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

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Message-ID: <a9628441-a242-4ef6-8d52-c3c3aba781b9@linux.intel.com>
Date: Mon, 16 Jun 2025 16:15:23 +0800
From: Ethan Zhao <haifeng.zhao@...ux.intel.com>
To: "H. Peter Anvin" <hpa@...or.com>, Xin Li <xin@...or.com>,
 Sohil Mehta <sohil.mehta@...el.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, 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

在 2025/6/14 11:38, H. Peter Anvin 写道:
> On June 13, 2025 4:22:57 PM PDT, Xin Li <xin@...or.com> wrote:
>> On 6/13/2025 3:43 PM, Sohil Mehta wrote:
>>> 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.
>> Thank you very much!
>>
>>> In future, should we incorporate a #DB (or bus_lock) specific selftest
>>> to detect such DR6/7 initialization issues?
>>
>> I cant think of how to tests it.  Any suggestion about a new test?
>>
> You would have to map some memory uncached.

To trigger a real bus_lock event in user space ?

Thanks,

Ethan

>
-- 
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