KVM: Allow kernel to select size of mmap() buffer
This allows us to store offsets in the kernel/user kvm_run area, and be
sure that userspace has them mapped. As offsets can be outside the
kvm_run struct, userspace has no way of knowing how much to mmap.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index c0d10cd..dad9081 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -253,6 +253,10 @@
* return is 1 (yes) or 0 (no, sorry).
*/
#define KVM_CHECK_EXTENSION _IO(KVMIO, 0x03)
+/*
+ * Get size for mmap(vcpu_fd)
+ */
+#define KVM_GET_VCPU_MMAP_SIZE _IO(KVMIO, 0x04) /* in bytes */
/*
* ioctls for VM fds