From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtIjiT+CRy16PhKe69Lfw8CDdGdJmWYSgjzdE7VDHVSCM7qr2Yk8GJyp5qnu1VjAdH/kbil ARC-Seal: i=1; a=rsa-sha256; t=1520955552; cv=none; d=google.com; s=arc-20160816; b=RqT3qb2Tw0PhupkDKnatNLAlIZcreKaXkgThXJemaRMLGzak9ypmEebIzE+fqzK4sF Do9SlP5sWkJ78lizKVSBCsZsmDhfAZdhqP4cuL/ISBmQgSSN62i69SxAxYb1u8z4jTvR gGykE40i433wJ2+lV44IgvIm37JrtvfswElo2ZirgY8bmrzGgBqkTLtcpTgRnKD4/Itx 8BMEDzYX36/UtcZY19f5y8vDgL2GlsMIHZPL4ce79LmsbhounzJ5QQZYnAbSvqe/5+qy oGXRaFbde6fIWP9pNbtnkWByq+T1ZTHsZPbw3+PU1HUd/iKK26VYRbLr0UAxHXZw7y55 GONA== 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=0HMRlNgnkpS2aUFNpEYIlnpEWp+vekZ/VPqt5YZ2TJI=; b=lclXjQMFBSgzcq82jbCB9aMQes8z+IfoLZActZp35XuEOnGrS6zYmMFo30v9I6oDIP vJJ7bBlV2rsJGWKZhzo2dnNOYpfqGM+NrJqXfcOqolZHl5sO7sqqM640TRfhIhiU9hTm 9nVIZuhnLE/ChfU8VOghJqVW1t7WSquGq/ng0O0ZtAdGY1G7STGHN66OeWlXGPnHLjX2 9OGREba8RPo2875iT7QUjxRx2uFhX2D0IftfdRGXsZrXdTBVpm5PUWacQRBpET6D7q9U Uk6VpD8sbje0WHPIqmH4Fcc0JZ+1IvdS/ymH5KHIzANa7TxFaz6YGm8VzwxyJpZHDuOc 2nUA== 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 4.14 089/140] KVM: s390: fix memory overwrites when not using SCA entries Date: Tue, 13 Mar 2018 16:24:52 +0100 Message-Id: <20180313152504.116029117@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180313152458.201155692@linuxfoundation.org> References: <20180313152458.201155692@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?1594837489866149384?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-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 @@ -2119,6 +2119,7 @@ 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) {