Re: [PATCH v1 1/3] x86/traps: Move DR7_RESET_VALUE to <uapi/asm/debugreg.h>

[Xin Li]

On 6/13/2025 1:03 PM, Sean Christopherson wrote:
> On Fri, Jun 13, 2025, Xin Li wrote:
> > On 6/13/2025 7:18 AM, Sean Christopherson wrote:
> > > On Fri, Jun 13, 2025, Xin Li (Intel) wrote:
> > > > Move DR7_RESET_VALUE to <uapi/asm/debugreg.h> to prepare to write DR7
> > > > with DR7_RESET_VALUE at boot time.
> > >
> > > Alternatively, what about dropping DR7_RESET_VALUE,  moving KVM's DR6 and DR7
> > > #defines out of arch/x86/include/asm/kvm_host.h, and then using DR7_FIXED_1?
> >
> > We definitely should do it, I see quite a few architectural definitions
> > are in KVM only headers (the native FRED patches needed to reuse the event
> > types that were previously VMX-specific and moved them out of KVM
> > headers).
> >
> > Because there is an UAPI header, we probably don't want to remove
> > definitions from it?
>
> What #defines are in which uapi header?

arch/x86/include/uapi/asm/debugreg.h has:

#define DR_BUS_LOCK     (0x800)         /* bus_lock */
#define DR_STEP         (0x4000)        /* single-step */
#define DR_SWITCH       (0x8000)        /* task switch */

And arch/x86/include/asm/kvm_host.h also has:

#define DR6_BUS_LOCK   (1 << 11)
#define DR6_BD          (1 << 13)
#define DR6_BS          (1 << 14)
#define DR6_BT          (1 << 15)
#define DR6_RTM         (1 << 16)

Duplicated definitions for the same DR6 bits.