KVM: Portability: Split kvm_set_memory_region() to have an arch callout

Moving !user_alloc case to kvm_arch to avoid unnecessary
code logic in non-x86 platform.

Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

3 files changed, 60 insertions, 33 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index c2acd74389fa..49094a221f6a 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -391,6 +391,10 @@ 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,
+                                struct kvm_userspace_memory_region *mem,
+                                struct kvm_memory_slot old,
+                                int user_alloc);
 gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
 void kvm_release_page_clean(struct page *page);
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 93ecafbfb1b6..9dd6ad3c6c7b 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -291,33 +291,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
                 memset(new.rmap, 0, npages * sizeof(*new.rmap));
 
                 new.user_alloc = user_alloc;
-                if (user_alloc)
-                        new.userspace_addr = mem->userspace_addr;
-                else {
-                        down_write(&current->mm->mmap_sem);
-                        new.userspace_addr = do_mmap(NULL, 0,
-                                                     npages * PAGE_SIZE,
-                                                     PROT_READ | PROT_WRITE,
-                                                     MAP_SHARED | MAP_ANONYMOUS,
-                                                     0);
-                        up_write(&current->mm->mmap_sem);
-
-                        if (IS_ERR((void *)new.userspace_addr))
-                                goto out_free;
-                }
-        } 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");
-                }
+                new.userspace_addr = mem->userspace_addr;
         }
 
         /* Allocate page dirty bitmap if needed */
@@ -335,14 +309,12 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
         *memslot = new;
 
-        if (!kvm->n_requested_mmu_pages) {
-                unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
-                kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
+        r = kvm_arch_set_memory_region(kvm, mem, old, user_alloc);
+        if (r) {
+                *memslot = old;
+                goto out_free;
         }
 
-        kvm_mmu_slot_remove_write_access(kvm, mem->slot);
-        kvm_flush_remote_tlbs(kvm);
-
         kvm_free_physmem_slot(&old, &new);
         return 0;
 
diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index 5a54e328088d..6abb2ed1a908 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -24,6 +24,7 @@
 #include <linux/fs.h>
 #include <linux/vmalloc.h>
 #include <linux/module.h>
+#include <linux/mman.h>
 
 #include <asm/uaccess.h>
 #include <asm/msr.h>
@@ -2637,3 +2638,53 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
         kvm_free_physmem(kvm);
         kfree(kvm);
 }
+
+int kvm_arch_set_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;
+        struct kvm_memory_slot *memslot = &kvm->memslots[mem->slot];
+
+        /*To keep backward compatibility with older userspace,
+         *x86 needs to hanlde !user_alloc case.
+         */
+        if (!user_alloc) {
+                if (npages && !old.rmap) {
+                        down_write(&current->mm->mmap_sem);
+                        memslot->userspace_addr = do_mmap(NULL, 0,
+                                                     npages * PAGE_SIZE,
+                                                     PROT_READ | PROT_WRITE,
+                                                     MAP_SHARED | MAP_ANONYMOUS,
+                                                     0);
+                        up_write(&current->mm->mmap_sem);
+
+                        if (IS_ERR((void *)memslot->userspace_addr))
+                                return PTR_ERR((void *)memslot->userspace_addr);
+                } 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");
+                        }
+                }
+        }
+
+        if (!kvm->n_requested_mmu_pages) {
+                unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
+                kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
+        }
+
+        kvm_mmu_slot_remove_write_access(kvm, mem->slot);
+        kvm_flush_remote_tlbs(kvm);
+
+        return 0;
+}