linux-kernel - RE: [PATCH Part2 v6 03/49] x86/sev: Add the host SEV-SNP initialization support

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Date:   Thu, 23 Jun 2022 22:22:52 +0000
From:   "Kalra, Ashish" <Ashish.Kalra@....com>
To:     Marc Orr <marcorr@...gle.com>
CC:     x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
        kvm list <kvm@...r.kernel.org>,
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        Linux Crypto Mailing List <linux-crypto@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
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        "jarkko@...nel.org" <jarkko@...nel.org>
Subject: RE: [PATCH Part2 v6 03/49] x86/sev: Add the host SEV-SNP
 initialization support

[AMD Official Use Only - General]

>> +static int __init snp_rmptable_init(void) {
>> +       if (!boot_cpu_has(X86_FEATURE_SEV_SNP))
>> +               return 0;
>> +
>> +       if (!iommu_sev_snp_supported())
>> +               goto nosnp;
>> +
>> +       if (__snp_rmptable_init())
>> +               goto nosnp;
>> +
>> +       cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, 
>> + "x86/rmptable_init:online", __snp_enable, NULL);
>> +
>> +       return 0;
>> +
>> +nosnp:
>> +       setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
>> +       return 1;

>Seems odd that we're returning 1 here, rather than 0. I tried to figure out how the initcall return values are used and failed. My impression was 0 means success and a negative number means failure.
>But maybe this is normal.

I think that initcall values are typically ignored, but it should return 0 on success and negative on error. So probably should fix this to return something like -ENOSYS instead of 1.

Thanks,
Ashish