linux-kernel - Re: [PATCH 2/2] KVM: VMX: Stub out enable_evmcs static key for CONFIG

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Message-ID: <875yc97sl4.fsf@redhat.com>
Date:   Fri, 10 Feb 2023 10:55:19 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Tom Rix <trix@...hat.com>, kvm@...r.kernel.org,
        llvm@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: Re: [PATCH 2/2] KVM: VMX: Stub out enable_evmcs static key for
 CONFIG_HYPERV=n

Sean Christopherson <seanjc@...gle.com> writes:

> On Thu, Feb 09, 2023, Paolo Bonzini wrote:
>> On 2/9/23 14:13, Vitaly Kuznetsov wrote:
>> > > +static __always_inline bool is_evmcs_enabled(void)
>> > > +{
>> > > +	return static_branch_unlikely(&enable_evmcs);
>> > > +}
>> > I have a suggestion. While 'is_evmcs_enabled' name is certainly not
>> > worse than 'enable_evmcs', it may still be confusing as it's not clear
>> > which eVMCS is meant: are we running a guest using eVMCS or using eVMCS
>> > ourselves? So what if we rename this to a very explicit 'is_kvm_on_hyperv()'
>> > and hide the implementation details (i.e. 'evmcs') inside?
>> 
>> I prefer keeping eVMCS in the name,
>
> +1, IIUC KVM can run on Hyper-V without eVMCS being enabled.
>
>> but I agree a better name could be something like kvm_uses_evmcs()?
>
> kvm_is_using_evmcs()?
>

Sounds good to me!

-- 
Vitaly