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

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Message-ID: <Y+WaN8wW1EOvPbXe@google.com>
Date:   Fri, 10 Feb 2023 01:13:27 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>, 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

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()?