0;
+	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
+		obj = kmem_cache_zalloc(base_cache, KVM_MMU_CACHE_GFP);
+		if (!obj)
+			return cache->nobjs >= min ? 0 : -ENOMEM;
+		cache->objects[cache->nobjs++] = obj;
+	}
+	return 0;
+}
+
+int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache)
+{
+	return cache->nobjs;
+}
+
+void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
+			   struct kmem_cache *cache)
+{
+	while (mc->nobjs)
+		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
+}
+
+int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min)
+{
+	void *page;
+
+	if (cache->nobjs >= min)
+		return 0;
+	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
+		page = (void *)__get_free_page(KVM_MMU_CACHE_PAGE_GFP);
+		if (!page)
+			return cache->nobjs >= min ? 0 : -ENOMEM;
+		cache->objects[cache->nobjs++] = page;
+	}
+	return 0;
+}
+
+void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc)
+{
+	while (mc->nobjs)
+		free_page((unsigned long)mc->objects[--mc->nobjs]);
+}
+
+void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc)
+{
+	void *p;
+
+	BUG_ON(!mc->nobjs);
+	p = mc->objects[--mc->nobjs];
+	return p;
+}
+
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
 	struct page *page;