KVM: introduce id_to_memslot function

Introduce id_to_memslot to get memslot by slot id

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

6 files changed, 30 insertions, 17 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 42ad1f9c9f01..92d9f1e4740f 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1818,7 +1818,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
         if (log->slot >= KVM_MEMORY_SLOTS)
                 goto out;
 
-        memslot = &kvm->memslots->memslots[log->slot];
+        memslot = id_to_memslot(kvm->memslots, log->slot);
         r = -ENOENT;
         if (!memslot->dirty_bitmap)
                 goto out;
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index a459479995c6..e41ac6f7dcf1 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -498,7 +498,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 
         /* If nothing is dirty, don't bother messing with page tables. */
         if (is_dirty) {
-                memslot = &kvm->memslots->memslots[log->slot];
+                memslot = id_to_memslot(kvm->memslots, log->slot);
 
                 ga = memslot->base_gfn << PAGE_SHIFT;
                 ga_end = ga + (memslot->npages << PAGE_SHIFT);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ba24022f4575..8f19d91ec3e7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2711,11 +2711,13 @@ static gva_t rmode_tss_base(struct kvm *kvm)
 {
         if (!kvm->arch.tss_addr) {
                 struct kvm_memslots *slots;
+                struct kvm_memory_slot *slot;
                 gfn_t base_gfn;
 
                 slots = kvm_memslots(kvm);
-                base_gfn = slots->memslots[0].base_gfn +
-                                 kvm->memslots->memslots[0].npages - 3;
+                slot = id_to_memslot(slots, 0);
+                base_gfn = slot->base_gfn + slot->npages - 3;
+
                 return base_gfn << PAGE_SHIFT;
         }
         return kvm->arch.tss_addr;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 917a287d21c8..b6776c613e6d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3520,7 +3520,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
         if (log->slot >= KVM_MEMORY_SLOTS)
                 goto out;
 
-        memslot = &kvm->memslots->memslots[log->slot];
+        memslot = id_to_memslot(kvm->memslots, log->slot);
         r = -ENOENT;
         if (!memslot->dirty_bitmap)
                 goto out;
@@ -3531,27 +3531,27 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
         /* If nothing is dirty, don't bother messing with page tables. */
         if (nr_dirty_pages) {
                 struct kvm_memslots *slots, *old_slots;
-                unsigned long *dirty_bitmap;
+                unsigned long *dirty_bitmap, *dirty_bitmap_head;
 
-                dirty_bitmap = memslot->dirty_bitmap_head;
-                if (memslot->dirty_bitmap == dirty_bitmap)
-                        dirty_bitmap += n / sizeof(long);
-                memset(dirty_bitmap, 0, n);
+                dirty_bitmap = memslot->dirty_bitmap;
+                dirty_bitmap_head = memslot->dirty_bitmap_head;
+                if (dirty_bitmap == dirty_bitmap_head)
+                        dirty_bitmap_head += n / sizeof(long);
+                memset(dirty_bitmap_head, 0, n);
 
                 r = -ENOMEM;
                 slots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
                 if (!slots)
                         goto out;
                 memcpy(slots, kvm->memslots, sizeof(struct kvm_memslots));
-                memslot = &slots->memslots[log->slot];
-                memslot->dirty_bitmap = dirty_bitmap;
+                memslot = id_to_memslot(slots, log->slot);
                 memslot->nr_dirty_pages = 0;
+                memslot->dirty_bitmap = dirty_bitmap_head;
                 update_memslots(slots, NULL);
 
                 old_slots = kvm->memslots;
                 rcu_assign_pointer(kvm->memslots, slots);
                 synchronize_srcu_expedited(&kvm->srcu);
-                dirty_bitmap = old_slots->memslots[log->slot].dirty_bitmap;
                 kfree(old_slots);
 
                 write_protect_slot(kvm, memslot, dirty_bitmap, nr_dirty_pages);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 392af47a4353..123925cd3ae8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -333,6 +333,12 @@ static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm)
                         || lockdep_is_held(&kvm->slots_lock));
 }
 
+static inline struct kvm_memory_slot *
+id_to_memslot(struct kvm_memslots *slots, int id)
+{
+        return &slots->memslots[id];
+}
+
 #define HPA_MSB ((sizeof(hpa_t) * 8) - 1)
 #define HPA_ERR_MASK ((hpa_t)1 << HPA_MSB)
 static inline int is_error_hpa(hpa_t hpa) { return hpa >> HPA_MSB; }
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4c2900c5d81d..7b6084999424 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -634,8 +634,9 @@ void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
 {
         if (new) {
                 int id = new->id;
+                struct kvm_memory_slot *old = id_to_memslot(slots, id);
 
-                slots->memslots[id] = *new;
+                *old = *new;
                 if (id >= slots->nmemslots)
                         slots->nmemslots = id + 1;
         }
@@ -681,7 +682,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
         if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
                 goto out;
 
-        memslot = &kvm->memslots->memslots[mem->slot];
+        memslot = id_to_memslot(kvm->memslots, mem->slot);
         base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
         npages = mem->memory_size >> PAGE_SHIFT;
 
@@ -788,12 +789,16 @@ skip_lpage:
 #endif /* not defined CONFIG_S390 */
 
         if (!npages) {
+                struct kvm_memory_slot *slot;
+
                 r = -ENOMEM;
                 slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
                                 GFP_KERNEL);
                 if (!slots)
                         goto out_free;
-                slots->memslots[mem->slot].flags |= KVM_MEMSLOT_INVALID;
+                slot = id_to_memslot(slots, mem->slot);
+                slot->flags |= KVM_MEMSLOT_INVALID;
+
                 update_memslots(slots, NULL);
 
                 old_memslots = kvm->memslots;
@@ -897,7 +902,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
         if (log->slot >= KVM_MEMORY_SLOTS)
                 goto out;
 
-        memslot = &kvm->memslots->memslots[log->slot];
+        memslot = id_to_memslot(kvm->memslots, log->slot);
         r = -ENOENT;
         if (!memslot->dirty_bitmap)
                 goto out;