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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Andy Lutomirski <luto@amacapital.net>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	xen-devel <xen-devel@lists.xen.org>,
	Borislav Petkov <bp@alien8.de>,
	David Vrabel <david.vrabel@citrix.com>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [Xen-devel] [PATCH] xen/x86: Adjust stack pointer in xen_sysexit
Date: Tue, 17 Nov 2015 14:38:28 -0500	[thread overview]
Message-ID: <564B8234.4000004@oracle.com> (raw)
In-Reply-To: <564B81DE.90909@oracle.com>

On 11/17/2015 02:37 PM, Boris Ostrovsky wrote:
> On 11/17/2015 02:16 PM, Andy Lutomirski wrote:
>>>> Looks good to me.  Does Xen have any sysexit/sysret32 equivalent to
>>>> return to 32-bit user mode?  If so, it could be worth trying to wire
>>>> it up by patching the jz instead of the test instruction.
>
> We can actually make patching a little bit more efficient by replacing 
> the test instruction with 'xor %eax,%eax'. That way we won't need any 
> 'nop's.

Nevermind that, we are looking at flags, not register.

-boris

  reply	other threads:[~2015-11-17 19:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-13 23:18 [PATCH] xen/x86: Adjust stack pointer in xen_sysexit Boris Ostrovsky
2015-11-13 23:26 ` Andy Lutomirski
2015-11-14  1:23   ` Boris Ostrovsky
2015-11-15 18:02     ` Andy Lutomirski
2015-11-16 16:25       ` Boris Ostrovsky
2015-11-16 19:03         ` Andy Lutomirski
2015-11-16 19:59           ` Borislav Petkov
2015-11-16 20:11             ` Andy Lutomirski
2015-11-16 20:22               ` Borislav Petkov
2015-11-16 20:48                 ` Boris Ostrovsky
2015-11-16 20:50                   ` Andy Lutomirski
2015-11-16 21:00                     ` Borislav Petkov
     [not found]                     ` <20151116210314.GA10307@char.us.oracle.com>
2015-11-16 21:04                       ` Andy Lutomirski
2015-11-17 10:53                         ` Joao Martins
2015-11-16 21:55                 ` H. Peter Anvin
2015-11-17 14:40                   ` Boris Ostrovsky
2015-11-17 18:49                     ` Andy Lutomirski
2015-11-17 19:12                       ` [Xen-devel] " Andrew Cooper
2015-11-17 19:16                         ` Andy Lutomirski
2015-11-17 19:21                           ` Borislav Petkov
2015-11-17 19:29                           ` Andrew Cooper
2015-11-17 19:36                             ` Andy Lutomirski
2015-11-17 19:37                           ` Boris Ostrovsky
2015-11-17 19:38                             ` Boris Ostrovsky [this message]
2015-11-16 20:31           ` Boris Ostrovsky

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