From: Paolo Bonzini <pbonzini@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kvm list <kvm@vger.kernel.org>, Andy Lutomirski <luto@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Rik van Riel <riel@redhat.com>,
Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH 3/3] x86: context_tracking: avoid irq_save/irq_restore on kernel entry and exit
Date: Tue, 15 Mar 2016 09:51:49 +0100 [thread overview]
Message-ID: <56E7CD25.8070507@redhat.com> (raw)
In-Reply-To: <CALCETrWfKedMX16=QXiwM5_VxdU9MYpgTgPKUf_5A_bnnt+w9g@mail.gmail.com>
On 14/03/2016 20:23, Andy Lutomirski wrote:
> On Tue, Oct 27, 2015 at 10:22 PM, Andy Lutomirski <luto@amacapital.net> wrote:
>> On Tue, Oct 27, 2015 at 6:39 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>> x86 always calls user_enter and user_exit with interrupt disabled.
>>> Therefore, it is not necessary to check for exceptions, nor to
>>> save/restore the IRQ state, when context tracking functions are
>>> called by guest_enter and guest_exit.
>>>
>>> Use the previously introduced __context_tracking_entry and
>>> __context_tracking_exit.
>>
>> x86 isn't ready for this yet. We could do a quick-and-dirty fix with
>> explicit IRQs-on-and-off much protected by the static key, or we could
>> just wait until I finish the syscall cleanup. I favor the latter, but
>> you're all welcome to do the former and I'll review it.
>>
>
> Once Linus pulls tip:x86/asm, x86 should be ready for this. Want to try again?
Yup, it's on my todo list. :)
Paolo
next prev parent reply other threads:[~2016-03-15 8:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-28 1:39 [PATCH 0/3] context_tracking: streamline code, avoid IRQ save/restore Paolo Bonzini
2015-10-28 1:39 ` [PATCH 1/3] context_tracking: remove duplicate enabled check Paolo Bonzini
2015-10-28 5:19 ` Andy Lutomirski
2015-11-07 9:38 ` Paolo Bonzini
2015-11-09 13:57 ` Rik van Riel
2015-10-28 1:39 ` [PATCH 2/3] context_tracking: avoid irq_save/irq_restore on guest entry and exit Paolo Bonzini
2015-10-28 5:20 ` Andy Lutomirski
2015-11-09 13:58 ` Rik van Riel
2015-10-28 1:39 ` [PATCH 3/3] x86: context_tracking: avoid irq_save/irq_restore on kernel " Paolo Bonzini
2015-10-28 5:22 ` Andy Lutomirski
2015-10-28 14:51 ` Paolo Bonzini
2016-03-14 19:23 ` Andy Lutomirski
2016-03-15 8:51 ` Paolo Bonzini [this message]
2015-10-28 2:05 ` [PATCH 0/3] context_tracking: streamline code, avoid IRQ save/restore Paolo Bonzini
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