From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtvU8o6XIg/AeqQfrnta1TZ+Z8Iu1k65nEQxLCEgUnw67vKhpLzBC2I0NJDLC2YOWmYaYdP ARC-Seal: i=1; a=rsa-sha256; t=1520954993; cv=none; d=google.com; s=arc-20160816; b=G7jyESGBzEUw+tPoNN+eR7KU1MswCmAnoO/msk+uKCxo5a5+V56e05hoJalIW2hQyj qzrqBxigVV6qb242GyQPK4hnWmZGSgSp9UvN/P6H4s/vTHs9w1RkcBgvR4uBg8SH7tBa gIZ2b5etc+dgc9m5EF1sbyfgv/hRPBElH+tNmp/mslaP7/oAK+NRKi0TVPbfkQCwgtoC yQ3ApGMgPJN2bbJM3YX9tYnLGaWsxNZUH4WR2GTrYyPwUkZp7oHGb7vJsCCIcVj8vAHM 89lDjk4XBIq88zRlFhlNY/Qj/ZBLAorIYrm+JBPT8uENvoTQAA5GrdHmWIK0Vq3HVO3g FR+A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=gjE0g4KPD8S22Y9gMWeel5XM5l+6Om1tyahMvELWnoc=; b=jsNtp9A0GWk+ZalZCgqcIai/PL/aMA6nJuaC3JejK0SI8XBccSOzfUV+dv6tvNm9mP ImpsxAl39ZcyUYu41Rt8BrhYXkTMYaCNEBzH5LDqykbwXRUCvZPQ44GUx5yQDeTT+al7 5slia16Br+JCwppNMBnvdnHjy0PITgefc+RyHW+dhpkoWbgzqQ4Iqt7xnrUnW6Qs8tuN DmiiRw9Clm7mBf8FQN9YmJrclazhrYrC307UrwxEZbip9L1wn54WdhNTQpOEl/udsvYZ KLr+h8VMSIoKGjff5ip4F7O677D9pMc4NwXOmRW7CIHdvg2RX6fX9v9g28LOIud9Gbtp YmnA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christian Borntraeger , David Hildenbrand , Cornelia Huck Subject: [PATCH 4.15 053/146] KVM: s390: fix memory overwrites when not using SCA entries Date: Tue, 13 Mar 2018 16:23:40 +0100 Message-Id: <20180313152324.733971401@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180313152320.439085687@linuxfoundation.org> References: <20180313152320.439085687@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1594836903307298402?= X-GMAIL-MSGID: =?utf-8?q?1594836903307298402?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Hildenbrand 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 Tested-by: Christian Borntraeger Signed-off-by: David Hildenbrand Message-Id: <20180306132758.21034-1-david@redhat.com> Cc: stable@vger.kernel.org Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman --- arch/s390/kvm/kvm-s390.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2118,6 +2118,7 @@ static void sca_add_vcpu(struct kvm_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) {