From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: speck@linutronix.de
Subject: [MODERATED] [boris.ostrovsky@oracle.com: Re: [speck@linutronix.de: Re: [PATCH v17.1 2/2] [PATCH v17.1 2/2] SSB Fix #2]]
Date: Fri, 18 May 2018 23:04:29 -0400 [thread overview]
Message-ID: <20180519030429.GB19811@char.us.oracle.com> (raw)
[Forwarding and encrypting.]
----- Forwarded message from Boris Ostrovsky <boris.ostrovsky@oracle.com> -----
Date: Fri, 18 May 2018 17:43:26 -0400
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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 <speck@linutronix.de> -----
>>
>>
>> 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 -----
next reply other threads:[~2018-05-19 3:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-19 3:04 Konrad Rzeszutek Wilk [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-05-19 22:03 [MODERATED] [boris.ostrovsky@oracle.com: Re: [speck@linutronix.de: Re: [PATCH v17.1 2/2] [PATCH v17.1 2/2] SSB Fix #2]] Konrad Rzeszutek Wilk
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