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Date:   Thu, 23 Mar 2023 15:23:30 -0700
From:   David Matlack <dmatlack@google.com>
To:     Vipin Sharma <vipinsh@google.com>
Cc:     seanjc@google.com, pbonzini@redhat.com, bgardon@google.com,
        jmattson@google.com, mizhang@google.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [Patch v4 13/18] KVM: mmu: Add common initialization logic for
 struct kvm_mmu_memory_cache{}
Message-ID: <ZBzRYgC0IWiZy7PI@google.com>
References: <20230306224127.1689967-1-vipinsh@google.com>
 <20230306224127.1689967-14-vipinsh@google.com>
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On Mon, Mar 06, 2023 at 02:41:22PM -0800, Vipin Sharma wrote:
> Add macros and function to make common logic for struct
> kvm_mmu_memory_cache{} declaration and initialization.
> 
> Any user which wants different values in struct kvm_mmu_memory_cache{}
> will overwrite the default values explicitly after the initialization.
> 
> Suggested-by: David Matlack <dmatlack@google.com>
> Signed-off-by: Vipin Sharma <vipinsh@google.com>
> ---
>  arch/arm64/kvm/arm.c      |  1 +
>  arch/arm64/kvm/mmu.c      |  3 ++-
>  arch/riscv/kvm/mmu.c      |  9 +++++----
>  arch/riscv/kvm/vcpu.c     |  1 +

MIPS also has cache (git grep "struct kvm_mmu_memory_cache").

>  arch/x86/kvm/mmu/mmu.c    |  8 ++++++++
>  include/linux/kvm_types.h | 10 ++++++++++
>  6 files changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 3bd732eaf087..2b3d88e4ace8 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -330,6 +330,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>  	vcpu->arch.target = -1;
>  	bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache);
>  	vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
>  
>  	/*
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 7113587222ff..8a56f071ca66 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -895,7 +895,7 @@ 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 = { .gfp_zero = __GFP_ZERO };
> +	KVM_MMU_MEMORY_CACHE(cache);

nit: DEFINE_KVM_MMU_MEMORY_CACHE()

(Based on similar existing macros in the kernel, e.g. DEFINE_MUTEX(),
DEFINE_TIMER().)

>  	struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
>  	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
>  				     KVM_PGTABLE_PROT_R |
> @@ -904,6 +904,7 @@ 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;
>  
> diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> index 78211aed36fa..bdd8c17958dd 100644
> --- a/arch/riscv/kvm/mmu.c
> +++ b/arch/riscv/kvm/mmu.c
> @@ -351,10 +351,11 @@ int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
>  	int ret = 0;
>  	unsigned long pfn;
>  	phys_addr_t addr, end;
> -	struct kvm_mmu_memory_cache pcache = {
> -		.gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
> -		.gfp_zero = __GFP_ZERO,
> -	};
> +	KVM_MMU_MEMORY_CACHE(pcache);
> +
> +	pcache.gfp_zero = __GFP_ZERO;
> +	if (in_atomic)
> +		pcache.gfp_custom = GFP_ATOMIC | __GFP_ACCOUNT;
>  
>  	end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
>  	pfn = __phys_to_pfn(hpa);
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 7d010b0be54e..bc743e9122d1 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -163,6 +163,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>  
>  	/* Mark this VCPU never ran */
>  	vcpu->arch.ran_atleast_once = false;
> +	INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache);
>  	vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
>  	bitmap_zero(vcpu->arch.isa, RISCV_ISA_EXT_MAX);
>  
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index a4bf2e433030..b706087ef74e 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5961,15 +5961,20 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
>  {
>  	int ret;
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_pte_list_desc_cache);
>  	vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
>  	vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_header_cache);
>  	vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
>  	vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadow_page_cache);
>  	vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
>  	mutex_init(&vcpu->arch.mmu_shadow_page_cache_lock);
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadowed_info_cache);
> +
>  	vcpu->arch.mmu = &vcpu->arch.root_mmu;
>  	vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
>  
> @@ -6131,11 +6136,14 @@ int kvm_mmu_init_vm(struct kvm *kvm)
>  	node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
>  	kvm_page_track_register_notifier(kvm, node);
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_page_header_cache);
>  	kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
>  	kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO;
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_shadow_page_cache);
>  	kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO;
>  
> +	INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_desc_cache);
>  	kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache;
>  	kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO;
>  
> diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> index 2728d49bbdf6..192516eeccac 100644
> --- a/include/linux/kvm_types.h
> +++ b/include/linux/kvm_types.h
> @@ -98,6 +98,16 @@ struct kvm_mmu_memory_cache {
>  	int capacity;
>  	void **objects;
>  };
> +
> +#define KVM_MMU_MEMORY_CACHE_INIT() { }
> +
> +#define KVM_MMU_MEMORY_CACHE(_name) \
> +		struct kvm_mmu_memory_cache _name = KVM_MMU_MEMORY_CACHE_INIT()

nit: There's an extra tab here.

> +
> +static inline void INIT_KVM_MMU_MEMORY_CACHE(struct kvm_mmu_memory_cache *cache)
> +{
> +	*cache = (struct kvm_mmu_memory_cache)KVM_MMU_MEMORY_CACHE_INIT();
> +}
>  #endif
>  
>  #define HALT_POLL_HIST_COUNT			32
> -- 
> 2.40.0.rc0.216.gc4246ad0f0-goog
>