Patch "KVM: s390: fix wrong lookup of VCPUs by array index" has been added to the 4.3-stable tree

Patch "KVM: s390: fix wrong lookup of VCPUs by array index" has been added to the 4.3-stable tree

[gregkh]

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

    KVM: s390: fix wrong lookup of VCPUs by array index

to the 4.3-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-fix-wrong-lookup-of-vcpus-by-array-index.patch
and it can be found in the queue-4.3 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 152e9f65d66f0a3891efc3869440becc0e7ff53f Mon Sep 17 00:00:00 2001
From: David Hildenbrand <dahi@linux.vnet.ibm.com>
Date: Thu, 5 Nov 2015 09:06:06 +0100
Subject: KVM: s390: fix wrong lookup of VCPUs by array index

From: David Hildenbrand <dahi@linux.vnet.ibm.com>

commit 152e9f65d66f0a3891efc3869440becc0e7ff53f upstream.

For now, VCPUs were always created sequentially with incrementing
VCPU ids. Therefore, the index in the VCPUs array matched the id.

As sequential creation might change with cpu hotplug, let's use
the correct lookup function to find a VCPU by id, not array index.

Let's also use kvm_lookup_vcpu() for validation of the sending VCPU
on external call injection.

Reviewed-by: Christian Borntraeger <borntraeger@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/interrupt.c |    3 +--
 arch/s390/kvm/sigp.c      |    8 ++------
 2 files changed, 3 insertions(+), 8 deletions(-)

--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1057,8 +1057,7 @@ static int __inject_extcall(struct kvm_v
 				   src_id, 0);
 
 	/* sending vcpu invalid */
-	if (src_id >= KVM_MAX_VCPUS ||
-	    kvm_get_vcpu(vcpu->kvm, src_id) == NULL)
+	if (kvm_get_vcpu_by_id(vcpu->kvm, src_id) == NULL)
 		return -EINVAL;
 
 	if (sclp.has_sigpif)
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -291,12 +291,8 @@ static int handle_sigp_dst(struct kvm_vc
 			   u16 cpu_addr, u32 parameter, u64 *status_reg)
 {
 	int rc;
-	struct kvm_vcpu *dst_vcpu;
+	struct kvm_vcpu *dst_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
 
-	if (cpu_addr >= KVM_MAX_VCPUS)
-		return SIGP_CC_NOT_OPERATIONAL;
-
-	dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
 	if (!dst_vcpu)
 		return SIGP_CC_NOT_OPERATIONAL;
 
@@ -478,7 +474,7 @@ int kvm_s390_handle_sigp_pei(struct kvm_
 	trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr);
 
 	if (order_code == SIGP_EXTERNAL_CALL) {
-		dest_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
+		dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
 		BUG_ON(dest_vcpu == NULL);
 
 		kvm_s390_vcpu_wakeup(dest_vcpu);


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

queue-4.3/kvm-s390-sca-must-not-cross-page-boundaries.patch
queue-4.3/kvm-s390-enable-simd-only-when-no-vcpus-were-created.patch
queue-4.3/kvm-s390-fix-wrong-lookup-of-vcpus-by-array-index.patch
queue-4.3/kvm-s390-avoid-memory-overwrites-on-emergency-signal-injection.patch