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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
s390/mm: add reference counter to gmap structure
Let's use a reference counter mechanism to control the lifetime of gmap structures. This will be needed for further changes related to gmap shadows. Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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b2d73b2a0a
commit
6ea427bbbd
3 changed files with 85 additions and 30 deletions
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@ -15,6 +15,7 @@
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* @guest_to_host: radix tree with guest to host address translation
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* @host_to_guest: radix tree with pointer to segment table entries
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* @guest_table_lock: spinlock to protect all entries in the guest page table
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* @ref_count: reference counter for the gmap structure
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* @table: pointer to the page directory
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* @asce: address space control element for gmap page table
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* @pfault_enabled: defines if pfaults are applicable for the guest
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@ -26,6 +27,7 @@ struct gmap {
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struct radix_tree_root guest_to_host;
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struct radix_tree_root host_to_guest;
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spinlock_t guest_table_lock;
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atomic_t ref_count;
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unsigned long *table;
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unsigned long asce;
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unsigned long asce_end;
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@ -44,8 +46,11 @@ struct gmap_notifier {
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unsigned long end);
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};
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struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit);
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void gmap_free(struct gmap *gmap);
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struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit);
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void gmap_remove(struct gmap *gmap);
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struct gmap *gmap_get(struct gmap *gmap);
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void gmap_put(struct gmap *gmap);
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void gmap_enable(struct gmap *gmap);
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void gmap_disable(struct gmap *gmap);
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int gmap_map_segment(struct gmap *gmap, unsigned long from,
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@ -532,20 +532,20 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att
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if (!new_limit)
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return -EINVAL;
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/* gmap_alloc takes last usable address */
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/* gmap_create takes last usable address */
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if (new_limit != KVM_S390_NO_MEM_LIMIT)
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new_limit -= 1;
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ret = -EBUSY;
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mutex_lock(&kvm->lock);
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if (!kvm->created_vcpus) {
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/* gmap_alloc will round the limit up */
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struct gmap *new = gmap_alloc(current->mm, new_limit);
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/* gmap_create will round the limit up */
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struct gmap *new = gmap_create(current->mm, new_limit);
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if (!new) {
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ret = -ENOMEM;
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} else {
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gmap_free(kvm->arch.gmap);
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gmap_remove(kvm->arch.gmap);
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new->private = kvm;
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kvm->arch.gmap = new;
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ret = 0;
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@ -1394,7 +1394,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
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else
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kvm->arch.mem_limit = min_t(unsigned long, TASK_MAX_SIZE,
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sclp.hamax + 1);
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kvm->arch.gmap = gmap_alloc(current->mm, kvm->arch.mem_limit - 1);
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kvm->arch.gmap = gmap_create(current->mm, kvm->arch.mem_limit - 1);
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if (!kvm->arch.gmap)
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goto out_err;
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kvm->arch.gmap->private = kvm;
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@ -1427,7 +1427,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
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sca_del_vcpu(vcpu);
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if (kvm_is_ucontrol(vcpu->kvm))
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gmap_free(vcpu->arch.gmap);
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gmap_remove(vcpu->arch.gmap);
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if (vcpu->kvm->arch.use_cmma)
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kvm_s390_vcpu_unsetup_cmma(vcpu);
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@ -1460,7 +1460,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
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debug_unregister(kvm->arch.dbf);
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free_page((unsigned long)kvm->arch.sie_page2);
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if (!kvm_is_ucontrol(kvm))
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gmap_free(kvm->arch.gmap);
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gmap_remove(kvm->arch.gmap);
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kvm_s390_destroy_adapters(kvm);
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kvm_s390_clear_float_irqs(kvm);
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KVM_EVENT(3, "vm 0x%pK destroyed", kvm);
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@ -1469,7 +1469,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
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/* Section: vcpu related */
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static int __kvm_ucontrol_vcpu_init(struct kvm_vcpu *vcpu)
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{
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vcpu->arch.gmap = gmap_alloc(current->mm, -1UL);
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vcpu->arch.gmap = gmap_create(current->mm, -1UL);
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if (!vcpu->arch.gmap)
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return -ENOMEM;
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vcpu->arch.gmap->private = vcpu->kvm;
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@ -21,13 +21,13 @@
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#include <asm/tlb.h>
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/**
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* gmap_alloc - allocate a guest address space
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* gmap_alloc - allocate and initialize a guest address space
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* @mm: pointer to the parent mm_struct
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* @limit: maximum address of the gmap address space
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*
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* Returns a guest address space structure.
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*/
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struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit)
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static struct gmap *gmap_alloc(unsigned long limit)
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{
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struct gmap *gmap;
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struct page *page;
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@ -58,7 +58,7 @@ struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit)
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INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
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INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
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spin_lock_init(&gmap->guest_table_lock);
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gmap->mm = mm;
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atomic_set(&gmap->ref_count, 1);
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page = alloc_pages(GFP_KERNEL, 2);
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if (!page)
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goto out_free;
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@ -70,9 +70,6 @@ struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit)
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gmap->asce = atype | _ASCE_TABLE_LENGTH |
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_ASCE_USER_BITS | __pa(table);
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gmap->asce_end = limit;
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spin_lock(&mm->context.gmap_lock);
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list_add_rcu(&gmap->list, &mm->context.gmap_list);
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spin_unlock(&mm->context.gmap_lock);
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return gmap;
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out_free:
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@ -80,7 +77,28 @@ struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit)
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out:
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return NULL;
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}
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EXPORT_SYMBOL_GPL(gmap_alloc);
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/**
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* gmap_create - create a guest address space
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* @mm: pointer to the parent mm_struct
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* @limit: maximum size of the gmap address space
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*
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* Returns a guest address space structure.
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*/
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struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
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{
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struct gmap *gmap;
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gmap = gmap_alloc(limit);
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if (!gmap)
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return NULL;
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gmap->mm = mm;
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spin_lock(&mm->context.gmap_lock);
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list_add_rcu(&gmap->list, &mm->context.gmap_list);
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spin_unlock(&mm->context.gmap_lock);
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return gmap;
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}
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EXPORT_SYMBOL_GPL(gmap_create);
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static void gmap_flush_tlb(struct gmap *gmap)
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{
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@ -118,21 +136,10 @@ static void gmap_radix_tree_free(struct radix_tree_root *root)
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* gmap_free - free a guest address space
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* @gmap: pointer to the guest address space structure
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*/
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void gmap_free(struct gmap *gmap)
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static void gmap_free(struct gmap *gmap)
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{
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struct page *page, *next;
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/* Flush tlb. */
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if (MACHINE_HAS_IDTE)
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__tlb_flush_asce(gmap->mm, gmap->asce);
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else
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__tlb_flush_global();
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spin_lock(&gmap->mm->context.gmap_lock);
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list_del_rcu(&gmap->list);
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spin_unlock(&gmap->mm->context.gmap_lock);
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synchronize_rcu();
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/* Free all segment & region tables. */
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list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
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__free_pages(page, 2);
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@ -140,7 +147,50 @@ void gmap_free(struct gmap *gmap)
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gmap_radix_tree_free(&gmap->host_to_guest);
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kfree(gmap);
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}
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EXPORT_SYMBOL_GPL(gmap_free);
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/**
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* gmap_get - increase reference counter for guest address space
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* @gmap: pointer to the guest address space structure
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*
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* Returns the gmap pointer
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*/
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struct gmap *gmap_get(struct gmap *gmap)
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{
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atomic_inc(&gmap->ref_count);
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return gmap;
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}
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EXPORT_SYMBOL_GPL(gmap_get);
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/**
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* gmap_put - decrease reference counter for guest address space
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* @gmap: pointer to the guest address space structure
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*
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* If the reference counter reaches zero the guest address space is freed.
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*/
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void gmap_put(struct gmap *gmap)
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{
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if (atomic_dec_return(&gmap->ref_count) == 0)
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gmap_free(gmap);
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}
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EXPORT_SYMBOL_GPL(gmap_put);
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/**
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* gmap_remove - remove a guest address space but do not free it yet
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* @gmap: pointer to the guest address space structure
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*/
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void gmap_remove(struct gmap *gmap)
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{
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/* Flush tlb. */
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gmap_flush_tlb(gmap);
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/* Remove gmap from the pre-mm list */
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spin_lock(&gmap->mm->context.gmap_lock);
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list_del_rcu(&gmap->list);
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spin_unlock(&gmap->mm->context.gmap_lock);
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synchronize_rcu();
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/* Put reference */
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gmap_put(gmap);
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}
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EXPORT_SYMBOL_GPL(gmap_remove);
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/**
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* gmap_enable - switch primary space to the guest address space
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