From: Zhenzhong Duan <zhenzhong.duan@oracle.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>, JBeulich@suse.com
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Xen-Devel <xen-devel@lists.xen.org>,
Srinivas REDDY Eeda <srinivas.eeda@oracle.com>
Subject: Re: [PATCH] Choose retpoline only when it is safe to use
Date: Tue, 6 Feb 2018 17:13:46 +0800 [thread overview]
Message-ID: <4f00a69a-4032-048d-3ffd-b7b6756ed596@oracle.com> (raw)
In-Reply-To: <00176009-d6ae-faa9-439c-0520c3c4788f@citrix.com>
在 2018/2/6 16:59, Andrew Cooper 写道:
> On 06/02/2018 08:43, Zhenzhong Duan wrote:
>> When ( ibrs && thunk == THUNK_DEFAULT && !retpoline_safe() ) is true,
>> thunk is set to THUNK_JMP rather than THUNK_RETPOLINE.
>>
>> When (!ibrs && thunk == THUNK_DEFAULT && !retpoline_safe() ) is true,
>> we should do the same.
>>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> Why? What improvement is this intended to give?
No improvement, I just feel if retpoline isn't safe, THUNK_JMP is better
and safer.
Above first check is working that way.
>
> (IOW, the logic here is deliberate, and has a specific purpose.)
Ok, Just ignore the noise if it's deliberate.
--
thanks
zduan
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next prev parent reply other threads:[~2018-02-06 9:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-06 8:43 [PATCH] Choose retpoline only when it is safe to use Zhenzhong Duan
2018-02-06 8:59 ` Andrew Cooper
2018-02-06 9:13 ` Zhenzhong Duan [this message]
2018-02-06 9:20 ` Andrew Cooper
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