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Subject: Re: [PATCH] x86/paravirt: Drop {read,write}_cr8() hooks
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Stephane Eranian <eranian@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        FengTang <feng.tang@intel.com>, X86 ML <x86@kernel.org>,
        Linux Virtualization <virtualization@lists.linux-foundation.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        "Rafael J.Wysocki" <rjw@rjwysocki.net>,
        Pavel Machek <pavel@ucw.cz>,
        LKML <linux-kernel@vger.kernel.org>,
        Alok Kataria <akataria@vmware.com>,
        Nadav Amit <namit@vmware.com>
References: <20190715130056.10627-1-andrew.cooper3@citrix.com>
 <a04918d1-975e-5869-1ecd-c9df4ae5b1c1@suse.com>
 <CALCETrX0T=vzyN8gqoBmA72xwzS45d5bDTfcZQJayht9n9ijPA@mail.gmail.com>
From:   Juergen Gross <jgross@suse.com>
Message-ID: <f51ce980-599b-cae3-e3fa-4a67443ea128@suse.com>
Date:   Mon, 15 Jul 2019 16:52:11 +0200
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On 15.07.19 16:26, Andy Lutomirski wrote:
> On Mon, Jul 15, 2019 at 6:23 AM Juergen Gross <jgross@suse.com> wrote:
>>
>> On 15.07.19 15:00, Andrew Cooper wrote:
>>> There is a lot of infrastructure for functionality which is used
>>> exclusively in __{save,restore}_processor_state() on the suspend/resume
>>> path.
>>>
>>> cr8 is an alias of APIC_TASKPRI, and APIC_TASKPRI is saved/restored
>>> independently by lapic_{suspend,resume}().
>>
>> Aren't those called only with CONFIG_PM set?
>>
> 
> 
> Unless I'm missing something, we only build any of the restore code
> (including the write_cr8() call) if CONFIG_PM_SLEEP is set, and that
> selects CONFIG_PM, so we should be fine, I think.
> 

Okay, in that case I'd suggest to remove "cr8" from struct saved_context
as it won't be used any longer.


Juergen