Patch "KVM: s390: Disable dirty log retrieval for UCONTROL guests" has been added to the 4.9-stable tree

Patch "KVM: s390: Disable dirty log retrieval for UCONTROL guests" has been added to the 4.9-stable tree

[gregkh]

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

    KVM: s390: Disable dirty log retrieval for UCONTROL guests

to the 4.9-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:
     kvm-s390-disable-dirty-log-retrieval-for-ucontrol-guests.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e1e8a9624f7ba8ead4f056ff558ed070e86fa747 Mon Sep 17 00:00:00 2001
From: Janosch Frank <frankja@linux.vnet.ibm.com>
Date: Thu, 2 Feb 2017 16:39:31 +0100
Subject: KVM: s390: Disable dirty log retrieval for UCONTROL guests

From: Janosch Frank <frankja@linux.vnet.ibm.com>

commit e1e8a9624f7ba8ead4f056ff558ed070e86fa747 upstream.

User controlled KVM guests do not support the dirty log, as they have
no single gmap that we can check for changes.

As they have no single gmap, kvm->arch.gmap is NULL and all further
referencing to it for dirty checking will result in a NULL
dereference.

Let's return -EINVAL if a caller tries to sync dirty logs for a
UCONTROL guest.

Fixes: 15f36eb ("KVM: s390: Add proper dirty bitmap support to S390 kvm.")
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reported-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/s390/kvm/kvm-s390.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -442,6 +442,9 @@ int kvm_vm_ioctl_get_dirty_log(struct kv
 	struct kvm_memory_slot *memslot;
 	int is_dirty = 0;
 
+	if (kvm_is_ucontrol(kvm))
+		return -EINVAL;
+
 	mutex_lock(&kvm->slots_lock);
 
 	r = -EINVAL;


Patches currently in stable-queue which might be from frankja@linux.vnet.ibm.com are

queue-4.9/kvm-s390-disable-dirty-log-retrieval-for-ucontrol-guests.patch