From: Andrii Anisov <andrii.anisov@gmail.com>
To: Julien Grall <julien.grall@arm.com>
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
"LOPEZ, FUENTES NACARINO Jairo Eduardo" <jairo@ruri.waseda.jp>,
xen-devel@lists.xen.org
Subject: Re: RT Xen on ARM - R-Car series
Date: Tue, 5 Feb 2019 11:01:51 +0200 [thread overview]
Message-ID: <ca035ab4-42c4-f397-c021-e9247761bef3@gmail.com> (raw)
In-Reply-To: <4f5c623d-ac64-a188-f20b-fa60166183e8@arm.com>
On 05.02.19 00:06, Julien Grall wrote:
>> A57+A53.
>>
>> I see the following in my log:
>>
>> (XEN) alternatives: Patching with alt table 00000000002c6608 -> 00000000002c6c80
>> (XEN) CPU0 will call ARM_SMCCC_ARCH_WORKAROUND_1 on exception entry
>> (XEN) CPU2 will call ARM_SMCCC_ARCH_WORKAROUND_1 on exception entry
>> (XEN) CPU3 will call ARM_SMCCC_ARCH_WORKAROUND_1 on exception entry
>> (XEN) CPU1 will call ARM_SMCCC_ARCH_WORKAROUND_1 on exception entry
>
> Cortex-A53 should not be affected by spectre v2, so I imagine they are only for A57?
Yes, the log says the workaround is applied to the big cores only. As it should be.
> It is going to be hard to disable the workarounds by default. But we can consider to provide host-wide or per-guest option to disable them on trusted environment.
We have to get numbers first than decide how to proceed.
>>> Also, when you mean possible, does it mean you haven't looked the performance regression?
>> We have a preliminary results about performance drop with xen4.12-unstable comparing to a our system with 4.10.
>
> A lot of patches have not been backported in Xen 4.10 (including Spectre/Meltdown) that will definitely fix hole but may have an impact on the performance. There were not backported because of performance reason but because of the complexity of the port and seemly lack of interest.
I know that story. But customers are customers. And performance drop in the next SW version is always painful for them.
So we need a good explanation (which Spectre mitigation might be), or better to show up no performance drop :).
--
Sincerely,
Andrii Anisov.
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next prev parent reply other threads:[~2019-02-05 9:01 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CACrvCsaeHuwzZzUQTzNYF7fqmgQWNJUVOQZv9D0MnYrXjqzZtQ@mail.gmail.com>
2018-12-22 12:21 ` RT Xen on ARM - R-Car series Andrii Anisov
2018-12-25 16:07 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2018-12-27 11:07 ` Andrii Anisov
2018-12-28 15:22 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2018-12-28 8:28 ` Andrii Anisov
2018-12-28 8:32 ` Andrii Anisov
2018-12-28 8:39 ` Andrii Anisov
2019-01-04 9:09 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-08 17:04 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-11 20:12 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-14 8:42 ` Andrii Anisov
2019-01-16 7:53 ` Andrii Anisov
2019-01-21 18:04 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
[not found] ` <CACrvCsZB-tps6=Vr=1Phf5oo5eUReabMLJzkbO3d2hmNLDOxww@mail.gmail.com>
[not found] ` <7e217489-2c1a-c35f-d51f-0969654aa8cc@gmail.com>
[not found] ` <CACrvCsaYJ-zGkZwfdV7BXDABW8u_EDQetU3pq+2otRGXWTXagw@mail.gmail.com>
[not found] ` <4d078801-b804-06e7-ad5c-8032b1dbaa84@gmail.com>
2019-01-28 17:20 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-28 8:25 ` Andrii Anisov
2019-01-29 15:30 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-29 13:29 ` Andrii Anisov
2019-01-30 20:23 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-30 12:12 ` Julien Grall
2019-01-31 11:22 ` Andrii Anisov
2019-01-31 11:37 ` Julien Grall
2019-01-31 12:00 ` Andrii Anisov
2019-01-31 12:20 ` Julien Grall
2019-01-31 21:56 ` Stefano Stabellini
2019-01-31 23:14 ` Julien Grall
2019-02-01 10:02 ` Andrii Anisov
2019-02-01 10:12 ` Julien Grall
2019-02-01 10:35 ` Andrii Anisov
2019-02-01 11:06 ` Julien Grall
2019-02-01 16:53 ` Roger Pau Monné
2019-02-01 17:40 ` Julien Grall
2019-02-04 10:28 ` Andrii Anisov
2019-02-04 11:21 ` Julien Grall
2019-02-04 14:46 ` Andrii Anisov
2019-02-04 15:05 ` Julien Grall
2019-02-04 12:53 ` Roger Pau Monné
2019-02-04 21:58 ` Julien Grall
2019-02-05 8:40 ` Andrii Anisov
2019-02-05 9:45 ` Roger Pau Monné
2019-02-05 9:54 ` Andrii Anisov
2019-02-05 10:10 ` Roger Pau Monné
2019-02-06 20:20 ` Andrii Anisov
2019-02-06 21:03 ` Stefano Stabellini
2019-02-07 9:42 ` Andrii Anisov
2019-02-07 10:35 ` Roger Pau Monné
2019-02-07 10:59 ` Julien Grall
2019-02-12 18:21 ` Andrii Anisov
2019-02-12 19:21 ` Julien Grall
2019-02-14 14:18 ` Andrii Anisov
2019-02-14 17:29 ` Julien Grall
2019-02-15 11:30 ` Andrii Anisov
2019-02-15 17:13 ` Julien Grall
2019-02-15 17:41 ` Andrii Anisov
2019-02-16 8:42 ` Julien Grall
2019-02-12 18:21 ` Andrii Anisov
2019-02-14 16:29 ` Roger Pau Monné
2019-02-15 15:21 ` Andrii Anisov
2019-02-15 16:31 ` Julien Grall
2019-02-15 17:30 ` Andrii Anisov
2019-02-15 18:36 ` Julien Grall
2019-02-14 17:08 ` Julien Grall
2019-02-05 9:26 ` Roger Pau Monné
2019-02-01 10:07 ` Andrii Anisov
2019-02-01 10:16 ` Julien Grall
2019-02-01 10:35 ` Andrii Anisov
2019-02-01 10:51 ` Julien Grall
2019-02-01 18:00 ` Stefano Stabellini
2019-02-04 10:32 ` Andrii Anisov
2019-02-04 11:36 ` Julien Grall
2019-02-04 15:19 ` Andrii Anisov
2019-02-04 22:06 ` Julien Grall
2019-02-05 9:01 ` Andrii Anisov [this message]
2019-02-05 19:18 ` Stefano Stabellini
2019-02-07 10:53 ` Andrii Anisov
[not found] ` <CACrvCsbkFG=3To83qi7xxmtmgC_9PKvuLz73edhiaV7TsJAZqQ@mail.gmail.com>
2019-01-31 12:24 ` Julien Grall
2019-01-16 20:46 ` Andrii Anisov
2019-01-16 7:40 ` Andrii Anisov
2019-01-17 2:08 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2018-12-28 17:35 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
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