linux-kernel - Re: [PATCH v2 0/3] Fix and cleanup for 32-bit PV sysexit

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Date:	Fri, 20 Nov 2015 00:02:32 +0100
From:	Borislav Petkov <bp@...e.de>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	david.vrabel@...rix.com, konrad.wilk@...cle.com, luto@...nel.org,
	linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
	virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH v2 0/3] Fix and cleanup for 32-bit PV sysexit

On Thu, Nov 19, 2015 at 04:55:44PM -0500, Boris Ostrovsky wrote:
> The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the
> earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit
> (and sysret32 in compat mode) pv ops, as suggested by Andy.
> 
> As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not
> used anymore by anyone and so can be removed.
> 
> 
> v2:
>   * patch both TEST and JZ intructions with a single JMP
>   * Add magic prefix to X86_FEATURE_XENPV comment to avoid having it printed in
>     /proc/cpuinfo
>   * Clarify in commit messages why irq_enable_sysexit and usergs_sysret32 are
>     removed
> 
> 
> Boris Ostrovsky (3):
>   x86/xen: Avoid fast syscall path for Xen PV guests
>   x86: irq_enable_sysexit pv op is no longer needed
>   x86: usergs_sysret32 pv op is no longer needed
> 
>  arch/x86/entry/entry_32.S             | 13 +++++--------
>  arch/x86/entry/entry_64_compat.S      | 20 ++++++++------------
>  arch/x86/include/asm/cpufeature.h     |  1 +
>  arch/x86/include/asm/paravirt.h       | 12 ------------
>  arch/x86/include/asm/paravirt_types.h | 17 -----------------
>  arch/x86/kernel/asm-offsets.c         |  3 ---
>  arch/x86/kernel/asm-offsets_64.c      |  1 -
>  arch/x86/kernel/paravirt.c            | 12 ------------
>  arch/x86/kernel/paravirt_patch_32.c   |  2 --
>  arch/x86/kernel/paravirt_patch_64.c   |  3 ---
>  arch/x86/xen/enlighten.c              |  7 +++----
>  arch/x86/xen/xen-asm_32.S             | 14 --------------
>  arch/x86/xen/xen-asm_64.S             | 19 -------------------
>  arch/x86/xen/xen-ops.h                |  3 ---
>  14 files changed, 17 insertions(+), 110 deletions(-)

All three look good to me.

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

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