From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from aserp2130.oracle.com ([141.146.126.79]) by Galois.linutronix.de with esmtps (TLS1.2:RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fJsAh-0004Ee-BO for speck@linutronix.de; Sat, 19 May 2018 05:04:41 +0200 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w4J3401E003747 for ; Sat, 19 May 2018 03:04:31 GMT Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2130.oracle.com with ESMTP id 2j29ey87er-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Sat, 19 May 2018 03:04:31 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w4J34Umf004628 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Sat, 19 May 2018 03:04:30 GMT Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w4J34Uwo020114 for ; Sat, 19 May 2018 03:04:30 GMT Date: Fri, 18 May 2018 23:04:29 -0400 From: Konrad Rzeszutek Wilk Subject: [MODERATED] [boris.ostrovsky@oracle.com: Re: [speck@linutronix.de: Re: [PATCH v17.1 2/2] [PATCH v17.1 2/2] SSB Fix #2]] Message-ID: <20180519030429.GB19811@char.us.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: speck@linutronix.de List-ID: [Forwarding and encrypting.] ----- Forwarded message from Boris Ostrovsky ----- Date: Fri, 18 May 2018 17:43:26 -0400 From: Boris Ostrovsky To: Konrad Rzeszutek Wilk Subject: Re: [speck@linutronix.de: Re: [PATCH v17.1 2/2] [PATCH v17.1 2/2] SSB Fix #2] User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 On 05/18/2018 05:37 PM, Boris Ostrovsky wrote: > On 05/18/2018 05:28 PM, Konrad Rzeszutek Wilk wrote: >> Prior to that. >> >> ----- Forwarded message from speck for Konrad Rzeszutek Wilk ----- >> >> >> On Fri, May 18, 2018 at 01:40:39PM -0700, speck for Linus Torvalds wrote: >>> On Fri, 18 May 2018, speck for Konrad Rzeszutek Wilk wrote: >>>> Yup. B/c there is no early callback installed yet and it ends up using 'cli' >>> Why isn't the default callback for cli (and restore-flags) just a no-op? >> The paravirt code hadn't yet run. >>> Interrupts had better not be enabled before the callbacks are done, so >>> they *should* default to not doing anything. >>> >>> Linus >> ----- End forwarded message ----- > Here is the thing: yes, the patch is trying to work around a particular > issue with cli. But even if cli was a nop we *can't* printk() at this > point anyway! For example, I believe somewhere in bowels of printk code > there will be a dereference of a per-CPU variable. We haven't set up > per-CPU segments either. > > The point of that patch, really, is that we shouldn't be calling non-Xen > code yet. An equivalent of what xen_start_kernel() is currently doing is calling get_cpu_cap() from arch/x86/kernel/head_64.S:startup_64. -boris ----- End forwarded message -----