From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 00A1E2F22 for ; Thu, 26 Jun 2025 13:32:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750944727; cv=none; b=u4UV1MabPr0ub2k72L7qjNi2jGyNHNGQCn/iwSVBlKmwYGDiBPrtQzpzbV5r44VDvseFC3PGV0H8dtOo3gZd/4C2txR2oh4pTnOpCW9fn+aebUEhD4/o7Rtwetm63pfz6LZUsfYY+L9UPdB4iNEURMSBlHk5MLpb1rU/cawNNvU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750944727; c=relaxed/simple; bh=AfPxERY5O1ODqtvE3jrBiWR4Wa3xTlBYcpIwRa/i1C4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=T5nnRdAQSWJGXO4vsnKMDy5Bct60hzWxKrp5lCpnu/S9my7DtPIC1E7BKb2VvvDge5DxgffhnGBawAKfEHh2boYaWnJ8cfqWQ1Rg0odFUosQjMho7IA8Pq/GTze3exYfVCLyc6DDNMQ4MJg0o/1+gyW06q2i0g5b0r2VRry1Pk4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Jxj//Zy2; arc=none smtp.client-ip=209.85.210.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Jxj//Zy2" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-7377139d8b1so881310b3a.0 for ; Thu, 26 Jun 2025 06:32:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1750944724; x=1751549524; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=ASrLckt86/ZNTRacVaov3vQ/UvbDNoBDf4mXFSO7YmE=; b=Jxj//Zy2L8P8zaFQyuha0cB3KsUq7TjdRSCHbEY0gLkT+DHS14bH/JGhkoLAZZB/up 2ftKZGxjJ5+MOT9HKlIzGc8ePcUa50dSRGswvTKeyJvrW37iaIwfdkBRTeYKFARHYtKV +j8yobDr6cgmht2V18XXUgXL2Jy40bjg/CDcTzwb3uVi9EHBLs5CAizsYBLMRJh7/t8g BLH8AzKIWzOo0uw1VTbzlG6LCdZmH5nEbwk1ZqJm18gc0XTVPDZb62Nmu4THNPrUjpEC gxWzLK7PDacoZTlo/NTabay/I8oE1uoBmngXJC74lfPK4YpThvp4pExPoIFL/BIyOO4F BK8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750944724; x=1751549524; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ASrLckt86/ZNTRacVaov3vQ/UvbDNoBDf4mXFSO7YmE=; b=IWUFNDZwSiJtdfOZCZGUtnt8ZbnJHZB9E9eGSRLsvGWhUzmNFY4Dtmjk6hJu2aRc1f t6v9NjgP3Y5qLx0OZE3zDSSymTK/BX8pDUbDF/rC3HdE5+PQkY6jr44xJx4k7+hXZCxU Ne3AVzKvoGGEK+T34vn6hJ2ha5GjJU9D9ikaUxlCO4G4sLqZ2vFXJqJdcmwjM1sH9oJh CuQQ09fCrk4YhcAOaRQLsizaKlJNveyElnyFPHZeeOuKtNO2AUG+/ty2FdVwV7V5sUuY Ek2clVyGRIuVTC3witjZv/tEU5EbgTueO9PUTLz4McCjlU93kDvrTq+Tv7qTWpdjAGLX 2nAQ== X-Forwarded-Encrypted: i=1; AJvYcCWLpi3gu/bVyr6hbYXNhAc5cVEMRKODCts//ume7HaowN0CX5rli6oDsCPiALT2jXa9rLQHrER1aGqWTDg=@vger.kernel.org X-Gm-Message-State: AOJu0Yz8qwRhR95ZrVilXjOGRBCWpN8mn7HukFw2oR22+q4X1UOg8Cue kXTpDsR8IndOhBVFfp2MIhdezgiOsOvS7tXc+lGI2ZvghFllFvOoQkjOM2h7G1HC+6LWjk69z9G wPIFc3g== X-Google-Smtp-Source: AGHT+IF9h4ysHLrlN9OOLpZXfLNb/gEg++gGgYd5FNTn15a550cl+YtJM7IYux7wvWO6MykGLBZMOCCwD08= X-Received: from pfvf9.prod.google.com ([2002:a05:6a00:1ac9:b0:746:2e5d:3e6a]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:c887:b0:218:9b3e:e8bd with SMTP id adf61e73a8af0-2207f206609mr9914651637.10.1750944724309; Thu, 26 Jun 2025 06:32:04 -0700 (PDT) Date: Thu, 26 Jun 2025 06:32:01 -0700 In-Reply-To: <20250626090439.GBaF0NJ34n065_4vb-@fat_crate.local> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <175079732220.406.9335430223954818839.tip-bot2@tip-bot2> <20250626090439.GBaF0NJ34n065_4vb-@fat_crate.local> Message-ID: Subject: Re: [tip: x86/urgent] x86/traps: Initialize DR7 by writing its architectural reset value From: Sean Christopherson To: Borislav Petkov Cc: "Xin Li (Intel)" , linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, Dave Hansen , "H. Peter Anvin (Intel)" , Sohil Mehta , "Peter Zijlstra (Intel)" , stable@vger.kernel.org, x86@kernel.org Content-Type: text/plain; charset="us-ascii" On Thu, Jun 26, 2025, Borislav Petkov wrote: > On Tue, Jun 24, 2025 at 08:35:22PM -0000, tip-bot2 for Xin Li (Intel) wrote: > > The following commit has been merged into the x86/urgent branch of tip: > > > > Commit-ID: fa7d0f83c5c4223a01598876352473cb3d3bd4d7 > > Gitweb: https://git.kernel.org/tip/fa7d0f83c5c4223a01598876352473cb3d3bd4d7 > > Author: Xin Li (Intel) > > AuthorDate: Fri, 20 Jun 2025 16:15:04 -07:00 > > Committer: Dave Hansen > > CommitterDate: Tue, 24 Jun 2025 13:15:52 -07:00 > > > > x86/traps: Initialize DR7 by writing its architectural reset value > > > > Initialize DR7 by writing its architectural reset value to always set > > bit 10, which is reserved to '1', when "clearing" DR7 so as not to > > trigger unanticipated behavior if said bit is ever unreserved, e.g. as > > a feature enabling flag with inverted polarity. > > OMG, who wrote that "text"? I'm pretty sure I can take credit for the latter half. You're welcome :-)