KVM: Return EFAULT from kvm ioctl when guest accesses bad area

Currently if guest access address that belongs to memory slot but is not
backed up by page or page is read only KVM treats it like MMIO access.
Remove that capability. It was never part of the interface and should
not be relied upon.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d8d48329cb82..89d7a2cae53b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2078,7 +2078,9 @@ static int kvm_handle_bad_page(struct kvm *kvm, gfn_t gfn, pfn_t pfn)
         if (is_hwpoison_pfn(pfn)) {
                 kvm_send_hwpoison_signal(kvm, gfn);
                 return 0;
-        }
+        } else if (is_fault_pfn(pfn))
+                return -EFAULT;
+
         return 1;
 }