From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsnZcv/oasRDjfbqPQFE4gkAANG7ysQqR6zeMcTG2aX/5fUWE6wYHFL0/FuhV4JzKYF3lSD ARC-Seal: i=1; a=rsa-sha256; t=1521214234; cv=none; d=google.com; s=arc-20160816; b=TzKNOUPyXPJJIlBs40asan9u9k2UVADAriIxwCvKjYw3z3QBQyTZofl9bw1k8b/LG2 2amzTeNW7xnrd/39FKJbuXjf0Ag7bB26bMTvtUfnZhbgXv66cIRhkt+KPZaxGMGxA7dr 7dxeNqOl+WCU7zO21zgM56dv1BSY+L4n11L01znRC64Ipilqd3jBq+woAj0z56ilC0/m 8M92SFPmWnV3/HcfPQBCYtxrELyvy0PVb1Dus7EBzwMb2khkjEaxmHMnWsyLv2DL/sHu VjF7hXxf8BoTMmOoFulUMMAkO0gQTpRv9pBOEPrNB7Wsc/xk530HVnAaVA8pQhcsG5Dt E0lQ== 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=k82zpL9TiMCRgluCmfd8fUZhmb34NNA883jQR/bNER4=; b=v5vyBGrIoS+VQgN3jyojWY63/N1VzHrZ2KSer/F1A5as8JfqP9din5hby9DDD1Pljx zEtCDxbx2+7Xtg3I41bpoxtoU6MUGPtXHFh78gpLL7H3p9NFDbtF8VKSmuRDga2KajXK DgV5dzKuYA0eQhKamIN2DrYK0DHL1dYTFwQ4tMQaipPfGq6QDZbFkcd/nDKFeArlJta/ 4n97Io+dw0nWziYIeykp7Z/qq7NQQuJyU1eYMSUd5KQw3J1C6q3OyHy0wmX3Bzssqo2P B9Ui17CjuRh2xKCOnw8+H/nuk2Mvc48hmRSAbwGMEADFdh5iLS+5saYf0DYLrIqNcgkM netg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 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 90.92.61.202 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 4.9 23/86] KVM: s390: fix memory overwrites when not using SCA entries Date: Fri, 16 Mar 2018 16:22:46 +0100 Message-Id: <20180316152318.939963790@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180316152317.167709497@linuxfoundation.org> References: <20180316152317.167709497@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?1595108737027492904?= X-GMAIL-MSGID: =?utf-8?q?1595108737027492904?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-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 @@ -1601,6 +1601,7 @@ 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) {