Re: [PATCH v8 3/5] x86/kvm: Add "nopvspin" parameter to disable PV spinlocks

[Sean Christopherson]

On Wed, Oct 23, 2019 at 07:16:22PM +0800, Zhenzhong Duan wrote:
> There are cases where a guest tries to switch spinlocks to bare metal
> behavior (e.g. by setting "xen_nopvspin" on XEN platform and
> "hv_nopvspin" on HYPER_V).
> 
> That feature is missed on KVM, add a new parameter "nopvspin" to disable
> PV spinlocks for KVM guest.
> 
> The new 'nopvspin' parameter will also replace Xen and Hyper-V specific
> parameters in future patches.
> 
> Define variable nopvsin as global because it will be used in future
> patches as above.
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Cc: Jonathan Corbet <corbet@xxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Radim Krcmar <rkrcmar@xxxxxxxxxx>
> Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> Cc: Jim Mattson <jmattson@xxxxxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> ---

Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>