Re: [PATCH v2 1/3] KVM: X86: Rename DR6_INIT to DR6_ACTIVE_LOW

[Paolo Bonzini]

On 02/02/21 16:02, Xiaoyao Li wrote:
> On 2/2/2021 10:49 PM, Paolo Bonzini wrote:
> > On 02/02/21 10:04, Chenyi Qiang wrote:
> > >  #define DR6_FIXED_1    0xfffe0ff0
> > > -#define DR6_INIT    0xffff0ff0
> > > +/*
> > > + * DR6_ACTIVE_LOW is actual the result of DR6_FIXED_1 | 
> > > ACTIVE_LOW_BITS.
> > > + * We can regard all the current FIXED_1 bits as active_low bits even
> > > + * though in no case they will be turned into 0. But if they are 
> > > defined
> > > + * in the future, it will require no code change.
> > > + * At the same time, it can be served as the init/reset value for DR6.
> > > + */
> > > +#define DR6_ACTIVE_LOW    0xffff0ff0
> > >  #define DR6_VOLATILE    0x0001e00f
> >
> > Committed with some changes in the wording of the comment.
> >
> > Also, DR6_FIXED_1 is (DR6_ACTIVE_LOW & ~DR6_VOLATILE).
>
> Maybe we can add BUILD_BUG_ON() to make sure the correctness?

We can even

#define DR_FIXED_1  (DR6_ACTIVE_LOW & ~DR6_VOLATILE)

directly.  I have pushed this patch to kvm/queue, but the other two will 
have to wait for Fenghua's bare metal support.

Paolo