linux-kernel - Re: [PATCH v5 17/19] KVM: VMX: Use VMX_FEATURE

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Date:   Mon, 13 Jan 2020 10:37:05 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Tony Luck <tony.luck@...el.com>,
        Tony W Wang-oc <TonyWWang-oc@...oxin.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Len Brown <lenb@...nel.org>, Shuah Khan <shuah@...nel.org>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-edac@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kselftest@...r.kernel.org, Borislav Petkov <bp@...e.de>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Subject: Re: [PATCH v5 17/19] KVM: VMX: Use VMX_FEATURE_* flags to define
 VMCS control bits

On Mon, Jan 13, 2020 at 07:32:28PM +0100, Borislav Petkov wrote:
> On Fri, Dec 20, 2019 at 08:45:11PM -0800, Sean Christopherson wrote:
> > Define the VMCS execution control flags (consumed by KVM) using their
> > associated VMX_FEATURE_* to provide a strong hint that new VMX features
> > are expected to be added to VMX_FEATURE and considered for reporting via
> > /proc/cpuinfo.
> > 
> > No functional change intended.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> > ---
> >  arch/x86/include/asm/vmx.h | 105 +++++++++++++++++++------------------
> >  1 file changed, 55 insertions(+), 50 deletions(-)
> > 
> > diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> > index 1835767aa335..9fbba31be825 100644
> > --- a/arch/x86/include/asm/vmx.h
> > +++ b/arch/x86/include/asm/vmx.h
> > @@ -15,67 +15,70 @@
> >  #include <linux/bitops.h>
> >  #include <linux/types.h>
> >  #include <uapi/asm/vmx.h>
> > +#include <asm/vmxfeatures.h>
> > +
> > +#define VMCS_CONTROL_BIT(x)	BIT(VMX_FEATURE_##x & 0x1f)
> >  
> >  /*
> >   * Definitions of Primary Processor-Based VM-Execution Controls.
> >   */
> > -#define CPU_BASED_VIRTUAL_INTR_PENDING          0x00000004
> > -#define CPU_BASED_USE_TSC_OFFSETING             0x00000008
> > -#define CPU_BASED_HLT_EXITING                   0x00000080
> > -#define CPU_BASED_INVLPG_EXITING                0x00000200
> > -#define CPU_BASED_MWAIT_EXITING                 0x00000400
> > -#define CPU_BASED_RDPMC_EXITING                 0x00000800
> > -#define CPU_BASED_RDTSC_EXITING                 0x00001000
> > -#define CPU_BASED_CR3_LOAD_EXITING		0x00008000
> > -#define CPU_BASED_CR3_STORE_EXITING		0x00010000
> > -#define CPU_BASED_CR8_LOAD_EXITING              0x00080000
> > -#define CPU_BASED_CR8_STORE_EXITING             0x00100000
> > -#define CPU_BASED_TPR_SHADOW                    0x00200000
> > -#define CPU_BASED_VIRTUAL_NMI_PENDING		0x00400000
> > -#define CPU_BASED_MOV_DR_EXITING                0x00800000
> > -#define CPU_BASED_UNCOND_IO_EXITING             0x01000000
> > -#define CPU_BASED_USE_IO_BITMAPS                0x02000000
> > -#define CPU_BASED_MONITOR_TRAP_FLAG             0x08000000
> > -#define CPU_BASED_USE_MSR_BITMAPS               0x10000000
> > -#define CPU_BASED_MONITOR_EXITING               0x20000000
> > -#define CPU_BASED_PAUSE_EXITING                 0x40000000
> > -#define CPU_BASED_ACTIVATE_SECONDARY_CONTROLS   0x80000000
> > +#define CPU_BASED_VIRTUAL_INTR_PENDING          VMCS_CONTROL_BIT(VIRTUAL_INTR_PENDING)
> > +#define CPU_BASED_USE_TSC_OFFSETING             VMCS_CONTROL_BIT(TSC_OFFSETTING)
> 
> checkpatch correctly complains here:
> 
> WARNING: 'OFFSETING' may be misspelled - perhaps 'OFFSETTING'?
> #80: FILE: arch/x86/include/asm/vmx.h:26:
> +#define CPU_BASED_USE_TSC_OFFSETING             VMCS_CONTROL_BIT(TSC_OFFSETTING)
> 
> and VMX_FEATURE_TSC_OFFSETTING is correct.
> 
> Should I fix it up to CPU_BASED_USE_TSC_OFFSETTING while applying?

No, the CPU_BASED_* defines are used by existing KVM code, i.e. you'd
also have to touch a bunch of KVM code.


$ git grep CPU_BASED_USE_TSC_OFFSETING
arch/x86/include/asm/vmx.h:#define CPU_BASED_USE_TSC_OFFSETING             0x00000008
arch/x86/kvm/vmx/nested.c:      if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
arch/x86/kvm/vmx/nested.c:      if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
arch/x86/kvm/vmx/nested.c:      if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
arch/x86/kvm/vmx/nested.c:              CPU_BASED_VIRTUAL_NMI_PENDING | CPU_BASED_USE_TSC_OFFSETING |
arch/x86/kvm/vmx/vmx.c:     (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING))
arch/x86/kvm/vmx/vmx.c:     (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING))
arch/x86/kvm/vmx/vmx.c:       CPU_BASED_USE_TSC_OFFSETING |
tools/testing/selftests/kvm/include/x86_64/vmx.h:#define CPU_BASED_USE_TSC_OFFSETING            0x00000008
tools/testing/selftests/kvm/x86_64/vmx_tsc_adjust_test.c:       control |= CPU_BASED_USE_MSR_BITMAPS | CPU_BASED_USE_TSC_OFFSETING;