KVM: introduce gfn_to_hva_read/kvm_read_hva/kvm_read_hva_atomic
This set of functions is only used to read data from host space, in the
later patch, we will only get a readonly hva in gfn_to_hva_read, and
the function name is a good hint to let gfn_to_hva_read to pair with
kvm_read_hva()/kvm_read_hva_atomic()
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 543f9b7..6e3ea15 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1002,6 +1002,25 @@
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
+/*
+ * The hva returned by this function is only allowed to be read.
+ * It should pair with kvm_read_hva() or kvm_read_hva_atomic().
+ */
+static unsigned long gfn_to_hva_read(struct kvm *kvm, gfn_t gfn)
+{
+ return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
+}
+
+static int kvm_read_hva(void *data, void __user *hva, int len)
+{
+ return __copy_from_user(data, hva, len);
+}
+
+static int kvm_read_hva_atomic(void *data, void __user *hva, int len)
+{
+ return __copy_from_user_inatomic(data, hva, len);
+}
+
int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int write, struct page **page)
{
@@ -1274,10 +1293,10 @@
int r;
unsigned long addr;
- addr = gfn_to_hva(kvm, gfn);
+ addr = gfn_to_hva_read(kvm, gfn);
if (kvm_is_error_hva(addr))
return -EFAULT;
- r = __copy_from_user(data, (void __user *)addr + offset, len);
+ r = kvm_read_hva(data, (void __user *)addr + offset, len);
if (r)
return -EFAULT;
return 0;
@@ -1312,11 +1331,11 @@
gfn_t gfn = gpa >> PAGE_SHIFT;
int offset = offset_in_page(gpa);
- addr = gfn_to_hva(kvm, gfn);
+ addr = gfn_to_hva_read(kvm, gfn);
if (kvm_is_error_hva(addr))
return -EFAULT;
pagefault_disable();
- r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
+ r = kvm_read_hva_atomic(data, (void __user *)addr + offset, len);
pagefault_enable();
if (r)
return -EFAULT;