RE: [PATCH v3 06/11] KVM: SVM: Add new intercept vector in vmcb_control_area

[Babu Moger <babu.moger@amd.com>]

> -----Original Message-----
> From: Jim Mattson <jmattson@google.com>
> Sent: Wednesday, July 29, 2020 4:24 PM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>; Vitaly Kuznetsov
> <vkuznets@redhat.com>; Wanpeng Li <wanpengli@tencent.com>; Sean
> Christopherson <sean.j.christopherson@intel.com>; kvm list
> <kvm@vger.kernel.org>; Joerg Roedel <joro@8bytes.org>; the arch/x86
> maintainers <x86@kernel.org>; LKML <linux-kernel@vger.kernel.org>; Ingo
> Molnar <mingo@redhat.com>; Borislav Petkov <bp@alien8.de>; H . Peter Anvin
> <hpa@zytor.com>; Thomas Gleixner <tglx@linutronix.de>
> Subject: Re: [PATCH v3 06/11] KVM: SVM: Add new intercept vector in
> vmcb_control_area
> 
> On Tue, Jul 28, 2020 at 4:38 PM Babu Moger <babu.moger@amd.com> wrote:
> >
> > The new intercept bits have been added in vmcb control area to support
> > few more interceptions. Here are the some of them.
> >  - INTERCEPT_INVLPGB,
> >  - INTERCEPT_INVLPGB_ILLEGAL,
> >  - INTERCEPT_INVPCID,
> >  - INTERCEPT_MCOMMIT,
> >  - INTERCEPT_TLBSYNC,
> >
> > Add new intercept vector in vmcb_control_area to support these instructions.
> > Also update kvm_nested_vmrun trace function to support the new addition.
> >
> > AMD documentation for these instructions is available at "AMD64
> > Architecture Programmer’s Manual Volume 2: System Programming, Pub.
> > 24593 Rev. 3.34(or later)"
> >
> > The documentation can be obtained at the links below:
> > Link:
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
> >
> amd.com%2Fsystem%2Ffiles%2FTechDocs%2F24593.pdf&amp;data=02%7C01%
> 7Cbab
> >
> u.moger%40amd.com%7C04dafd87052d4ed59f9808d83405b0a4%7C3dd8961fe
> 4884e6
> >
> 08e11a82d994e183d%7C0%7C0%7C637316547054108593&amp;sdata=2ncYK2
> NY1J3xL
> > 9ZXSdb24zq0M0ZkF0iy%2FIW7SUDoFeg%3D&amp;reserved=0
> > Link:
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugz
> >
> illa.kernel.org%2Fshow_bug.cgi%3Fid%3D206537&amp;data=02%7C01%7Cbab
> u.m
> >
> oger%40amd.com%7C04dafd87052d4ed59f9808d83405b0a4%7C3dd8961fe488
> 4e608e
> >
> 11a82d994e183d%7C0%7C0%7C637316547054108593&amp;sdata=Trw3tJE1Z6
> dOTXi0
> > DbPhOUAh4Ulr7HxxoJNpM2IjbvM%3D&amp;reserved=0
> >
> > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > ---
> 
> > @@ -16,6 +16,7 @@ enum vector_offset {
> >         EXCEPTION_VECTOR,
> >         INTERCEPT_VECTOR_3,
> >         INTERCEPT_VECTOR_4,
> > +       INTERCEPT_VECTOR_5,
> >         MAX_VECTORS,
> >  };
> 
> Is this enumeration actually adding any value?

Yea. It is not much of a value add. It helps readability a little bit.
That’s why I kept that way. Thanks

> vmcb->control.intercepts[INTERCEPT_VECTOR_5] doesn't seem in any way
> "better" than just vmcb->control.intercepts[5].
> 
> Reviewed-by: Jim Mattson <jmattson@google.com>