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| author | David Hildenbrand <david@redhat.com> | 2018-03-06 14:27:58 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-15 10:54:32 +0100 |
| commit | 3da2a62a61d1d228228894b16021e85cccdbe173 (patch) | |
| tree | b17118307a7a447bf7f22b311d0d885c9a1f5d12 | |
| parent | 583cc79b7380178b924f9a85a23272de2cbd5c6f (diff) | |
| download | linux-stable-3da2a62a61d1d228228894b16021e85cccdbe173.tar.gz linux-stable-3da2a62a61d1d228228894b16021e85cccdbe173.tar.bz2 linux-stable-3da2a62a61d1d228228894b16021e85cccdbe173.zip | |
KVM: s390: fix memory overwrites when not using SCA entries
commit f07afa0462b76a5b9c4f3a43d5ac24fdb86a90c2 upstream.
Even if we don't have extended SCA support, we can have more than 64 CPUs
if we don't enable any HW features that might use the SCA entries.
Now, this works just fine, but we missed a return, which is why we
would actually store the SCA entries. If we have more than 64 CPUs, this
means writing outside of the basic SCA - bad.
Let's fix this. This allows > 64 CPUs when running nested (under vSIE)
without random crashes.
Fixes: a6940674c384 ("KVM: s390: allow 255 VCPUs when sca entries aren't used")
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180306132758.21034-1-david@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f4f12ecd0cec..0fa3a788dd20 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2119,6 +2119,7 @@ static void sca_add_vcpu(struct kvm_vcpu *vcpu) /* we still need the basic sca for the ipte control */ vcpu->arch.sie_block->scaoh = (__u32)(((__u64)sca) >> 32); vcpu->arch.sie_block->scaol = (__u32)(__u64)sca; + return; } read_lock(&vcpu->kvm->arch.sca_lock); if (vcpu->kvm->arch.use_esca) { |