From: Xin Li <xin@zytor.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
seanjc@google.com, pbonzini@redhat.com, brgerst@gmail.com,
tony.luck@intel.com, fenghuay@nvidia.com
Subject: Re: [PATCH v1 0/3] x86/traps: Fix DR6/DR7 inintialization
Date: Fri, 13 Jun 2025 00:37:46 -0700 [thread overview]
Message-ID: <457250dc-5e3f-498f-8b71-6ea4879f91af@zytor.com> (raw)
In-Reply-To: <20250613071842.GH2273038@noisy.programming.kicks-ass.net>
On 6/13/2025 12:18 AM, Peter Zijlstra wrote:
> On Fri, Jun 13, 2025 at 12:01:14AM -0700, Xin Li (Intel) wrote:
>>
>> Since only BLD-induced #DB exceptions clear DR6.BLD and other debug
>> exceptions leave it unchanged, even if the first #DB is unrelated to
>> BLD, DR6.BLD is still cleared. As a result, such a first #DB is
>> misinterpreted as a BLD #DB, and a false warning is triggerred.
>>
>>
>> Fix the bug by initializing DR6 by writing its architectural reset
>> value at boot time.
>>
>>
>> DR7 suffers from a similar issue. We apply the same fix.
>
> Bah, this DR6 polarity is a pain in the behind for sure. Patches look
> good, except I'm really not a fan of using those 'names'. But I'll not
> object too much of others like it.
Let's see if there will be more objections :)
next prev parent reply other threads:[~2025-06-13 7:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-13 7:01 Xin Li (Intel)
2025-06-13 7:01 ` [PATCH v1 1/3] x86/traps: Move DR7_RESET_VALUE to <uapi/asm/debugreg.h> Xin Li (Intel)
2025-06-13 14:18 ` Sean Christopherson
2025-06-13 17:58 ` Xin Li
2025-06-13 20:03 ` Sean Christopherson
2025-06-13 21:38 ` Xin Li
2025-06-13 7:01 ` [PATCH v1 2/3] x86/traps: Initialize DR7 by writing its architectural reset value Xin Li (Intel)
2025-06-13 7:15 ` Peter Zijlstra
2025-06-13 7:51 ` Xin Li
2025-06-13 7:59 ` H. Peter Anvin
2025-06-13 8:16 ` Peter Zijlstra
2025-06-13 14:10 ` Sean Christopherson
2025-06-13 17:36 ` Xin Li
2025-06-13 7:01 ` [PATCH v1 3/3] x86/traps: Initialize DR6 " Xin Li (Intel)
2025-06-13 7:18 ` [PATCH v1 0/3] x86/traps: Fix DR6/DR7 inintialization Peter Zijlstra
2025-06-13 7:37 ` Xin Li [this message]
2025-06-13 22:43 ` Sohil Mehta
2025-06-13 23:22 ` Xin Li
2025-06-14 3:38 ` H. Peter Anvin
2025-06-16 8:15 ` Ethan Zhao
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