From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Mon, 7 Dec 2015 13:43:18 +0000 (-0500)
Subject: 4.1-stable patches
X-Git-Tag: v3.10.94~9
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=43fd9eb5344fa93b572701cda85b437a3b418dd6;p=thirdparty%2Fkernel%2Fstable-queue.git

4.1-stable patches

added patches:
	kvm-s390-enable-simd-only-when-no-vcpus-were-created.patch
---

diff --git a/queue-4.1/kvm-s390-enable-simd-only-when-no-vcpus-were-created.patch b/queue-4.1/kvm-s390-enable-simd-only-when-no-vcpus-were-created.patch
new file mode 100644
index 00000000000..0184c61fd68
--- /dev/null
+++ b/queue-4.1/kvm-s390-enable-simd-only-when-no-vcpus-were-created.patch
@@ -0,0 +1,47 @@
+From 5967c17b118a2bd1dd1d554cc4eee16233e52bec Mon Sep 17 00:00:00 2001
+From: David Hildenbrand <dahi@linux.vnet.ibm.com>
+Date: Fri, 6 Nov 2015 12:08:48 +0100
+Subject: KVM: s390: enable SIMD only when no VCPUs were created
+
+From: David Hildenbrand <dahi@linux.vnet.ibm.com>
+
+commit 5967c17b118a2bd1dd1d554cc4eee16233e52bec upstream.
+
+We should never allow to enable/disable any facilities for the guest
+when other VCPUs were already created.
+
+kvm_arch_vcpu_(load|put) relies on SIMD not changing during runtime.
+If somebody would create and run VCPUs and then decides to enable
+SIMD, undefined behaviour could be possible (e.g. vector save area
+not being set up).
+
+Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
+Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
+Signed-off-by: David Hildenbrand <dahi@linux.vnet.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 |    6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+--- a/arch/s390/kvm/kvm-s390.c
++++ b/arch/s390/kvm/kvm-s390.c
+@@ -283,12 +283,16 @@ static int kvm_vm_ioctl_enable_cap(struc
+ 		r = 0;
+ 		break;
+ 	case KVM_CAP_S390_VECTOR_REGISTERS:
+-		if (MACHINE_HAS_VX) {
++		mutex_lock(&kvm->lock);
++		if (atomic_read(&kvm->online_vcpus)) {
++			r = -EBUSY;
++		} else if (MACHINE_HAS_VX) {
+ 			set_kvm_facility(kvm->arch.model.fac->mask, 129);
+ 			set_kvm_facility(kvm->arch.model.fac->list, 129);
+ 			r = 0;
+ 		} else
+ 			r = -EINVAL;
++		mutex_unlock(&kvm->lock);
+ 		break;
+ 	case KVM_CAP_S390_USER_STSI:
+ 		kvm->arch.user_stsi = 1;
diff --git a/queue-4.1/series b/queue-4.1/series
index 8540719a573..d470b85bded 100644
--- a/queue-4.1/series
+++ b/queue-4.1/series
@@ -92,3 +92,4 @@ tty-audit-fix-audit-source.patch
 tty-fix-tty_send_xchar-lock-order-inversion.patch
 xhci-workaround-to-get-intel-xhci-reset-working-more-reliably.patch
 staging-lustre-use-jiffies-for-lp_last_query-times.patch
+kvm-s390-enable-simd-only-when-no-vcpus-were-created.patch