From: Andy Lutomirski <luto@amacapital.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Jarkko Nikula <jarkko.nikula@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH] x86/entry/64: Fix native_load_gs_index() SWAPGS handling with IRQ state tracing enabled
Date: Wed, 29 Nov 2017 06:33:37 -0800 [thread overview]
Message-ID: <D6A6B532-57B5-4393-A322-DD441BEE74C4@amacapital.net> (raw)
In-Reply-To: <20171129124711.slmq5emx4f26c4zp@hirez.programming.kicks-ass.net>
> On Nov 29, 2017, at 4:47 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
>> On Wed, Nov 29, 2017 at 08:09:51AM +0100, Ingo Molnar wrote:
>> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
>> index f81d50d7ceac..c0b52df8ee4f 100644
>> --- a/arch/x86/entry/entry_64.S
>> +++ b/arch/x86/entry/entry_64.S
>> @@ -945,16 +945,16 @@ idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0
>> */
>> ENTRY(native_load_gs_index)
>> FRAME_BEGIN
>> + SWAPGS /* switch from user GS to kernel GS */
>> pushfq
>> DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
>> TRACE_IRQS_OFF
>> - SWAPGS
>
> I'm thinking those moves it too far back; we should at least have
> interrupts disabled when we do SWAPGS, no? Also, curse paravirt.
>
I'll look in a few hours.
But we definitely can't have irqs on when running with user gs.
next prev parent reply other threads:[~2017-11-29 14:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-28 14:35 Suspend-to-ram/resume regression with commit ca37e57bbe0c Jarkko Nikula
2017-11-29 7:09 ` [PATCH] x86/entry/64: Fix native_load_gs_index() SWAPGS handling with IRQ state tracing enabled Ingo Molnar
2017-11-29 9:25 ` Jarkko Nikula
2017-11-29 9:28 ` Thomas Gleixner
2017-11-29 12:39 ` Jarkko Nikula
2017-11-29 12:47 ` Peter Zijlstra
2017-11-29 14:33 ` Andy Lutomirski [this message]
2017-11-29 14:56 ` David Laight
2017-11-29 16:22 ` Andy Lutomirski
2017-11-29 16:51 ` David Laight
2017-11-29 20:48 ` Linus Torvalds
2017-11-29 16:51 ` Andy Lutomirski
2017-11-29 17:57 ` Andy Lutomirski
2017-11-29 18:08 ` Peter Zijlstra
2017-11-29 18:12 ` Andy Lutomirski
2017-11-29 20:58 ` Linus Torvalds
2017-11-29 21:25 ` Andy Lutomirski
2017-11-29 21:41 ` Andy Lutomirski
2017-11-29 21:57 ` Andy Lutomirski
2017-11-30 8:42 ` Jarkko Nikula
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