linux-kernel - Re: [PATCH v1 0/3] x86/traps: Fix DR6/DR7 inintialization

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Message-ID: <ac28b350-91a4-4e6d-bca6-4e0c80f4f503@intel.com>
Date: Fri, 13 Jun 2025 15:43:33 -0700
From: Sohil Mehta <sohil.mehta@...el.com>
To: "Xin Li (Intel)" <xin@...or.com>, <linux-kernel@...r.kernel.org>,
	<kvm@...r.kernel.org>
CC: <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>, <x86@...nel.org>, <hpa@...or.com>,
	<seanjc@...gle.com>, <pbonzini@...hat.com>, <peterz@...radead.org>,
	<brgerst@...il.com>, <tony.luck@...el.com>, <fenghuay@...dia.com>
Subject: Re: [PATCH v1 0/3] x86/traps: Fix DR6/DR7 inintialization

On 6/13/2025 12:01 AM, Xin Li (Intel) wrote:

> 
> Xin Li (Intel) (3):
>   x86/traps: Move DR7_RESET_VALUE to <uapi/asm/debugreg.h>
>   x86/traps: Initialize DR7 by writing its architectural reset value
>   x86/traps: Initialize DR6 by writing its architectural reset value
> 

The patches fix the false bus_lock warning that I was observing with the
infinite sigtrap selftest.

Tested-by: Sohil Mehta <sohil.mehta@...el.com>

I'll try it out again once you send the updated version.

In future, should we incorporate a #DB (or bus_lock) specific selftest
to detect such DR6/7 initialization issues?