[PATCH 4.4 04/36] KVM: s390: Disable dirty log retrieval for UCONTROL guests

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.4 04/36] KVM: s390: Disable dirty log retrieval for UCONTROL guests
Date	2017-03-13 10:20 +0100
Message-ID	<tkuj1-6OF-49@gated-at.bofh.it> (permalink)
References	<tktPX-6ks-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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

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

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
@@ -295,6 +295,9 @@ 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;

Thread

[PATCH 4.4 00/36] 4.4.54-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 09:50 +0100
  [PATCH 4.4 18/36] ktest: Fix child exit code processing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 09:50 +0100
  [PATCH 4.4 11/36] s390: use correct input data address for setup_randomness Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 09:50 +0100
  [PATCH 4.4 27/36] drm/ast: Call open_key before enable_mmio in POST code Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 09:50 +0100
  [PATCH 4.4 05/36] KVM: VMX: use correct vmcs_read/write for guest segment selector/base Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 09:50 +0100
  [PATCH 4.4 31/36] drm/atomic: fix an error code in mode_fixup() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 35/36] fat: fix using uninitialized fields of fat_inode/fsinfo_inode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 08/36] s390/dcssblk: fix device size calculation in dcssblk_direct_access() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 07/36] s390/qdio: clear DSCI prior to scanning multiple input queues Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 04/36] KVM: s390: Disable dirty log retrieval for UCONTROL guests Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 36/36] drivers: hv: Turn off write permission on the hypercall page Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 34/36] libceph: use BUG() instead of BUG_ON(1) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:20 +0100
  [PATCH 4.4 23/36] xtensa: move parse_tag_fdt out of #ifdef CONFIG_BLK_DEV_INITRD Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 22/36] pwm: pca9685: Fix period change with same duty cycle Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 19/36] ceph: remove req from unsafe list when unregistering it Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 26/36] drm/ast: Fix test for VGA enabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 17/36] IB/srp: Fix race conditions related to task management Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 15/36] IB/IPoIB: Add destination address when re-queue packet Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 32/36] fakelb: fix schedule while atomic Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 21/36] nlm: Ensure callback code also checks that the files match Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 13/36] mnt: Tuck mounts under others instead of creating shadow/side mounts. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 20/36] target: Fix NULL dereference during LUN lookup + active I/O shutdown Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 24/36] mac80211: flush delayed work when entering suspend Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 12/36] net: mvpp2: fix DMA address calculation in mvpp2_txq_inc_put() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  [PATCH 4.4 10/36] s390: make setup_randomness work Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-13 10:30 +0100
  Re: [PATCH 4.4 00/36] 4.4.54-stable review Guenter Roeck <linux@roeck-us.net> - 2017-03-13 23:40 +0100

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