KVM: ensure that memslot userspace addresses are page-aligned

Bad page translation and silent guest failure ensue if the userspace address is
not page-aligned.  I hit this problem using large (host) pages with qemu,
because qemu currently has a hardcoded 4096-byte alignment for guest memory
allocations.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a65baa9039d5..0a0a9595ba3b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -715,6 +715,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
                 goto out;
         if (mem->guest_phys_addr & (PAGE_SIZE - 1))
                 goto out;
+        if (mem->userspace_addr & (PAGE_SIZE - 1))
+                goto out;
         if (mem->slot >= KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)
                 goto out;
         if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)