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Commit d3d25b04 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: MMU: Use slab caches for shadow pages and their headers 



Use slab caches instead of a simple custom list.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 8d728203

drivers/kvm/kvm.h

+2 −2
Original line number Diff line number Diff line
@@ -299,12 +299,12 @@ struct kvm_vcpu { 
	struct vmx_msr_entry *guest_msrs;

	struct vmx_msr_entry *host_msrs;



	struct list_head free_pages;

	struct kvm_mmu_page page_header_buf[KVM_NUM_MMU_PAGES];

	struct kvm_mmu mmu;



	struct kvm_mmu_memory_cache mmu_pte_chain_cache;

	struct kvm_mmu_memory_cache mmu_rmap_desc_cache;

	struct kvm_mmu_memory_cache mmu_page_cache;

	struct kvm_mmu_memory_cache mmu_page_header_cache;



	gfn_t last_pt_write_gfn;

	int   last_pt_write_count;

drivers/kvm/kvm_main.c

+0 −1
Original line number Diff line number Diff line
@@ -326,7 +326,6 @@ static struct kvm *kvm_create_vm(void) 
		vcpu->cpu = -1;

		vcpu->kvm = kvm;

		vcpu->mmu.root_hpa = INVALID_PAGE;

		INIT_LIST_HEAD(&vcpu->free_pages);

		spin_lock(&kvm_lock);

		list_add(&kvm->vm_list, &vm_list);

		spin_unlock(&kvm_lock);

drivers/kvm/mmu.c

+39 −25
Original line number Diff line number Diff line
@@ -165,6 +165,8 @@ struct kvm_rmap_desc { 


static struct kmem_cache *pte_chain_cache;

static struct kmem_cache *rmap_desc_cache;

static struct kmem_cache *mmu_page_cache;

static struct kmem_cache *mmu_page_header_cache;



static int is_write_protection(struct kvm_vcpu *vcpu)

{
@@ -235,6 +237,14 @@ static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags) 
		goto out;

	r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,

				   rmap_desc_cache, 1, gfp_flags);

	if (r)

		goto out;

	r = mmu_topup_memory_cache(&vcpu->mmu_page_cache,

				   mmu_page_cache, 4, gfp_flags);

	if (r)

		goto out;

	r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,

				   mmu_page_header_cache, 4, gfp_flags);

out:

	return r;

}
@@ -258,6 +268,8 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) 
{

	mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);

	mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache);

	mmu_free_memory_cache(&vcpu->mmu_page_cache);

	mmu_free_memory_cache(&vcpu->mmu_page_header_cache);

}



static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
@@ -458,7 +470,9 @@ static void kvm_mmu_free_page(struct kvm_vcpu *vcpu, 
			      struct kvm_mmu_page *page_head)

{

	ASSERT(is_empty_shadow_page(page_head->spt));

	list_move(&page_head->link, &vcpu->free_pages);

	list_del(&page_head->link);

	mmu_memory_cache_free(&vcpu->mmu_page_cache, page_head->spt);

	mmu_memory_cache_free(&vcpu->mmu_page_header_cache, page_head);

	++vcpu->kvm->n_free_mmu_pages;

}
@@ -472,11 +486,14 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, 
{

	struct kvm_mmu_page *page;



	if (list_empty(&vcpu->free_pages))

	if (!vcpu->kvm->n_free_mmu_pages)

		return NULL;



	page = list_entry(vcpu->free_pages.next, struct kvm_mmu_page, link);

	list_move(&page->link, &vcpu->kvm->active_mmu_pages);

	page = mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache,

				      sizeof *page);

	page->spt = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);

	set_page_private(virt_to_page(page->spt), (unsigned long)page);

	list_add(&page->link, &vcpu->kvm->active_mmu_pages);

	ASSERT(is_empty_shadow_page(page->spt));

	page->slot_bitmap = 0;

	page->multimapped = 0;
@@ -1083,6 +1100,7 @@ static int init_kvm_mmu(struct kvm_vcpu *vcpu) 
	ASSERT(vcpu);

	ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));



	mmu_topup_memory_caches(vcpu);

	if (!is_paging(vcpu))

		return nonpaging_init_context(vcpu);

	else if (is_long_mode(vcpu))
@@ -1256,13 +1274,6 @@ static void free_mmu_pages(struct kvm_vcpu *vcpu) 
				    struct kvm_mmu_page, link);

		kvm_mmu_zap_page(vcpu, page);

	}

	while (!list_empty(&vcpu->free_pages)) {

		page = list_entry(vcpu->free_pages.next,

				  struct kvm_mmu_page, link);

		list_del(&page->link);

		free_page((unsigned long)page->spt);

		page->spt = NULL;

	}

	free_page((unsigned long)vcpu->mmu.pae_root);

}
@@ -1273,18 +1284,7 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu) 


	ASSERT(vcpu);



	for (i = 0; i < KVM_NUM_MMU_PAGES; i++) {

		struct kvm_mmu_page *page_header = &vcpu->page_header_buf[i];



		INIT_LIST_HEAD(&page_header->link);

		if ((page = alloc_page(GFP_KERNEL)) == NULL)

			goto error_1;

		set_page_private(page, (unsigned long)page_header);

		page_header->spt = page_address(page);

		memset(page_header->spt, 0, PAGE_SIZE);

		list_add(&page_header->link, &vcpu->free_pages);

		++vcpu->kvm->n_free_mmu_pages;

	}

	vcpu->kvm->n_free_mmu_pages = KVM_NUM_MMU_PAGES;



	/*

	 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
@@ -1309,7 +1309,6 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) 
{

	ASSERT(vcpu);

	ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));

	ASSERT(list_empty(&vcpu->free_pages));



	return alloc_mmu_pages(vcpu);

}
@@ -1318,7 +1317,6 @@ int kvm_mmu_setup(struct kvm_vcpu *vcpu) 
{

	ASSERT(vcpu);

	ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));

	ASSERT(!list_empty(&vcpu->free_pages));



	return init_kvm_mmu(vcpu);

}
@@ -1377,6 +1375,10 @@ void kvm_mmu_module_exit(void) 
		kmem_cache_destroy(pte_chain_cache);

	if (rmap_desc_cache)

		kmem_cache_destroy(rmap_desc_cache);

	if (mmu_page_cache)

		kmem_cache_destroy(mmu_page_cache);

	if (mmu_page_header_cache)

		kmem_cache_destroy(mmu_page_header_cache);

}



int kvm_mmu_module_init(void)
@@ -1392,6 +1394,18 @@ int kvm_mmu_module_init(void) 
	if (!rmap_desc_cache)

		goto nomem;



	mmu_page_cache = kmem_cache_create("kvm_mmu_page",

					   PAGE_SIZE,

					   PAGE_SIZE, 0, NULL, NULL);

	if (!mmu_page_cache)

		goto nomem;



	mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",

						  sizeof(struct kvm_mmu_page),

						  0, 0, NULL, NULL);

	if (!mmu_page_header_cache)

		goto nomem;



	return 0;



nomem: