KVM: x86/mmu: Make __GFP_ZERO a property of the memory cache

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>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 01f5c15..9d41eb5 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -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];
 };

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a8fc17a..6e57044 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -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;