From: Ingo Molnar <mingo@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-arch <linux-arch@vger.kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
Andi Kleen <ak@linux.intel.com>,
Kees Cook <keescook@chromium.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Greg KH <gregkh@linuxfoundation.org>, X86 ML <x86@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>,
"H. Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alan Cox <alan@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 04/12] x86: introduce __uaccess_begin_nospec and ifence
Date: Tue, 30 Jan 2018 07:56:53 +0100 [thread overview]
Message-ID: <20180130065653.gsp7blb3jttd6e6t@gmail.com> (raw)
In-Reply-To: <CAPcyv4hmkJyFgCBCXR8A1ykzk1tsxX-Lg4qgimhGxne=iG1Hzg@mail.gmail.com>
* Dan Williams <dan.j.williams@intel.com> wrote:
> > The flip side is that if the MFENCE stalls the STAC that is ahead of it could be
> > processed for 'free' - while it's always post barrier with my suggestion.
>
> This 'for free' aspect is what I aiming for.
Ok.
> >
> > But in any case it would be nice to see a discussion of this aspect in the
> > changelog, even if the patch does not change.
>
> I'll add a note to the changelog that having the fence after the
> 'stac' hopefully allows some overlap of the cost of 'stac' and the
> flushing of the instruction pipeline.
Perfect!
Thanks,
Ingo
next prev parent reply other threads:[~2018-01-30 6:56 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-27 7:55 [kernel-hardening] [PATCH v5 00/12] spectre variant1 mitigations for tip/x86/pti Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 01/12] Documentation: document array_idx Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 02/12] array_idx: sanitize speculative array de-references Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 8:55 ` [kernel-hardening] " Ingo Molnar
2018-01-28 8:55 ` Ingo Molnar
2018-01-28 11:36 ` [kernel-hardening] " Thomas Gleixner
2018-01-28 11:36 ` Thomas Gleixner
2018-01-28 16:28 ` [kernel-hardening] " Dan Williams
2018-01-28 16:28 ` Dan Williams
2018-01-28 18:33 ` [kernel-hardening] " Ingo Molnar
2018-01-28 18:33 ` Ingo Molnar
2018-01-29 16:45 ` Dan Williams
2018-01-28 18:36 ` [kernel-hardening] " Thomas Gleixner
2018-01-28 18:36 ` Thomas Gleixner
2018-01-30 6:29 ` Dan Williams
2018-01-30 19:38 ` Linus Torvalds
2018-01-30 20:13 ` Dan Williams
2018-01-30 20:27 ` Van De Ven, Arjan
2018-01-31 8:03 ` Ingo Molnar
2018-01-31 14:13 ` Van De Ven, Arjan
2018-01-31 14:21 ` Greg KH
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 03/12] x86: implement array_idx_mask Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 9:02 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:02 ` Ingo Molnar
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 04/12] x86: introduce __uaccess_begin_nospec and ifence Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 9:06 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:06 ` Ingo Molnar
2018-01-28 9:14 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:14 ` Ingo Molnar
2018-01-29 20:41 ` Dan Williams
2018-01-30 6:56 ` Ingo Molnar [this message]
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 05/12] x86, __get_user: use __uaccess_begin_nospec Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 9:19 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:19 ` Ingo Molnar
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 06/12] x86, get_user: use pointer masking to limit speculation Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 9:25 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:25 ` Ingo Molnar
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 07/12] x86: remove the syscall_64 fast-path Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 9:29 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:29 ` Ingo Molnar
2018-01-28 15:22 ` [kernel-hardening] " Andy Lutomirski
2018-01-28 15:22 ` Andy Lutomirski
2018-01-27 7:55 ` [kernel-hardening] [PATCH v5 08/12] x86: sanitize sycall table de-references under speculation Dan Williams
2018-01-27 7:55 ` Dan Williams
2018-01-28 9:36 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:36 ` Ingo Molnar
2018-01-27 7:56 ` [kernel-hardening] [PATCH v5 09/12] vfs, fdtable: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-27 7:56 ` Dan Williams
2018-01-27 7:56 ` [kernel-hardening] [PATCH v5 10/12] kvm, x86: update spectre-v1 mitigation Dan Williams
2018-01-27 7:56 ` Dan Williams
2018-01-27 7:56 ` [kernel-hardening] [PATCH v5 11/12] nl80211: sanitize array index in parse_txq_params Dan Williams
2018-01-27 7:56 ` Dan Williams
2018-01-27 7:56 ` Dan Williams
2018-01-27 7:56 ` [kernel-hardening] [PATCH v5 12/12] x86/spectre: report get_user mitigation for spectre_v1 Dan Williams
2018-01-27 7:56 ` Dan Williams
2018-01-28 9:50 ` [kernel-hardening] " Ingo Molnar
2018-01-28 9:50 ` Ingo Molnar
2018-01-29 22:05 ` Dan Williams
2018-01-31 8:07 ` Ingo Molnar
2018-02-01 20:23 ` Dan Williams
2018-01-27 18:52 ` [kernel-hardening] Re: [PATCH v5 00/12] spectre variant1 mitigations for tip/x86/pti Linus Torvalds
2018-01-27 18:52 ` Linus Torvalds
2018-01-27 18:52 ` Linus Torvalds
2018-01-27 19:26 ` [kernel-hardening] " Dan Williams
2018-01-27 19:26 ` Dan Williams
2018-01-27 19:26 ` Dan Williams
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