linux-kernel - Re: [RFC Part2 PATCH v3 05/26] KVM: SVM: Reserve ASID range for SEV guest

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Date:   Tue, 12 Sep 2017 15:24:05 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     Borislav Petkov <bp@...e.de>
Cc:     brijesh.singh@....com, linux-kernel@...r.kernel.org,
        x86@...nel.org, kvm@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Joerg Roedel <joro@...tes.org>,
        "Michael S . Tsirkin" <mst@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        \"Radim Krčmář\" <rkrcmar@...hat.com>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [RFC Part2 PATCH v3 05/26] KVM: SVM: Reserve ASID range for SEV
 guest



On 09/12/2017 03:04 PM, Borislav Petkov wrote:
...

>> SEV-enabled guest is from 1 to a maximum value defined via CPUID
>> Fn8000_001f[ECX].
> 
> I'd rewrite that to:
> 
> "The range of allowed SEV guest ASIDs is [1 - CPUID_8000_001F[ECX][31:0]]".
> 

thanks, will do.

...

>>   
>> +/* Secure Encrypted Virtualization */
> 
> If anything, this comment should explain what that variable is.
> Basically the comment you have in sev_hardware_setup() now.
> 

Will add more comments.

...

> 
> max_sev_asid is static and it is already initialized to 0 and thus this
> function can be simplified to:
> 
> /*
>   * Get maximum number of encrypted guest supported: Fn8001_001F[ECX].
>   *   [31:0]: Number of supported guests.
>   */
> static __init void sev_hardware_setup(void)
> {
>          max_sev_asid = cpuid_ecx(0x8000001F);
> }
> 

Agreed, I will improve it.

thanks