From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Thomas Mingarelli <thomas.mingarelli@hpe.com>,
hpa@zytor.com, tglx@linutronix.de, torvalds@linux-foundation.org,
linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
Dave Hansen <dave@sr71.net>, Borislav Petkov <bp@alien8.de>,
Arjan van de Ven <arjan@infradead.org>
Subject: Re: [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware
Date: Mon, 12 Feb 2018 14:06:40 +0100 [thread overview]
Message-ID: <20180212130640.GK25181@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1518438439.6606.36.camel@infradead.org>
On Mon, Feb 12, 2018 at 12:27:19PM +0000, David Woodhouse wrote:
> On Mon, 2018-02-12 at 12:50 +0100, Peter Zijlstra wrote:
> > Wait, we're doing firmware from NMI? That sounds like a _REALLY_ bad
> > idea.
>
> And spin_lock_irqsave() too. Which is probably why I missed the fact
> that this was being called in NMI context.
>
> Yay for HP and their persistent attempts to "value subtract" in their
> firmware offerings.
>
> I'm tempted to drop that part of the patch and declare that if you're
> using this driver, the potential for stray branch prediction when you
> call into the firmware from the NMI handler is the *least* of your
> problems.
We should probably mark it BROKEN or something, or move it into staging.
next prev parent reply other threads:[~2018-02-12 13:11 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-10 23:39 [PATCH v2 0/6] Spectre v2 updates David Woodhouse
2018-02-10 23:39 ` [PATCH v2 1/6] x86/speculation: Update Speculation Control microcode blacklist David Woodhouse
2018-02-11 12:08 ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-02-12 9:50 ` [PATCH v2 1/6] " Darren Kenny
2018-02-12 14:16 ` David Woodhouse
2018-02-12 14:32 ` Thomas Gleixner
2018-02-10 23:39 ` [PATCH v2 2/6] Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()" David Woodhouse
2018-02-11 12:09 ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-02-13 8:58 ` tip-bot for David Woodhouse
2018-02-13 9:41 ` Peter Zijlstra
2018-02-13 11:28 ` Ingo Molnar
2018-02-13 13:28 ` Peter Zijlstra
2018-02-13 13:38 ` Ingo Molnar
2018-02-13 15:26 ` [tip:x86/pti] x86/speculation: Add <asm/msr-index.h> dependency tip-bot for Peter Zijlstra
2018-02-15 0:28 ` tip-bot for Peter Zijlstra
2018-02-10 23:39 ` [PATCH v2 3/6] KVM: x86: Reduce retpoline performance impact in slot_handle_level_range() David Woodhouse
2018-02-11 12:09 ` [tip:x86/pti] KVM/x86: Reduce retpoline performance impact in slot_handle_level_range(), by always inlining iterator helper methods tip-bot for David Woodhouse
2018-02-13 8:58 ` tip-bot for David Woodhouse
2018-02-10 23:39 ` [PATCH v2 4/6] X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs David Woodhouse
2018-02-11 12:10 ` [tip:x86/pti] " tip-bot for KarimAllah Ahmed
2018-02-13 8:59 ` tip-bot for KarimAllah Ahmed
2018-02-10 23:39 ` [PATCH v2 5/6] KVM/nVMX: Set the CPU_BASED_USE_MSR_BITMAPS if we have a valid L02 MSR bitmap David Woodhouse
2018-02-11 10:19 ` Ingo Molnar
[not found] ` <1518345844.3677.365.camel@amazon.co.uk>
2018-02-11 10:55 ` Ingo Molnar
2018-02-11 12:10 ` [tip:x86/pti] " tip-bot for KarimAllah Ahmed
2018-02-13 8:59 ` tip-bot for KarimAllah Ahmed
2018-02-10 23:39 ` [PATCH v2 6/6] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-11 11:46 ` Ingo Molnar
2018-02-11 10:41 ` [PATCH v2 0/6] Spectre v2 updates Ingo Molnar
2018-02-11 15:19 ` [PATCH v2.1] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-11 18:50 ` [PATCH] x86/speculation: Clean up various Spectre related details Ingo Molnar
2018-02-11 19:25 ` David Woodhouse
2018-02-11 19:43 ` Ingo Molnar
2018-02-12 15:30 ` David Woodhouse
2018-02-13 8:04 ` Ingo Molnar
2018-02-11 19:19 ` [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware tip-bot for David Woodhouse
2018-02-12 5:59 ` afzal mohammed
2018-02-12 16:30 ` David Woodhouse
2018-02-12 10:22 ` Ingo Molnar
2018-02-12 11:50 ` Peter Zijlstra
2018-02-12 12:27 ` David Woodhouse
2018-02-12 13:06 ` Peter Zijlstra [this message]
2018-02-13 7:58 ` Ingo Molnar
2018-02-12 12:28 ` Peter Zijlstra
2018-02-12 16:13 ` Dave Hansen
2018-02-12 16:58 ` Peter Zijlstra
2018-02-13 7:55 ` Ingo Molnar
2018-02-14 1:49 ` Tim Chen
2018-02-14 8:56 ` Peter Zijlstra
2018-02-14 8:57 ` Peter Zijlstra
2018-02-14 19:20 ` Tim Chen
2018-02-14 23:19 ` Ingo Molnar
2018-02-15 2:01 ` Tim Chen
2018-02-14 9:31 ` [PATCH] watchdog: hpwdt: Remove spinlock acquire and BIOS calls from NMI context Ingo Molnar
2018-02-14 9:38 ` Peter Zijlstra
2018-02-14 10:39 ` Ingo Molnar
2018-02-14 9:44 ` Borislav Petkov
2018-02-14 18:13 ` Jerry Hoemann
2018-02-14 23:17 ` Ingo Molnar
2018-02-15 17:44 ` Jerry Hoemann
2018-02-15 19:02 ` Ingo Molnar
2018-02-15 19:48 ` Peter Zijlstra
2018-02-16 18:44 ` [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware Tim Chen
2018-02-16 19:16 ` David Woodhouse
2018-02-16 23:46 ` Tim Chen
2018-02-17 10:26 ` Ingo Molnar
2018-02-19 9:20 ` Peter Zijlstra
2018-02-19 9:29 ` David Woodhouse
2018-02-19 9:39 ` Ingo Molnar
2018-02-19 9:44 ` David Woodhouse
2018-02-19 10:08 ` Peter Zijlstra
2018-02-19 9:36 ` Ingo Molnar
2018-02-12 8:27 ` [PATCH v2 0/6] Spectre v2 updates Paolo Bonzini
2018-02-13 7:59 ` Ingo Molnar
2018-02-19 10:50 [PATCH v3 1/4] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-20 10:29 ` [tip:x86/pti] " tip-bot for David Woodhouse
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