KVM: split kvm_arch_set_memory_region into prepare and commit

Required for SRCU convertion later.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

6 files changed, 82 insertions, 47 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 1ca1dbf48117..0757c7027986 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1578,15 +1578,15 @@ out:
         return r;
 }
 
-int kvm_arch_set_memory_region(struct kvm *kvm,
-                struct kvm_userspace_memory_region *mem,
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+                struct kvm_memory_slot *memslot,
                 struct kvm_memory_slot old,
+                struct kvm_userspace_memory_region *mem,
                 int user_alloc)
 {
         unsigned long i;
         unsigned long pfn;
-        int npages = mem->memory_size >> PAGE_SHIFT;
-        struct kvm_memory_slot *memslot = &kvm->memslots[mem->slot];
+        int npages = memslot->npages;
         unsigned long base_gfn = memslot->base_gfn;
 
         if (base_gfn + npages > (KVM_MAX_MEM_SIZE >> PAGE_SHIFT))
@@ -1610,6 +1610,14 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         return 0;
 }
 
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+                struct kvm_userspace_memory_region *mem,
+                struct kvm_memory_slot old,
+                int user_alloc)
+{
+        return;
+}
+
 void kvm_arch_flush_shadow(struct kvm *kvm)
 {
         kvm_flush_remote_tlbs(kvm);
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index f06cf93b178e..4633e7850dd2 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -165,14 +165,24 @@ long kvm_arch_dev_ioctl(struct file *filp,
         return -EINVAL;
 }
 
-int kvm_arch_set_memory_region(struct kvm *kvm,
-                               struct kvm_userspace_memory_region *mem,
-                               struct kvm_memory_slot old,
-                               int user_alloc)
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+                                   struct kvm_memory_slot *memslot,
+                                   struct kvm_memory_slot old,
+                                   struct kvm_userspace_memory_region *mem,
+                                   int user_alloc)
 {
         return 0;
 }
 
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+               struct kvm_userspace_memory_region *mem,
+               struct kvm_memory_slot old,
+               int user_alloc)
+{
+       return;
+}
+
+
 void kvm_arch_flush_shadow(struct kvm *kvm)
 {
 }
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 3fa0a10e4668..c8002193d9d4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -690,14 +690,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 }
 
 /* Section: memory related */
-int kvm_arch_set_memory_region(struct kvm *kvm,
-                                struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old,
-                                int user_alloc)
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+                                   struct kvm_memory_slot *memslot,
+                                   struct kvm_memory_slot old,
+                                   struct kvm_userspace_memory_region *mem,
+                                   int user_alloc)
 {
-        int i;
-        struct kvm_vcpu *vcpu;
-
         /* A few sanity checks. We can have exactly one memory slot which has
            to start at guest virtual zero and which has to be located at a
            page boundary in userland and which has to end at a page boundary.
@@ -720,14 +718,23 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         if (!user_alloc)
                 return -EINVAL;
 
+        return 0;
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+                                struct kvm_userspace_memory_region *mem,
+                                struct kvm_memory_slot old,
+                                int user_alloc)
+{
+        int i;
+        struct kvm_vcpu *vcpu;
+
         /* request update of sie control block for all available vcpus */
         kvm_for_each_vcpu(i, vcpu, kvm) {
                 if (test_and_set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
                         continue;
                 kvm_s390_inject_sigp_stop(vcpu, ACTION_RELOADVCPU_ON_STOP);
         }
-
-        return 0;
 }
 
 void kvm_arch_flush_shadow(struct kvm *kvm)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1ce833191430..43da65feed49 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5228,13 +5228,13 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
         kfree(kvm);
 }
 
-int kvm_arch_set_memory_region(struct kvm *kvm,
-                                struct kvm_userspace_memory_region *mem,
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+                                struct kvm_memory_slot *memslot,
                                 struct kvm_memory_slot old,
+                                struct kvm_userspace_memory_region *mem,
                                 int user_alloc)
 {
-        int npages = mem->memory_size >> PAGE_SHIFT;
-        struct kvm_memory_slot *memslot = &kvm->memslots->memslots[mem->slot];
+        int npages = memslot->npages;
 
         /*To keep backward compatibility with older userspace,
          *x86 needs to hanlde !user_alloc case.
@@ -5254,26 +5254,35 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                         if (IS_ERR((void *)userspace_addr))
                                 return PTR_ERR((void *)userspace_addr);
 
-                        /* set userspace_addr atomically for kvm_hva_to_rmapp */
-                        spin_lock(&kvm->mmu_lock);
                         memslot->userspace_addr = userspace_addr;
-                        spin_unlock(&kvm->mmu_lock);
-                } else {
-                        if (!old.user_alloc && old.rmap) {
-                                int ret;
-
-                                down_write(&current->mm->mmap_sem);
-                                ret = do_munmap(current->mm, old.userspace_addr,
-                                                old.npages * PAGE_SIZE);
-                                up_write(&current->mm->mmap_sem);
-                                if (ret < 0)
-                                        printk(KERN_WARNING
-                                       "kvm_vm_ioctl_set_memory_region: "
-                                       "failed to munmap memory\n");
-                        }
                 }
         }
 
+
+        return 0;
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+                                struct kvm_userspace_memory_region *mem,
+                                struct kvm_memory_slot old,
+                                int user_alloc)
+{
+
+        int npages = mem->memory_size >> PAGE_SHIFT;
+
+        if (!user_alloc && !old.user_alloc && old.rmap && !npages) {
+                int ret;
+
+                down_write(&current->mm->mmap_sem);
+                ret = do_munmap(current->mm, old.userspace_addr,
+                                old.npages * PAGE_SIZE);
+                up_write(&current->mm->mmap_sem);
+                if (ret < 0)
+                        printk(KERN_WARNING
+                               "kvm_vm_ioctl_set_memory_region: "
+                               "failed to munmap memory\n");
+        }
+
         spin_lock(&kvm->mmu_lock);
         if (!kvm->arch.n_requested_mmu_pages) {
                 unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
@@ -5282,8 +5291,6 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
 
         kvm_mmu_slot_remove_write_access(kvm, mem->slot);
         spin_unlock(&kvm->mmu_lock);
-
-        return 0;
 }
 
 void kvm_arch_flush_shadow(struct kvm *kvm)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 782bfb185f8a..3c44687b3425 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -253,7 +253,12 @@ int kvm_set_memory_region(struct kvm *kvm,
 int __kvm_set_memory_region(struct kvm *kvm,
                             struct kvm_userspace_memory_region *mem,
                             int user_alloc);
-int kvm_arch_set_memory_region(struct kvm *kvm,
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+                                struct kvm_memory_slot *memslot,
+                                struct kvm_memory_slot old,
+                                struct kvm_userspace_memory_region *mem,
+                                int user_alloc);
+void kvm_arch_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
                                 struct kvm_memory_slot old,
                                 int user_alloc);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 86dd8f3d29c9..c9f6cfe83120 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -663,6 +663,10 @@ skip_lpage:
         if (!npages)
                 kvm_arch_flush_shadow(kvm);
 
+        r = kvm_arch_prepare_memory_region(kvm, &new, old, mem, user_alloc);
+        if (r)
+                goto out_free;
+
         spin_lock(&kvm->mmu_lock);
         if (mem->slot >= kvm->memslots->nmemslots)
                 kvm->memslots->nmemslots = mem->slot + 1;
@@ -670,13 +674,7 @@ skip_lpage:
         *memslot = new;
         spin_unlock(&kvm->mmu_lock);
 
-        r = kvm_arch_set_memory_region(kvm, mem, old, user_alloc);
-        if (r) {
-                spin_lock(&kvm->mmu_lock);
-                *memslot = old;
-                spin_unlock(&kvm->mmu_lock);
-                goto out_free;
-        }
+        kvm_arch_commit_memory_region(kvm, mem, old, user_alloc);
 
         kvm_free_physmem_slot(&old, npages ? &new : NULL);
         /* Slot deletion case: we have to update the current slot */