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From: "H. Peter Anvin" <hpa@zytor.com>
To: Pavel Machek <pavel@ucw.cz>, linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org,
	"x86@kernel.org" <x86@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	stable@vger.kernel.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Juergen Gross <jgross@suse.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@redhat.com>,
	Chen Yu <yu.c.chen@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Borislav Petkov <bp@suse.de>,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [tip: x86/urgent] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h
Date: Sat, 24 Aug 2019 14:35:40 -0700	[thread overview]
Message-ID: <409703ae-6d70-3f6a-d6fc-b7dada3c2797@zytor.com> (raw)
In-Reply-To: <20190824181929.GA18551@amd>

On 8/24/19 11:19 AM, Pavel Machek wrote:
> On Fri 2019-08-23 01:10:49, tip-bot2 for Tom Lendacky wrote:
>> The following commit has been merged into the x86/urgent branch of tip:
>>
>> Commit-ID:     c49a0a80137c7ca7d6ced4c812c9e07a949f6f24
>> Gitweb:        https://git.kernel.org/tip/c49a0a80137c7ca7d6ced4c812c9e07a949f6f24
>> Author:        Tom Lendacky <thomas.lendacky@amd.com>
>> AuthorDate:    Mon, 19 Aug 2019 15:52:35 
>> Committer:     Borislav Petkov <bp@suse.de>
>> CommitterDate: Mon, 19 Aug 2019 19:42:52 +02:00
>>
>> x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h
>>
>> There have been reports of RDRAND issues after resuming from suspend on
>> some AMD family 15h and family 16h systems. This issue stems from a BIOS
>> not performing the proper steps during resume to ensure RDRAND continues
>> to function properly.
> 
> There are quite a few unanswered questions here.
> 
> a) Is there/should there be CVE for this?
> 
> b) Can we perform proper steps in kernel, thus making RDRAND usable
> even when BIOS is buggy?
> 

The kernel should at least be able to set its internal "CPUID" bit, visible
through /proc/cpuinfo.

	-hpa


  reply	other threads:[~2019-08-24 21:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-19 15:52 [PATCH v2] " Lendacky, Thomas
2019-08-23  1:10 ` [tip: x86/urgent] " tip-bot2 for Tom Lendacky
2019-08-24 13:50   ` Sasha Levin
2019-08-24 19:13     ` Borislav Petkov
2019-08-24 18:19   ` Pavel Machek
2019-08-24 21:35     ` H. Peter Anvin [this message]
2019-10-08 21:20       ` Pavel Machek

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