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. https://lkml.org/lkml/2020/12/11/308 Signed-off-by: LeoLiu-oc <LeoLiu-oc@zhaoxin.com> ---  arch/x86/crypto/crc32c-intel_glue.c | 8 ++++++++  1 file changed, 8 insertions(+) diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c index feccb5254c7e..2d7fe5d24f5f 100644 --- a/arch/x86/crypto/crc32c-intel_glue.c +++ b/arch/x86/crypto/crc32c-intel_glue.c @@ -222,8 +222,16 @@ MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);  static int __init crc32c_intel_mod_init(void)  { +    struct cpuinfo_x86 *c = &boot_cpu_data; +      if (!x86_match_cpu(crc32c_cpu_id))          return -ENODEV; + +    if ((c->x86_vendor == X86_VENDOR_ZHAOXIN || c->x86_vendor == X86_VENDOR_CENTAUR) && +        (c->x86 <= 7 && c->x86_model <= 59)) { +            return -ENODEV; +    } +  #ifdef CONFIG_X86_64      if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {          alg.update = crc32c_pcl_intel_update; -- 2.20.1