From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4ECB12309B2 for ; Thu, 21 Nov 2024 03:55:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732161331; cv=none; b=PnBqwnZNUJynYjFdTCn5RHxM5veHEckznBIC5yaEGpSxsT46tyNno6FIYLmxn9g2y87Al+fIjXsIeYWxvtlsI29NYS77lcbEmIR4D+bi+2QyA9AG1nareeSmtjsZPVnJ6dMSeoMTpytyuhEYBLA4oTlFUZlJPp68bXJtwo42IP0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732161331; c=relaxed/simple; bh=8ZdPbwl61M7NNLaBpphYnWiwmQDRePEwBFPRVKjychA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Svh9t9/xuR4RO0fIFiKpg8U8wviLkJ/+GerbwHxDugSykdAUpybiwh/RFpkAz2PaDwejZn0E6rWxFZ07hrllFj0v8PUCekevQiI51CSkXWjP3s/p7+nHoXhBG3g71ou429DB9PGu99pss7xjdQwRk0YRqGR1lhx3W16Mx7YQHoQ= ARC-Authentication-Results:i=1; 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h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Xi57tlpiBFBOhbnzMJ0jU6+FuQq+DvGWlGmsxODBrLcR0YJXVfXq0KX1tza748eXI uKZTHMZCcgjxEgLUncdytEsm1c1VHFZmT6XPU1QoKn3cl1ztPyqg4ncwukr+PPQAgx vSqnMDViI9t96/Ux2Q7xi/dlT53Q4D34XVqdlmPdol42HRDUWj1koC+isMQ/jeUEPu IuUNvweu8ovU1DuJx1HeQ8GCJQ7abEM1abB2NCIfKKBShxdauSAFeuOEnl08qNaESW ke9lDUsuCJC0e4Z0iy7BmEAq80d3PBqeB/2ANOaBWE82gCrr6WYjq9f62Rd/kNgt9x TNmT2xa8C+/Hw== Message-ID: <3ff385ea-0b7a-441f-9905-4aad54c7575d@zytor.com> Date: Wed, 20 Nov 2024 19:54:54 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/1] x86/ia32: Normalize any null selector value to 0 To: Andrew Cooper Cc: bp@alien8.de, brgerst@gmail.com, dave.hansen@linux.intel.com, ebiederm@xmission.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org, Andy Lutomirski References: <20241120081721.2838905-1-xin@zytor.com> <3680972b-1871-4c92-9f61-c28ef7c10a4c@citrix.com> <7b819c31-1972-44e0-87c7-1d11ac13f530@citrix.com> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 11/20/2024 11:34 AM, Andrew Cooper wrote: > On 20/11/2024 7:09 pm, Xin Li wrote: >> On 11/20/2024 1:33 AM, Andrew Cooper wrote: >>> Right now, this change is codifying the problem behaviour we were trying >>> to fix out under FRED. >>> >>> Under FRED, if userspace loads e.g. 2 into a selector, it should remain >>> 2 until userspace changes it to something else. >> >> Okay, I will fix it by: >> 1) For null selector values, do nothing. >> 2) For non-null selector values, set RPL bits. >> >> sounds okay? > > Yeah, that sounds okay. Actually this is what v1 does: https://lore.kernel.org/lkml/20230706052231.2183-1-xin3.li@intel.com/ But obviously I need to rewrite the change log. > > The selftest ought to work under FRED, but it was speculative coding.  I > can't rule out that tweaks might be needed. The v1 makes the test happy with both IDT and FRED. Thanks! Xin