KVM: Limit vcpu mmap size to one page on non-x86

The second page is only needed on archs that support pio.

Noted by Carsten Otte.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 121e65cccc58..7972e3aa2cae 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1061,7 +1061,10 @@ static long kvm_dev_ioctl(struct file *filp,
                 r = -EINVAL;
                 if (arg)
                         goto out;
-                r = 2 * PAGE_SIZE;
+                r = PAGE_SIZE;     /* struct kvm_run */
+#ifdef CONFIG_X86
+                r += PAGE_SIZE;    /* pio data page */
+#endif
                 break;
         default:
                 return kvm_arch_dev_ioctl(filp, ioctl, arg);