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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
	Juergen Gross <jgross@suse.com>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [Xen-devel] [PATCH 2/4] xen/PVH: Use proper CS selector in long mode
Date: Wed, 2 May 2018 11:08:53 -0400	[thread overview]
Message-ID: <cb819dcb-1597-680e-31b3-b63fecb6d4c1@oracle.com> (raw)
In-Reply-To: <5AE9D27402000078001C02ED@prv1-mh.provo.novell.com>

On 05/02/2018 11:00 AM, Jan Beulich wrote:
>>>> On 02.05.18 at 16:57, <boris.ostrovsky@oracle.com> wrote:
>> On 05/02/2018 04:05 AM, Jan Beulich wrote:
>>>>>> On 30.04.18 at 18:23, <boris.ostrovsky@oracle.com> wrote:
>>>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>> Reviewed-by: Jan Beulich <jbeulich@suse.com>
>>>
>>> But to understand why things have been working nevertheless it would
>>> have been nice if the commit message wasn't empty, but instead said
>>> something like "The two happen to be identical on 64-bit."
>>
>> Why do you think they are identical? __KERNEL_CS points to entry#12
>> (which we don't specify in PVH GDT) while __BOOT_CS is the second entry
>> (which we do create).
> That's 32-bit's __KERNEL_CS. If the two weren't identical, the ljmp
> you adjust would never have worked afaict.


Oh, right. My theory was that we were picking up something from the
stack (which is where 12th entry would be pointing) and the L bit, which
I think is the only one we'd care about, happened to always be set there.

-boris

  parent reply	other threads:[~2018-05-02 15:06 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-30 16:23 [PATCH 0/4] PVH GDT fixes and cleanup Boris Ostrovsky
2018-04-30 16:23 ` [PATCH 1/4] xen/PVH: Replace GDT_ENTRY with explicit constant Boris Ostrovsky
2018-04-30 16:23   ` Boris Ostrovsky
2018-04-30 16:57   ` [Xen-devel] " Roger Pau Monné
2018-04-30 18:07     ` Boris Ostrovsky
2018-04-30 18:07     ` [Xen-devel] " Boris Ostrovsky
2018-05-01  7:53       ` Roger Pau Monné
2018-05-01  7:53       ` [Xen-devel] " Roger Pau Monné
2018-05-01  7:53         ` Roger Pau Monné
2018-05-01 12:16         ` Boris Ostrovsky
2018-05-01 12:16         ` [Xen-devel] " Boris Ostrovsky
2018-04-30 16:57   ` Roger Pau Monné
2018-05-01 11:31   ` David Laight
2018-05-01 11:31   ` David Laight
2018-05-01 12:40     ` Boris Ostrovsky
2018-05-01 12:40     ` Boris Ostrovsky
2018-05-02  8:00   ` [Xen-devel] " Jan Beulich
2018-05-02 14:53     ` Boris Ostrovsky
2018-05-02 14:53     ` [Xen-devel] " Boris Ostrovsky
2018-05-02  8:00   ` Jan Beulich
2018-04-30 16:23 ` [PATCH 2/4] xen/PVH: Use proper CS selector in long mode Boris Ostrovsky
2018-05-02  8:05   ` Jan Beulich
2018-05-02  8:05   ` [Xen-devel] " Jan Beulich
2018-05-02 14:57     ` Boris Ostrovsky
2018-05-02 15:00       ` Jan Beulich
2018-05-02 15:00       ` [Xen-devel] " Jan Beulich
2018-05-02 15:08         ` Boris Ostrovsky
2018-05-02 15:08         ` Boris Ostrovsky [this message]
2018-05-02 15:09           ` Jan Beulich
2018-05-02 15:09           ` [Xen-devel] " Jan Beulich
2018-05-02 15:28             ` Andrew Cooper
2018-05-02 15:28             ` [Xen-devel] " Andrew Cooper
2018-05-02 14:57     ` Boris Ostrovsky
2018-04-30 16:23 ` Boris Ostrovsky
2018-04-30 16:23 ` [PATCH 3/4] xen/PVH: Set up GS segment for stack canary Boris Ostrovsky
2018-05-02  8:16   ` Jan Beulich
2018-05-02  8:16   ` [Xen-devel] " Jan Beulich
2018-05-02 15:00     ` Boris Ostrovsky
2018-05-02 15:00     ` [Xen-devel] " Boris Ostrovsky
2018-05-02 15:01       ` Jan Beulich
2018-05-02 15:01       ` [Xen-devel] " Jan Beulich
2018-05-02 15:22         ` Boris Ostrovsky
2018-05-02 15:22         ` [Xen-devel] " Boris Ostrovsky
2018-05-02 15:41           ` Jan Beulich
2018-05-02 15:41           ` [Xen-devel] " Jan Beulich
2018-05-02 17:29             ` Boris Ostrovsky
2018-05-02 17:29             ` [Xen-devel] " Boris Ostrovsky
2018-05-03  7:35               ` Jan Beulich
2018-05-03  7:35               ` [Xen-devel] " Jan Beulich
2018-04-30 16:23 ` Boris Ostrovsky
2018-04-30 16:23 ` [PATCH 4/4] xen/PVH: Remove reserved entry in PVH GDT Boris Ostrovsky
2018-05-01  8:00   ` [Xen-devel] " Roger Pau Monné
2018-05-01 12:34     ` Boris Ostrovsky
2018-05-02  8:26       ` Jan Beulich
2018-05-02  8:26       ` [Xen-devel] " Jan Beulich
2018-05-02 15:06         ` Boris Ostrovsky
2018-05-02 15:06         ` [Xen-devel] " Boris Ostrovsky
2018-05-02 15:07           ` Jan Beulich
2018-05-02 15:07           ` [Xen-devel] " Jan Beulich
2018-05-01 12:34     ` Boris Ostrovsky
2018-05-01  8:00   ` Roger Pau Monné
2018-05-02  8:19   ` [Xen-devel] " Jan Beulich
2018-05-02  8:19   ` Jan Beulich
2018-04-30 16:23 ` Boris Ostrovsky

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