4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michael S. Tsirkin <[email protected]>

commit 0178fd7dcc4451fcb90bec5e91226586962478d2 upstream.

Returning directly whatever copy_to_user(...) or copy_from_user(...)
returns may not do the right thing if there's a pagefault:
copy_to_user/copy_from_user return the number of bytes not copied in
this case, but ioctls need to return -EFAULT instead.

Fix up kvm on mips to do
        return copy_to_user(...)) ?  -EFAULT : 0;
and
        return copy_from_user(...)) ?  -EFAULT : 0;

everywhere.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/mips/kvm/mips.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -702,7 +702,7 @@ static int kvm_mips_get_reg(struct kvm_v
        } else if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U128) {
                void __user *uaddr = (void __user *)(long)reg->addr;
 
-               return copy_to_user(uaddr, vs, 16);
+               return copy_to_user(uaddr, vs, 16) ? -EFAULT : 0;
        } else {
                return -EINVAL;
        }
@@ -732,7 +732,7 @@ static int kvm_mips_set_reg(struct kvm_v
        } else if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U128) {
                void __user *uaddr = (void __user *)(long)reg->addr;
 
-               return copy_from_user(vs, uaddr, 16);
+               return copy_from_user(vs, uaddr, 16) ? -EFAULT : 0;
        } else {
                return -EINVAL;
        }


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