KVM: x86: Remove KF() macro placeholder
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Message ID 20181105184432.18555-1-sean.j.christopherson@intel.com
State New
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Series
  • KVM: x86: Remove KF() macro placeholder
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Commit Message

Sean Christopherson Nov. 5, 2018, 6:44 p.m. UTC
Although well-intentioned, keeping the KF() definition as a hint for
handling scattered CPUID features may be counter-productive.  Simply
redefining the bit position only works for directly manipulating the
guest's CPUID leafs, e.g. it doesn't make guest_cpuid_has() magically
work.  Taking an alternative approach, e.g. ensuring the bit position
is identical between the Linux-defined and hardware-defined features,
may be a simpler and/or more effective method of exposing scattered
features to the guest.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/cpuid.c | 3 ---
 1 file changed, 3 deletions(-)

Comments

Paolo Bonzini Nov. 26, 2018, 4:48 p.m. UTC | #1
On 05/11/18 19:44, Sean Christopherson wrote:
> Although well-intentioned, keeping the KF() definition as a hint for
> handling scattered CPUID features may be counter-productive.  Simply
> redefining the bit position only works for directly manipulating the
> guest's CPUID leafs, e.g. it doesn't make guest_cpuid_has() magically
> work.  Taking an alternative approach, e.g. ensuring the bit position
> is identical between the Linux-defined and hardware-defined features,
> may be a simpler and/or more effective method of exposing scattered
> features to the guest.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kvm/cpuid.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 7bcfa61375c0..fb2feaf78daf 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -67,9 +67,6 @@ u64 kvm_supported_xcr0(void)
>  
>  #define F(x) bit(X86_FEATURE_##x)
>  
> -/* For scattered features from cpufeatures.h; we currently expose none */
> -#define KF(x) bit(KVM_CPUID_BIT_##x)
> -
>  int kvm_update_cpuid(struct kvm_vcpu *vcpu)
>  {
>  	struct kvm_cpuid_entry2 *best;
> 

Queued, thanks.

Paolo
Sean Christopherson Dec. 18, 2018, 8:51 p.m. UTC | #2
On Mon, Nov 26, 2018 at 05:48:55PM +0100, Paolo Bonzini wrote:
> On 05/11/18 19:44, Sean Christopherson wrote:
> > Although well-intentioned, keeping the KF() definition as a hint for
> > handling scattered CPUID features may be counter-productive.  Simply
> > redefining the bit position only works for directly manipulating the
> > guest's CPUID leafs, e.g. it doesn't make guest_cpuid_has() magically
> > work.  Taking an alternative approach, e.g. ensuring the bit position
> > is identical between the Linux-defined and hardware-defined features,
> > may be a simpler and/or more effective method of exposing scattered
> > features to the guest.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > ---
> >  arch/x86/kvm/cpuid.c | 3 ---
> >  1 file changed, 3 deletions(-)
> > 
> > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> > index 7bcfa61375c0..fb2feaf78daf 100644
> > --- a/arch/x86/kvm/cpuid.c
> > +++ b/arch/x86/kvm/cpuid.c
> > @@ -67,9 +67,6 @@ u64 kvm_supported_xcr0(void)
> >  
> >  #define F(x) bit(X86_FEATURE_##x)
> >  
> > -/* For scattered features from cpufeatures.h; we currently expose none */
> > -#define KF(x) bit(KVM_CPUID_BIT_##x)
> > -
> >  int kvm_update_cpuid(struct kvm_vcpu *vcpu)
> >  {
> >  	struct kvm_cpuid_entry2 *best;
> > 
> 
> Queued, thanks.
> 
> Paolo

Looks like this never made it to kvm/queue.
Radim Krčmář Dec. 20, 2018, 8:21 p.m. UTC | #3
2018-12-18 12:51-0800, Sean Christopherson:
> On Mon, Nov 26, 2018 at 05:48:55PM +0100, Paolo Bonzini wrote:
> > Queued, thanks.
> > 
> > Paolo
> 
> Looks like this never made it to kvm/queue.

The paths of the just are long.
Should be there now, thanks.

Patch
diff mbox series

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7bcfa61375c0..fb2feaf78daf 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -67,9 +67,6 @@  u64 kvm_supported_xcr0(void)
 
 #define F(x) bit(X86_FEATURE_##x)
 
-/* For scattered features from cpufeatures.h; we currently expose none */
-#define KF(x) bit(KVM_CPUID_BIT_##x)
-
 int kvm_update_cpuid(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpuid_entry2 *best;