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Commit 0550766a authored by LeoLiu-oc's avatar LeoLiu-oc Committed by Cheng Jian
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crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs

zhaoxin inclusion
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=19
CVE: NA

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The driver crc32c-intel match CPUs supporting X86_FEATURE_XMM4_2.
On platforms with Zhaoxin CPUs supporting this X86 feature,
when crc32c-intel and crc32c-generic are both registered,
system will use crc32c-intel because its .cra_priority is greater
than crc32c-generic.

When doing lmbench3 Create and Delete file test on partitions with
ext4 enabling metadata checksum, found using crc32c-generic driver
could get about 20% performance gain than using the driver
crc32c-intel on some Zhaoxin CPUs.

This case expect to use crc32c-generic driver for these Zhaoxin CPUs
to get performance gain, so remove these Zhaoxin CPUs support from
crc32c-intel.

This patch was submitted to mainline kernel but not accepted by upstream
maintainer whose reason is "Then create a BUG flag for it,".

We think this is not a CPU bug for Zhaoxin CPUs. So should patch the
crc32c driver for Zhaoxin CPUs but not report a BUG.

References: https://lkml.org/lkml/2020/12/11/308


Signed-off-by: default avatarLeoLiu-oc <LeoLiu-oc@zhaoxin.com>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
Reviewed-by: default avatarLeoLiu-oc <LeoLiu-oc@zhaoxin.com>
Signed-off-by: default avatarCheng Jian <cj.chengjian@huawei.com>
parent 43fcdf11
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