KVM: Add kvm_read_guest_atomic()
In preparation for a mmu spinlock, add kvm_read_guest_atomic()
and use it in fetch() and prefetch_page().
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 678e805..8d0b7c1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -541,6 +541,26 @@
}
EXPORT_SYMBOL_GPL(kvm_read_guest);
+int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
+ unsigned long len)
+{
+ int r;
+ unsigned long addr;
+ gfn_t gfn = gpa >> PAGE_SHIFT;
+ int offset = offset_in_page(gpa);
+
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr))
+ return -EFAULT;
+ pagefault_disable();
+ r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
+ pagefault_enable();
+ if (r)
+ return -EFAULT;
+ return 0;
+}
+EXPORT_SYMBOL(kvm_read_guest_atomic);
+
int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
int offset, int len)
{