[linux-6.6.y] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs

[leoliu-oc]

zhaoxin inclusion
category: feature
CVE: NA

---

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.

[deepin-ci-robot]

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[deepin-ci-robot]

Hi @leoliu-oc. Thanks for your PR.

I'm waiting for a deepin-community member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[opsiff]

/ok-to-test

[opsiff]

/lgtm

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在新增的条件判断中，使用了未定义的常量 X86_VENDOR_ZHAOXIN 和 X86_VENDOR_CENTAUR，需要确认这些常量是否已经在代码库中定义。
• 新增代码中没有对 c->x86 和 c->x86_model 的范围进行限制，可能会导致整数溢出问题。
• 新增代码中没有处理 c->x86_vendor 为 X86_VENDOR_UNKNOWN 的情况，可能会导致未定义行为。

是否建议立即修改:
是