KVM: x86/mmu: Make __GFP_ZERO a property of the memory cache (5f6078f9) · Commits · 戴 / test

Add a gfp_zero flag to 'struct kvm_mmu_memory_cache' and use it to control __GFP_ZERO instead of hardcoding a call to kmem_cache_zalloc(). A future patch needs such a flag for the __get_free_page() path, as gfn arrays do not need/want the allocator to zero the memory. Convert the kmem_cache paths to __GFP_ZERO now so as to avoid a weird and inconsistent API in the future. No functional change intended. Reviewed-by:

Ben Gardon <bgardon@google.com> Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200703023545.8771-11-sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -251,6 +251,7 @@ struct kvm_kernel_irq_routing_entry;
		*/
		struct kvm_mmu_memory_cache {
		int nobjs;
		gfp_t gfp_zero;
		struct kmem_cache *kmem_cache;
		void *objects[KVM_NR_MEM_OBJS];
		};

arch/x86/kvm/mmu/mmu.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -1064,8 +1064,10 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
		static inline void mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache mc,
		gfp_t gfp_flags)
		{
		gfp_flags \|= mc->gfp_zero;

		if (mc->kmem_cache)
		return kmem_cache_zalloc(mc->kmem_cache, gfp_flags);
		return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
		else
		return (void *)__get_free_page(gfp_flags);
		}
		@@ -5701,7 +5703,10 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
		int ret;

		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->arch.mmu = &vcpu->arch.root_mmu;
		vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;

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