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>

1 files changed, 51 insertions, 0 deletions

diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index 5a54e328088..6abb2ed1a90 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;
+}