Patch "mips/kvm: fix ioctl error handling" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

mips/kvm: fix ioctl error handling

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mips-kvm-fix-ioctl-error-handling.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "Michael S. Tsirkin" <[email protected]>
Date: Sun, 28 Feb 2016 17:35:59 +0200
Subject: mips/kvm: fix ioctl error handling

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.

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

@@ -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;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/vfio-fix-ioctl-error-handling.patch queue-4.4/arm-arm64-kvm-fix-ioctl-error-handling.patch queue-4.4/mips-kvm-fix-ioctl-error-handling.patch