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From: Borislav Petkov <bp@suse.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Brian Gerst <brgerst@gmail.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 10/18] x86/asm/32: Pull MSR_IA32_SYSENTER_CS update code out of native_load_sp0()
Date: Fri, 27 Oct 2017 22:11:53 +0200	[thread overview]
Message-ID: <20171027201153.GF12039@nazgul.tnic> (raw)
In-Reply-To: <75b2372395f579c20ee6fd53d03eb79c6eea8e81.1509006199.git.luto@kernel.org>

On Thu, Oct 26, 2017 at 01:26:42AM -0700, Andy Lutomirski wrote:
> This causees the MSR_IA32_SYSENTER_CS write to move out of the

Spellcheck pls.

> paravirt hook.  This shouldn't affect Xen PV: Xen already ignores
> MSR_IA32_SYSENTER_ESP writes.  In any event, Xen doesn't support
> vm86() in a useful way.
> 
> Note to any potential backporters: This patch won't break lguest, as
> lguest didn't have any SYSENTER support at all.

...

> diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
> index 11966251cd42..84d6c9f554d0 100644
> --- a/arch/x86/kernel/process_32.c
> +++ b/arch/x86/kernel/process_32.c
> @@ -287,6 +287,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
>  	 * current_thread_info().
>  	 */
>  	load_sp0(tss, next);
> +	refresh_sysenter_cs(next);  /* in case prev or next is vm86 */

Ewww, side comments.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

  parent reply	other threads:[~2017-10-27 20:11 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-26  8:26 [PATCH 00/18] Pile o' entry/exit/sp0 changes Andy Lutomirski
2017-10-26  8:26 ` [PATCH 01/18] x86/asm/64: Remove the restore_c_regs_and_iret label Andy Lutomirski
2017-10-26 15:07   ` Borislav Petkov
2017-11-10  6:08   ` [01/18] " kemi
2017-10-26  8:26 ` [PATCH 02/18] x86/asm/64: Split the iret-to-user and iret-to-kernel paths Andy Lutomirski
2017-10-27 18:05   ` Dave Hansen
2017-11-01 11:34     ` Andy Lutomirski
2017-10-27 20:04   ` Borislav Petkov
2017-11-01 11:32     ` Andy Lutomirski
2017-10-26  8:26 ` [PATCH 03/18] x86/asm/64: Move SWAPGS into the common iret-to-usermode path Andy Lutomirski
2017-10-26 13:52   ` Brian Gerst
2017-10-26 14:13     ` Dave Hansen
2017-10-26 14:28       ` Borislav Petkov
2017-10-27 15:44         ` Andy Lutomirski
2017-10-27 18:08   ` Dave Hansen
2017-10-26  8:26 ` [PATCH 04/18] x86/asm/64: Simplify reg restore code in the standard IRET paths Andy Lutomirski
2017-10-26  8:26 ` [PATCH 05/18] x86/asm/64: Shrink paranoid_exit_restore and make labels local Andy Lutomirski
2017-10-27 20:07   ` Borislav Petkov
2017-10-26  8:26 ` [PATCH 06/18] x86/asm/64: Use pop instead of movq in syscall_return_via_sysret Andy Lutomirski
2017-10-27 20:11   ` Borislav Petkov
2017-10-26  8:26 ` [PATCH 07/18] x86/asm/64: Merge the fast and slow SYSRET paths Andy Lutomirski
2017-10-27 20:11   ` Borislav Petkov
2017-11-01 11:29     ` Andy Lutomirski
2017-11-01 12:35       ` Borislav Petkov
2017-11-01 17:26         ` Thomas Gleixner
2017-11-01 17:25   ` Brian Gerst
2017-11-01 20:35     ` Andy Lutomirski
2017-10-26  8:26 ` [PATCH 08/18] xen: add xen nmi trap entry Andy Lutomirski
2017-10-26  8:26 ` [PATCH 09/18] x86/asm/64: De-Xen-ify our NMI code Andy Lutomirski
2017-10-26  8:41   ` Juergen Gross
2017-10-27 20:11   ` Borislav Petkov
2017-10-26  8:26 ` [PATCH 10/18] x86/asm/32: Pull MSR_IA32_SYSENTER_CS update code out of native_load_sp0() Andy Lutomirski
2017-10-26 18:00   ` Brian Gerst
2017-10-27 13:51   ` Thomas Gleixner
2017-10-27 15:50     ` Andy Lutomirski
2017-10-27 20:11   ` Borislav Petkov [this message]
2017-10-26  8:26 ` [PATCH 11/18] x86/asm/64: Pass sp0 directly to load_sp0() Andy Lutomirski
2017-10-27 20:12   ` Borislav Petkov
2017-10-26  8:26 ` [PATCH 12/18] x86/asm: Add task_top_of_stack() to find the top of a task's stack Andy Lutomirski
2017-10-26  8:26 ` [PATCH 13/18] x86/xen/64: Clean up SP code in cpu_initialize_context() Andy Lutomirski
2017-10-26  8:43   ` Juergen Gross
2017-10-26  8:26 ` [PATCH 14/18] x86/boot/64: Stop initializing TSS.sp0 at boot Andy Lutomirski
2017-10-27 18:21   ` Dave Hansen
2017-10-28  8:10     ` Andy Lutomirski
2017-10-26  8:26 ` [PATCH 15/18] x86/asm/64: Remove all remaining direct thread_struct::sp0 reads Andy Lutomirski
2017-11-01 10:08   ` Borislav Petkov
2017-10-26  8:26 ` [PATCH 16/18] x86/boot/32: Fix cpu_current_top_of_stack initialization at boot Andy Lutomirski
2017-11-01 10:18   ` Borislav Petkov
2017-10-26  8:26 ` [PATCH 17/18] x86/asm/64: Remove thread_struct::sp0 Andy Lutomirski
2017-10-28  0:52   ` Brian Gerst
2017-11-01 10:23   ` Borislav Petkov
2017-11-01 10:40     ` Andy Lutomirski
2017-10-26  8:26 ` [PATCH 18/18] x86/traps: Use a new on_thread_stack() helper to clean up an assertion Andy Lutomirski
2017-11-01 10:31   ` Borislav Petkov
2017-11-01 10:45     ` Andy Lutomirski
2017-10-26 15:55 ` [PATCH 00/18] Pile o' entry/exit/sp0 changes Linus Torvalds
2017-10-28  7:31   ` Andy Lutomirski

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