Re: [PATCH 05/15] KVM: x86: SVM: Adopt VMX style MSR intercepts in SVM

[Sean Christopherson <seanjc@google.com>]

On Wed, Nov 27, 2024, Aaron Lewis wrote:
> VMX MSR interception is done via three functions:
> 
>         vmx_disable_intercept_for_msr(vcpu, msr, type)
>         vmx_enable_intercept_for_msr(vcpu, msr, type)
>         vmx_set_intercept_for_msr(vcpu, msr, type, value)
> 
> While SVM uses
> 
>         set_msr_interception(vcpu, msrpm, msr, read, write)
> 
> The SVM code is not very intuitive (using 0 for enable and 1 for
> disable), and forces both read and write changes with each call which
> is not always required.
> 
> Add helpers functions to SVM to match VMX:
> 
>         svm_disable_intercept_for_msr(vcpu, msr, type)
>         svm_enable_intercept_for_msr(vcpu, msr, type)
>         svm_set_intercept_for_msr(vcpu, msr, type, enable_intercept)
> 
> Additionally, update calls to set_msr_interception() to use the new
> functions. This update is only made to calls that toggle interception
> for both read and write.
> 
> Keep the old paths for now, they will be deleted once all code is
> converted to the new helpers.
> 
> Opportunistically, the function svm_get_msr_bitmap_entries() is added
> to abstract the MSR bitmap from the intercept functions.  This will be
> needed later in the series when this code is hoisted to common code.
> 
> No functional change.
> 
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Co-Developed-by: Anish Ghulati <aghulati@google.com>

Needs Anish's SoB.

> Signed-off-by: Aaron Lewis <aaronlewis@google.com>