KVM: Remove user_alloc from struct kvm_memory_slot
Takuya Yoshikawa [Thu, 7 Feb 2013 09:55:57 +0000 (18:55 +0900)]
This field was needed to differentiate memory slots created by the new
API, KVM_SET_USER_MEMORY_REGION, from those by the old equivalent,
KVM_SET_MEMORY_REGION, whose support was dropped long before:

  commit b74a07beed0e64bfba413dcb70dd6749c57f43dc
  KVM: Remove kernel-allocated memory regions

Although we also have private memory slots to which KVM allocates
memory with vm_mmap(), !user_alloc slots in other words, the slot id
should be enough for differentiating them.

Note: corresponding function parameters will be removed later.

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

arch/x86/kvm/x86.c
include/linux/kvm_host.h
virt/kvm/kvm_main.c

index 373e17a..3c5bb6f 100644 (file)
@@ -6897,33 +6897,28 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                bool user_alloc)
 {
        int npages = memslot->npages;
-       int map_flags = MAP_PRIVATE | MAP_ANONYMOUS;
 
-       /* Prevent internal slot pages from being moved by fork()/COW. */
-       if (memslot->id >= KVM_USER_MEM_SLOTS)
-               map_flags = MAP_SHARED | MAP_ANONYMOUS;
-
-       /*To keep backward compatibility with older userspace,
-        *x86 needs to handle !user_alloc case.
+       /*
+        * Only private memory slots need to be mapped here since
+        * KVM_SET_MEMORY_REGION ioctl is no longer supported.
         */
-       if (!user_alloc) {
-               if (npages && !old.npages) {
-                       unsigned long userspace_addr;
+       if ((memslot->id >= KVM_USER_MEM_SLOTS) && npages && !old.npages) {
+               unsigned long userspace_addr;
 
-                       userspace_addr = vm_mmap(NULL, 0,
-                                                npages * PAGE_SIZE,
-                                                PROT_READ | PROT_WRITE,
-                                                map_flags,
-                                                0);
+               /*
+                * MAP_SHARED to prevent internal slot pages from being moved
+                * by fork()/COW.
+                */
+               userspace_addr = vm_mmap(NULL, 0, npages * PAGE_SIZE,
+                                        PROT_READ | PROT_WRITE,
+                                        MAP_SHARED | MAP_ANONYMOUS, 0);
 
-                       if (IS_ERR((void *)userspace_addr))
-                               return PTR_ERR((void *)userspace_addr);
+               if (IS_ERR((void *)userspace_addr))
+                       return PTR_ERR((void *)userspace_addr);
 
-                       memslot->userspace_addr = userspace_addr;
-               }
+               memslot->userspace_addr = userspace_addr;
        }
 
-
        return 0;
 }
 
@@ -6935,7 +6930,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 
        int nr_mmu_pages = 0, npages = mem->memory_size >> PAGE_SHIFT;
 
-       if (!user_alloc && !old.user_alloc && old.npages && !npages) {
+       if ((mem->slot >= KVM_USER_MEM_SLOTS) && old.npages && !npages) {
                int ret;
 
                ret = vm_munmap(old.userspace_addr,
index 0350e0d..722cae7 100644 (file)
@@ -273,7 +273,6 @@ struct kvm_memory_slot {
        unsigned long userspace_addr;
        u32 flags;
        short id;
-       bool user_alloc;
 };
 
 static inline unsigned long kvm_dirty_bitmap_bytes(struct kvm_memory_slot *memslot)
index 2e93630..adc68fe 100644 (file)
@@ -839,7 +839,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
        r = -ENOMEM;
        if (change == KVM_MR_CREATE) {
-               new.user_alloc = user_alloc;
                new.userspace_addr = mem->userspace_addr;
 
                if (kvm_arch_create_memslot(&new, npages))